src/backend/commands/tablecmds.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * tablecmds.c
   4  *        Commands for creating and altering table structures and settings
   5  *
   6  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.178 2006/03/03 03:30:52 tgl Exp $
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15 #include "postgres.h"
  16
  17 #include "access/genam.h"
  18 #include "access/tuptoaster.h"
  19 #include "catalog/catalog.h"
  20 #include "catalog/dependency.h"
  21 #include "catalog/heap.h"
  22 #include "catalog/index.h"
  23 #include "catalog/indexing.h"
  24 #include "catalog/namespace.h"
  25 #include "catalog/pg_constraint.h"
  26 #include "catalog/pg_depend.h"
  27 #include "catalog/pg_inherits.h"
  28 #include "catalog/pg_namespace.h"
  29 #include "catalog/pg_opclass.h"
  30 #include "catalog/pg_trigger.h"
  31 #include "catalog/pg_type.h"
  32 #include "commands/cluster.h"
  33 #include "commands/defrem.h"
  34 #include "commands/tablecmds.h"
  35 #include "commands/tablespace.h"
  36 #include "commands/trigger.h"
  37 #include "commands/typecmds.h"
  38 #include "executor/executor.h"
  39 #include "lib/stringinfo.h"
  40 #include "miscadmin.h"
  41 #include "nodes/makefuncs.h"
  42 #include "optimizer/clauses.h"
  43 #include "optimizer/plancat.h"
  44 #include "optimizer/prep.h"
  45 #include "parser/analyze.h"
  46 #include "parser/gramparse.h"
  47 #include "parser/parser.h"
  48 #include "parser/parse_clause.h"
  49 #include "parser/parse_coerce.h"
  50 #include "parser/parse_expr.h"
  51 #include "parser/parse_oper.h"
  52 #include "parser/parse_relation.h"
  53 #include "parser/parse_type.h"
  54 #include "rewrite/rewriteHandler.h"
  55 #include "storage/smgr.h"
  56 #include "utils/acl.h"
  57 #include "utils/builtins.h"
  58 #include "utils/fmgroids.h"
  59 #include "utils/inval.h"
  60 #include "utils/lsyscache.h"
  61 #include "utils/memutils.h"
  62 #include "utils/relcache.h"
  63 #include "utils/syscache.h"
  64
  65
  66 /*
  67  * ON COMMIT action list
  68  */
  69 typedef struct OnCommitItem
  70 {
  71         Oid                     relid;                  /* relid of relation */
  72         OnCommitAction oncommit;        /* what to do at end of xact */
  73
  74         /*
  75          * If this entry was created during the current transaction,
  76          * creating_subid is the ID of the creating subxact; if created in a prior
  77          * transaction, creating_subid is zero.  If deleted during the current
  78          * transaction, deleting_subid is the ID of the deleting subxact; if no
  79          * deletion request is pending, deleting_subid is zero.
  80          */
  81         SubTransactionId creating_subid;
  82         SubTransactionId deleting_subid;
  83 } OnCommitItem;
  84
  85 static List *on_commits = NIL;
  86
  87
  88 /*
  89  * State information for ALTER TABLE
  90  *
  91  * The pending-work queue for an ALTER TABLE is a List of AlteredTableInfo
  92  * structs, one for each table modified by the operation (the named table
  93  * plus any child tables that are affected).  We save lists of subcommands
  94  * to apply to this table (possibly modified by parse transformation steps);
  95  * these lists will be executed in Phase 2.  If a Phase 3 step is needed,
  96  * necessary information is stored in the constraints and newvals lists.
  97  *
  98  * Phase 2 is divided into multiple passes; subcommands are executed in
  99  * a pass determined by subcommand type.
 100  */
 101
 102 #define AT_PASS_DROP                    0               /* DROP (all flavors) */
 103 #define AT_PASS_ALTER_TYPE              1               /* ALTER COLUMN TYPE */
 104 #define AT_PASS_OLD_INDEX               2               /* re-add existing indexes */
 105 #define AT_PASS_OLD_CONSTR              3               /* re-add existing constraints */
 106 #define AT_PASS_COL_ATTRS               4               /* set other column attributes */
 107 /* We could support a RENAME COLUMN pass here, but not currently used */
 108 #define AT_PASS_ADD_COL                 5               /* ADD COLUMN */
 109 #define AT_PASS_ADD_INDEX               6               /* ADD indexes */
 110 #define AT_PASS_ADD_CONSTR              7               /* ADD constraints, defaults */
 111 #define AT_PASS_MISC                    8               /* other stuff */
 112 #define AT_NUM_PASSES                   9
 113
 114 typedef struct AlteredTableInfo
 115 {
 116         /* Information saved before any work commences: */
 117         Oid                     relid;                  /* Relation to work on */
 118         char            relkind;                /* Its relkind */
 119         TupleDesc       oldDesc;                /* Pre-modification tuple descriptor */
 120         /* Information saved by Phase 1 for Phase 2: */
 121         List       *subcmds[AT_NUM_PASSES]; /* Lists of AlterTableCmd */
 122         /* Information saved by Phases 1/2 for Phase 3: */
 123         List       *constraints;        /* List of NewConstraint */
 124         List       *newvals;            /* List of NewColumnValue */
 125         Oid                     newTableSpace;  /* new tablespace; 0 means no change */
 126         /* Objects to rebuild after completing ALTER TYPE operations */
 127         List       *changedConstraintOids;      /* OIDs of constraints to rebuild */
 128         List       *changedConstraintDefs;      /* string definitions of same */
 129         List       *changedIndexOids;           /* OIDs of indexes to rebuild */
 130         List       *changedIndexDefs;           /* string definitions of same */
 131 } AlteredTableInfo;
 132
 133 /* Struct describing one new constraint to check in Phase 3 scan */
 134 typedef struct NewConstraint
 135 {
 136         char       *name;                       /* Constraint name, or NULL if none */
 137         ConstrType      contype;                /* CHECK, NOT_NULL, or FOREIGN */
 138         AttrNumber      attnum;                 /* only relevant for NOT_NULL */
 139         Oid                     refrelid;               /* PK rel, if FOREIGN */
 140         Node       *qual;                       /* Check expr or FkConstraint struct */
 141         List       *qualstate;          /* Execution state for CHECK */
 142 } NewConstraint;
 143
 144 /*
 145  * Struct describing one new column value that needs to be computed during
 146  * Phase 3 copy (this could be either a new column with a non-null default, or
 147  * a column that we're changing the type of).  Columns without such an entry
 148  * are just copied from the old table during ATRewriteTable.  Note that the
 149  * expr is an expression over *old* table values.
 150  */
 151 typedef struct NewColumnValue
 152 {
 153         AttrNumber      attnum;                 /* which column */
 154         Expr       *expr;                       /* expression to compute */
 155         ExprState  *exprstate;          /* execution state */
 156 } NewColumnValue;
 157
 158
 159 static List *MergeAttributes(List *schema, List *supers, bool istemp,
 160                                 List **supOids, List **supconstr, int *supOidCount);
 161 static bool change_varattnos_of_a_node(Node *node, const AttrNumber *newattno);
 162 static void StoreCatalogInheritance(Oid relationId, List *supers);
 163 static int      findAttrByName(const char *attributeName, List *schema);
 164 static void setRelhassubclassInRelation(Oid relationId, bool relhassubclass);
 165 static bool needs_toast_table(Relation rel);
 166 static void AlterIndexNamespaces(Relation classRel, Relation rel,
 167                                          Oid oldNspOid, Oid newNspOid);
 168 static void AlterSeqNamespaces(Relation classRel, Relation rel,
 169                                    Oid oldNspOid, Oid newNspOid,
 170                                    const char *newNspName);
 171 static int transformColumnNameList(Oid relId, List *colList,
 172                                                 int16 *attnums, Oid *atttypids);
 173 static int transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
 174                                                    List **attnamelist,
 175                                                    int16 *attnums, Oid *atttypids,
 176                                                    Oid *opclasses);
 177 static Oid transformFkeyCheckAttrs(Relation pkrel,
 178                                                 int numattrs, int16 *attnums,
 179                                                 Oid *opclasses);
 180 static void validateForeignKeyConstraint(FkConstraint *fkconstraint,
 181                                                          Relation rel, Relation pkrel);
 182 static void createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
 183                                                  Oid constrOid);
 184 static char *fkMatchTypeToString(char match_type);
 185 static void ATController(Relation rel, List *cmds, bool recurse);
 186 static void ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 187                   bool recurse, bool recursing);
 188 static void ATRewriteCatalogs(List **wqueue);
 189 static void ATExecCmd(AlteredTableInfo *tab, Relation rel, AlterTableCmd *cmd);
 190 static void ATRewriteTables(List **wqueue);
 191 static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap);
 192 static AlteredTableInfo *ATGetQueueEntry(List **wqueue, Relation rel);
 193 static void ATSimplePermissions(Relation rel, bool allowView);
 194 static void ATSimpleRecursion(List **wqueue, Relation rel,
 195                                   AlterTableCmd *cmd, bool recurse);
 196 static void ATOneLevelRecursion(List **wqueue, Relation rel,
 197                                         AlterTableCmd *cmd);
 198 static void find_composite_type_dependencies(Oid typeOid,
 199                                                                  const char *origTblName);
 200 static void ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
 201                                 AlterTableCmd *cmd);
 202 static void ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
 203                                 ColumnDef *colDef);
 204 static void add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid);
 205 static void add_column_support_dependency(Oid relid, int32 attnum,
 206                                                           RangeVar *support);
 207 static void ATExecDropNotNull(Relation rel, const char *colName);
 208 static void ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
 209                                  const char *colName);
 210 static void ATExecColumnDefault(Relation rel, const char *colName,
 211                                         Node *newDefault);
 212 static void ATPrepSetStatistics(Relation rel, const char *colName,
 213                                         Node *flagValue);
 214 static void ATExecSetStatistics(Relation rel, const char *colName,
 215                                         Node *newValue);
 216 static void ATExecSetStorage(Relation rel, const char *colName,
 217                                  Node *newValue);
 218 static void ATExecDropColumn(Relation rel, const char *colName,
 219                                  DropBehavior behavior,
 220                                  bool recurse, bool recursing);
 221 static void ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
 222                            IndexStmt *stmt, bool is_rebuild);
 223 static void ATExecAddConstraint(AlteredTableInfo *tab, Relation rel,
 224                                         Node *newConstraint);
 225 static void ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
 226                                                   FkConstraint *fkconstraint);
 227 static void ATPrepDropConstraint(List **wqueue, Relation rel,
 228                                          bool recurse, AlterTableCmd *cmd);
 229 static void ATExecDropConstraint(Relation rel, const char *constrName,
 230                                          DropBehavior behavior, bool quiet);
 231 static void ATPrepAlterColumnType(List **wqueue,
 232                                           AlteredTableInfo *tab, Relation rel,
 233                                           bool recurse, bool recursing,
 234                                           AlterTableCmd *cmd);
 235 static void ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
 236                                           const char *colName, TypeName *typename);
 237 static void ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab);
 238 static void ATPostAlterTypeParse(char *cmd, List **wqueue);
 239 static void change_owner_recurse_to_sequences(Oid relationOid,
 240                                                                   Oid newOwnerId);
 241 static void ATExecClusterOn(Relation rel, const char *indexName);
 242 static void ATExecDropCluster(Relation rel);
 243 static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel,
 244                                         char *tablespacename);
 245 static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace);
 246 static void ATExecEnableDisableTrigger(Relation rel, char *trigname,
 247                                                    bool enable, bool skip_system);
 248 static void copy_relation_data(Relation rel, SMgrRelation dst);
 249 static void update_ri_trigger_args(Oid relid,
 250                                            const char *oldname,
 251                                            const char *newname,
 252                                            bool fk_scan,
 253                                            bool update_relname);
 254
 255
 256 /* ----------------------------------------------------------------
 257  *              DefineRelation
 258  *                              Creates a new relation.
 259  *
 260  * If successful, returns the OID of the new relation.
 261  * ----------------------------------------------------------------
 262  */
 263 Oid
 264 DefineRelation(CreateStmt *stmt, char relkind)
 265 {
 266         char            relname[NAMEDATALEN];
 267         Oid                     namespaceId;
 268         List       *schema = stmt->tableElts;
 269         Oid                     relationId;
 270         Oid                     tablespaceId;
 271         Relation        rel;
 272         TupleDesc       descriptor;
 273         List       *inheritOids;
 274         List       *old_constraints;
 275         bool            localHasOids;
 276         int                     parentOidCount;
 277         List       *rawDefaults;
 278         ListCell   *listptr;
 279         int                     i;
 280         AttrNumber      attnum;
 281
 282         /*
 283          * Truncate relname to appropriate length (probably a waste of time, as
 284          * parser should have done this already).
 285          */
 286         StrNCpy(relname, stmt->relation->relname, NAMEDATALEN);
 287
 288         /*
 289          * Check consistency of arguments
 290          */
 291         if (stmt->oncommit != ONCOMMIT_NOOP && !stmt->relation->istemp)
 292                 ereport(ERROR,
 293                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 294                                  errmsg("ON COMMIT can only be used on temporary tables")));
 295
 296         /*
 297          * Look up the namespace in which we are supposed to create the relation.
 298          * Check we have permission to create there. Skip check if bootstrapping,
 299          * since permissions machinery may not be working yet.
 300          */
 301         namespaceId = RangeVarGetCreationNamespace(stmt->relation);
 302
 303         if (!IsBootstrapProcessingMode())
 304         {
 305                 AclResult       aclresult;
 306
 307                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 308                                                                                   ACL_CREATE);
 309                 if (aclresult != ACLCHECK_OK)
 310                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 311                                                    get_namespace_name(namespaceId));
 312         }
 313
 314         /*
 315          * Select tablespace to use.  If not specified, use default_tablespace
 316          * (which may in turn default to database's default).
 317          */
 318         if (stmt->tablespacename)
 319         {
 320                 tablespaceId = get_tablespace_oid(stmt->tablespacename);
 321                 if (!OidIsValid(tablespaceId))
 322                         ereport(ERROR,
 323                                         (errcode(ERRCODE_UNDEFINED_OBJECT),
 324                                          errmsg("tablespace \"%s\" does not exist",
 325                                                         stmt->tablespacename)));
 326         }
 327         else
 328         {
 329                 tablespaceId = GetDefaultTablespace();
 330                 /* note InvalidOid is OK in this case */
 331         }
 332
 333         /* Check permissions except when using database's default */
 334         if (OidIsValid(tablespaceId))
 335         {
 336                 AclResult       aclresult;
 337
 338                 aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(),
 339                                                                                    ACL_CREATE);
 340                 if (aclresult != ACLCHECK_OK)
 341                         aclcheck_error(aclresult, ACL_KIND_TABLESPACE,
 342                                                    get_tablespace_name(tablespaceId));
 343         }
 344
 345         /*
 346          * Look up inheritance ancestors and generate relation schema, including
 347          * inherited attributes.
 348          */
 349         schema = MergeAttributes(schema, stmt->inhRelations,
 350                                                          stmt->relation->istemp,
 351                                                          &inheritOids, &old_constraints, &parentOidCount);
 352
 353         /*
 354          * Create a relation descriptor from the relation schema and create the
 355          * relation.  Note that in this stage only inherited (pre-cooked) defaults
 356          * and constraints will be included into the new relation.
 357          * (BuildDescForRelation takes care of the inherited defaults, but we have
 358          * to copy inherited constraints here.)
 359          */
 360         descriptor = BuildDescForRelation(schema);
 361
 362         localHasOids = interpretOidsOption(stmt->hasoids);
 363         descriptor->tdhasoid = (localHasOids || parentOidCount > 0);
 364
 365         if (old_constraints != NIL)
 366         {
 367                 ConstrCheck *check = (ConstrCheck *)
 368                 palloc0(list_length(old_constraints) * sizeof(ConstrCheck));
 369                 int                     ncheck = 0;
 370
 371                 foreach(listptr, old_constraints)
 372                 {
 373                         Constraint *cdef = (Constraint *) lfirst(listptr);
 374                         bool            dup = false;
 375
 376                         if (cdef->contype != CONSTR_CHECK)
 377                                 continue;
 378                         Assert(cdef->name != NULL);
 379                         Assert(cdef->raw_expr == NULL && cdef->cooked_expr != NULL);
 380
 381                         /*
 382                          * In multiple-inheritance situations, it's possible to inherit
 383                          * the same grandparent constraint through multiple parents.
 384                          * Hence, discard inherited constraints that match as to both name
 385                          * and expression.      Otherwise, gripe if the names conflict.
 386                          */
 387                         for (i = 0; i < ncheck; i++)
 388                         {
 389                                 if (strcmp(check[i].ccname, cdef->name) != 0)
 390                                         continue;
 391                                 if (strcmp(check[i].ccbin, cdef->cooked_expr) == 0)
 392                                 {
 393                                         dup = true;
 394                                         break;
 395                                 }
 396                                 ereport(ERROR,
 397                                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
 398                                                  errmsg("duplicate check constraint name \"%s\"",
 399                                                                 cdef->name)));
 400                         }
 401                         if (!dup)
 402                         {
 403                                 check[ncheck].ccname = cdef->name;
 404                                 check[ncheck].ccbin = pstrdup(cdef->cooked_expr);
 405                                 ncheck++;
 406                         }
 407                 }
 408                 if (ncheck > 0)
 409                 {
 410                         if (descriptor->constr == NULL)
 411                         {
 412                                 descriptor->constr = (TupleConstr *) palloc(sizeof(TupleConstr));
 413                                 descriptor->constr->defval = NULL;
 414                                 descriptor->constr->num_defval = 0;
 415                                 descriptor->constr->has_not_null = false;
 416                         }
 417                         descriptor->constr->num_check = ncheck;
 418                         descriptor->constr->check = check;
 419                 }
 420         }
 421
 422         relationId = heap_create_with_catalog(relname,
 423                                                                                   namespaceId,
 424                                                                                   tablespaceId,
 425                                                                                   InvalidOid,
 426                                                                                   GetUserId(),
 427                                                                                   descriptor,
 428                                                                                   relkind,
 429                                                                                   false,
 430                                                                                   localHasOids,
 431                                                                                   parentOidCount,
 432                                                                                   stmt->oncommit,
 433                                                                                   allowSystemTableMods);
 434
 435         StoreCatalogInheritance(relationId, inheritOids);
 436
 437         /*
 438          * We must bump the command counter to make the newly-created relation
 439          * tuple visible for opening.
 440          */
 441         CommandCounterIncrement();
 442
 443         /*
 444          * Open the new relation and acquire exclusive lock on it.      This isn't
 445          * really necessary for locking out other backends (since they can't see
 446          * the new rel anyway until we commit), but it keeps the lock manager from
 447          * complaining about deadlock risks.
 448          */
 449         rel = relation_open(relationId, AccessExclusiveLock);
 450
 451         /*
 452          * Now add any newly specified column default values and CHECK constraints
 453          * to the new relation.  These are passed to us in the form of raw
 454          * parsetrees; we need to transform them to executable expression trees
 455          * before they can be added. The most convenient way to do that is to
 456          * apply the parser's transformExpr routine, but transformExpr doesn't
 457          * work unless we have a pre-existing relation. So, the transformation has
 458          * to be postponed to this final step of CREATE TABLE.
 459          *
 460          * Another task that's conveniently done at this step is to add dependency
 461          * links between columns and supporting relations (such as SERIAL
 462          * sequences).
 463          *
 464          * First, scan schema to find new column defaults.
 465          */
 466         rawDefaults = NIL;
 467         attnum = 0;
 468
 469         foreach(listptr, schema)
 470         {
 471                 ColumnDef  *colDef = lfirst(listptr);
 472
 473                 attnum++;
 474
 475                 if (colDef->raw_default != NULL)
 476                 {
 477                         RawColumnDefault *rawEnt;
 478
 479                         Assert(colDef->cooked_default == NULL);
 480
 481                         rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
 482                         rawEnt->attnum = attnum;
 483                         rawEnt->raw_default = colDef->raw_default;
 484                         rawDefaults = lappend(rawDefaults, rawEnt);
 485                 }
 486
 487                 /* Create dependency for supporting relation for this column */
 488                 if (colDef->support != NULL)
 489                         add_column_support_dependency(relationId, attnum, colDef->support);
 490         }
 491
 492         /*
 493          * Parse and add the defaults/constraints, if any.
 494          */
 495         if (rawDefaults || stmt->constraints)
 496                 AddRelationRawConstraints(rel, rawDefaults, stmt->constraints);
 497
 498         /*
 499          * Clean up.  We keep lock on new relation (although it shouldn't be
 500          * visible to anyone else anyway, until commit).
 501          */
 502         relation_close(rel, NoLock);
 503
 504         return relationId;
 505 }
 506
 507 /*
 508  * RemoveRelation
 509  *              Deletes a relation.
 510  */
 511 void
 512 RemoveRelation(const RangeVar *relation, DropBehavior behavior)
 513 {
 514         Oid                     relOid;
 515         ObjectAddress object;
 516
 517         relOid = RangeVarGetRelid(relation, false);
 518
 519         object.classId = RelationRelationId;
 520         object.objectId = relOid;
 521         object.objectSubId = 0;
 522
 523         performDeletion(&object, behavior);
 524 }
 525
 526 /*
 527  * ExecuteTruncate
 528  *              Executes a TRUNCATE command.
 529  *
 530  * This is a multi-relation truncate.  We first open and grab exclusive
 531  * lock on all relations involved, checking permissions and otherwise
 532  * verifying that the relation is OK for truncation.  In CASCADE mode,
 533  * relations having FK references to the targeted relations are automatically
 534  * added to the group; in RESTRICT mode, we check that all FK references are
 535  * internal to the group that's being truncated.  Finally all the relations
 536  * are truncated and reindexed.
 537  */
 538 void
 539 ExecuteTruncate(TruncateStmt *stmt)
 540 {
 541         List       *rels = NIL;
 542         List       *directRelids = NIL;
 543         ListCell   *cell;
 544         Oid                     relid;
 545         Relation        rel;
 546
 547         /*
 548          * Open and exclusive-lock all the explicitly-specified relations
 549          */
 550         foreach(cell, stmt->relations)
 551         {
 552                 RangeVar   *rv = lfirst(cell);
 553
 554                 rel = heap_openrv(rv, AccessExclusiveLock);
 555                 rels = lappend(rels, rel);
 556                 directRelids = lappend_oid(directRelids, RelationGetRelid(rel));
 557         }
 558
 559         /*
 560          * In CASCADE mode, suck in all referencing relations as well.  This
 561          * requires multiple iterations to find indirectly-dependent relations.
 562          * At each phase, we need to exclusive-lock new rels before looking
 563          * for their dependencies, else we might miss something.
 564          */
 565         if (stmt->behavior == DROP_CASCADE)
 566         {
 567                 List   *relids = list_copy(directRelids);
 568
 569                 for (;;)
 570                 {
 571                         List   *newrelids;
 572
 573                         newrelids = heap_truncate_find_FKs(relids);
 574                         if (newrelids == NIL)
 575                                 break;                  /* nothing else to add */
 576
 577                         foreach(cell, newrelids)
 578                         {
 579                                 relid = lfirst_oid(cell);
 580                                 rel = heap_open(relid, AccessExclusiveLock);
 581                                 rels = lappend(rels, rel);
 582                                 relids = lappend_oid(relids, relid);
 583                         }
 584                 }
 585         }
 586
 587         /* now check all involved relations */
 588         foreach(cell, rels)
 589         {
 590                 rel = (Relation) lfirst(cell);
 591                 relid = RelationGetRelid(rel);
 592
 593                 /*
 594                  * If this table was added to the command by CASCADE, report it.
 595                  * We don't do this earlier because if we error out on one of the
 596                  * tables, it'd be confusing to list subsequently-added tables.
 597                  */
 598                 if (stmt->behavior == DROP_CASCADE &&
 599                         !list_member_oid(directRelids, relid))
 600                         ereport(NOTICE,
 601                                         (errmsg("truncate cascades to table \"%s\"",
 602                                                         RelationGetRelationName(rel))));
 603
 604                 /* Only allow truncate on regular tables */
 605                 if (rel->rd_rel->relkind != RELKIND_RELATION)
 606                         ereport(ERROR,
 607                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 608                                          errmsg("\"%s\" is not a table",
 609                                                         RelationGetRelationName(rel))));
 610
 611                 /* Permissions checks */
 612                 if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
 613                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 614                                                    RelationGetRelationName(rel));
 615
 616                 if (!allowSystemTableMods && IsSystemRelation(rel))
 617                         ereport(ERROR,
 618                                         (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 619                                          errmsg("permission denied: \"%s\" is a system catalog",
 620                                                         RelationGetRelationName(rel))));
 621
 622                 /*
 623                  * We can never allow truncation of shared or nailed-in-cache
 624                  * relations, because we can't support changing their relfilenode
 625                  * values.
 626                  */
 627                 if (rel->rd_rel->relisshared || rel->rd_isnailed)
 628                         ereport(ERROR,
 629                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 630                                          errmsg("cannot truncate system relation \"%s\"",
 631                                                         RelationGetRelationName(rel))));
 632
 633                 /*
 634                  * Don't allow truncate on temp tables of other backends ... their
 635                  * local buffer manager is not going to cope.
 636                  */
 637                 if (isOtherTempNamespace(RelationGetNamespace(rel)))
 638                         ereport(ERROR,
 639                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
 640                           errmsg("cannot truncate temporary tables of other sessions")));
 641         }
 642
 643         /*
 644          * Check foreign key references.  In CASCADE mode, this should be
 645          * unnecessary since we just pulled in all the references; but as
 646          * a cross-check, do it anyway if in an Assert-enabled build.
 647          */
 648 #ifdef USE_ASSERT_CHECKING
 649         heap_truncate_check_FKs(rels, false);
 650 #else
 651         if (stmt->behavior == DROP_RESTRICT)
 652                 heap_truncate_check_FKs(rels, false);
 653 #endif
 654
 655         /*
 656          * OK, truncate each table.
 657          */
 658         foreach(cell, rels)
 659         {
 660                 Oid                     heap_relid;
 661                 Oid                     toast_relid;
 662
 663                 rel = (Relation) lfirst(cell);
 664
 665                 /*
 666                  * Create a new empty storage file for the relation, and assign it as
 667                  * the relfilenode value.       The old storage file is scheduled for
 668                  * deletion at commit.
 669                  */
 670                 setNewRelfilenode(rel);
 671
 672                 heap_relid = RelationGetRelid(rel);
 673                 toast_relid = rel->rd_rel->reltoastrelid;
 674
 675                 heap_close(rel, NoLock);
 676
 677                 /*
 678                  * The same for the toast table, if any.
 679                  */
 680                 if (OidIsValid(toast_relid))
 681                 {
 682                         rel = relation_open(toast_relid, AccessExclusiveLock);
 683                         setNewRelfilenode(rel);
 684                         heap_close(rel, NoLock);
 685                 }
 686
 687                 /*
 688                  * Reconstruct the indexes to match, and we're done.
 689                  */
 690                 reindex_relation(heap_relid, true);
 691         }
 692 }
 693
 694 /*----------
 695  * MergeAttributes
 696  *              Returns new schema given initial schema and superclasses.
 697  *
 698  * Input arguments:
 699  * 'schema' is the column/attribute definition for the table. (It's a list
 700  *              of ColumnDef's.) It is destructively changed.
 701  * 'supers' is a list of names (as RangeVar nodes) of parent relations.
 702  * 'istemp' is TRUE if we are creating a temp relation.
 703  *
 704  * Output arguments:
 705  * 'supOids' receives a list of the OIDs of the parent relations.
 706  * 'supconstr' receives a list of constraints belonging to the parents,
 707  *              updated as necessary to be valid for the child.
 708  * 'supOidCount' is set to the number of parents that have OID columns.
 709  *
 710  * Return value:
 711  * Completed schema list.
 712  *
 713  * Notes:
 714  *        The order in which the attributes are inherited is very important.
 715  *        Intuitively, the inherited attributes should come first. If a table
 716  *        inherits from multiple parents, the order of those attributes are
 717  *        according to the order of the parents specified in CREATE TABLE.
 718  *
 719  *        Here's an example:
 720  *
 721  *              create table person (name text, age int4, location point);
 722  *              create table emp (salary int4, manager text) inherits(person);
 723  *              create table student (gpa float8) inherits (person);
 724  *              create table stud_emp (percent int4) inherits (emp, student);
 725  *
 726  *        The order of the attributes of stud_emp is:
 727  *
 728  *                                                      person {1:name, 2:age, 3:location}
 729  *                                                      /        \
 730  *                         {6:gpa}      student   emp {4:salary, 5:manager}
 731  *                                                      \        /
 732  *                                                 stud_emp {7:percent}
 733  *
 734  *         If the same attribute name appears multiple times, then it appears
 735  *         in the result table in the proper location for its first appearance.
 736  *
 737  *         Constraints (including NOT NULL constraints) for the child table
 738  *         are the union of all relevant constraints, from both the child schema
 739  *         and parent tables.
 740  *
 741  *         The default value for a child column is defined as:
 742  *              (1) If the child schema specifies a default, that value is used.
 743  *              (2) If neither the child nor any parent specifies a default, then
 744  *                      the column will not have a default.
 745  *              (3) If conflicting defaults are inherited from different parents
 746  *                      (and not overridden by the child), an error is raised.
 747  *              (4) Otherwise the inherited default is used.
 748  *              Rule (3) is new in Postgres 7.1; in earlier releases you got a
 749  *              rather arbitrary choice of which parent default to use.
 750  *----------
 751  */
 752 static List *
 753 MergeAttributes(List *schema, List *supers, bool istemp,
 754                                 List **supOids, List **supconstr, int *supOidCount)
 755 {
 756         ListCell   *entry;
 757         List       *inhSchema = NIL;
 758         List       *parentOids = NIL;
 759         List       *constraints = NIL;
 760         int                     parentsWithOids = 0;
 761         bool            have_bogus_defaults = false;
 762         char       *bogus_marker = "Bogus!";            /* marks conflicting defaults */
 763         int                     child_attno;
 764
 765         /*
 766          * Check for and reject tables with too many columns. We perform this
 767          * check relatively early for two reasons: (a) we don't run the risk of
 768          * overflowing an AttrNumber in subsequent code (b) an O(n^2) algorithm is
 769          * okay if we're processing <= 1600 columns, but could take minutes to
 770          * execute if the user attempts to create a table with hundreds of
 771          * thousands of columns.
 772          *
 773          * Note that we also need to check that any we do not exceed this figure
 774          * after including columns from inherited relations.
 775          */
 776         if (list_length(schema) > MaxHeapAttributeNumber)
 777                 ereport(ERROR,
 778                                 (errcode(ERRCODE_TOO_MANY_COLUMNS),
 779                                  errmsg("tables can have at most %d columns",
 780                                                 MaxHeapAttributeNumber)));
 781
 782         /*
 783          * Check for duplicate names in the explicit list of attributes.
 784          *
 785          * Although we might consider merging such entries in the same way that we
 786          * handle name conflicts for inherited attributes, it seems to make more
 787          * sense to assume such conflicts are errors.
 788          */
 789         foreach(entry, schema)
 790         {
 791                 ColumnDef  *coldef = lfirst(entry);
 792                 ListCell   *rest;
 793
 794                 for_each_cell(rest, lnext(entry))
 795                 {
 796                         ColumnDef  *restdef = lfirst(rest);
 797
 798                         if (strcmp(coldef->colname, restdef->colname) == 0)
 799                                 ereport(ERROR,
 800                                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
 801                                                  errmsg("column \"%s\" duplicated",
 802                                                                 coldef->colname)));
 803                 }
 804         }
 805
 806         /*
 807          * Scan the parents left-to-right, and merge their attributes to form a
 808          * list of inherited attributes (inhSchema).  Also check to see if we need
 809          * to inherit an OID column.
 810          */
 811         child_attno = 0;
 812         foreach(entry, supers)
 813         {
 814                 RangeVar   *parent = (RangeVar *) lfirst(entry);
 815                 Relation        relation;
 816                 TupleDesc       tupleDesc;
 817                 TupleConstr *constr;
 818                 AttrNumber *newattno;
 819                 AttrNumber      parent_attno;
 820
 821                 relation = heap_openrv(parent, AccessShareLock);
 822
 823                 if (relation->rd_rel->relkind != RELKIND_RELATION)
 824                         ereport(ERROR,
 825                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 826                                          errmsg("inherited relation \"%s\" is not a table",
 827                                                         parent->relname)));
 828                 /* Permanent rels cannot inherit from temporary ones */
 829                 if (!istemp && isTempNamespace(RelationGetNamespace(relation)))
 830                         ereport(ERROR,
 831                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 832                                          errmsg("cannot inherit from temporary relation \"%s\"",
 833                                                         parent->relname)));
 834
 835                 /*
 836                  * We should have an UNDER permission flag for this, but for now,
 837                  * demand that creator of a child table own the parent.
 838                  */
 839                 if (!pg_class_ownercheck(RelationGetRelid(relation), GetUserId()))
 840                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 841                                                    RelationGetRelationName(relation));
 842
 843                 /*
 844                  * Reject duplications in the list of parents.
 845                  */
 846                 if (list_member_oid(parentOids, RelationGetRelid(relation)))
 847                         ereport(ERROR,
 848                                         (errcode(ERRCODE_DUPLICATE_TABLE),
 849                                          errmsg("inherited relation \"%s\" duplicated",
 850                                                         parent->relname)));
 851
 852                 parentOids = lappend_oid(parentOids, RelationGetRelid(relation));
 853
 854                 if (relation->rd_rel->relhasoids)
 855                         parentsWithOids++;
 856
 857                 tupleDesc = RelationGetDescr(relation);
 858                 constr = tupleDesc->constr;
 859
 860                 /*
 861                  * newattno[] will contain the child-table attribute numbers for the
 862                  * attributes of this parent table.  (They are not the same for
 863                  * parents after the first one, nor if we have dropped columns.)
 864                  */
 865                 newattno = (AttrNumber *)
 866                         palloc(tupleDesc->natts * sizeof(AttrNumber));
 867
 868                 for (parent_attno = 1; parent_attno <= tupleDesc->natts;
 869                          parent_attno++)
 870                 {
 871                         Form_pg_attribute attribute = tupleDesc->attrs[parent_attno - 1];
 872                         char       *attributeName = NameStr(attribute->attname);
 873                         int                     exist_attno;
 874                         ColumnDef  *def;
 875                         TypeName   *typename;
 876
 877                         /*
 878                          * Ignore dropped columns in the parent.
 879                          */
 880                         if (attribute->attisdropped)
 881                         {
 882                                 /*
 883                                  * change_varattnos_of_a_node asserts that this is greater
 884                                  * than zero, so if anything tries to use it, we should find
 885                                  * out.
 886                                  */
 887                                 newattno[parent_attno - 1] = 0;
 888                                 continue;
 889                         }
 890
 891                         /*
 892                          * Does it conflict with some previously inherited column?
 893                          */
 894                         exist_attno = findAttrByName(attributeName, inhSchema);
 895                         if (exist_attno > 0)
 896                         {
 897                                 /*
 898                                  * Yes, try to merge the two column definitions. They must
 899                                  * have the same type and typmod.
 900                                  */
 901                                 ereport(NOTICE,
 902                                                 (errmsg("merging multiple inherited definitions of column \"%s\"",
 903                                                                 attributeName)));
 904                                 def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
 905                                 if (typenameTypeId(def->typename) != attribute->atttypid ||
 906                                         def->typename->typmod != attribute->atttypmod)
 907                                         ereport(ERROR,
 908                                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
 909                                                 errmsg("inherited column \"%s\" has a type conflict",
 910                                                            attributeName),
 911                                                          errdetail("%s versus %s",
 912                                                                            TypeNameToString(def->typename),
 913                                                                            format_type_be(attribute->atttypid))));
 914                                 def->inhcount++;
 915                                 /* Merge of NOT NULL constraints = OR 'em together */
 916                                 def->is_not_null |= attribute->attnotnull;
 917                                 /* Default and other constraints are handled below */
 918                                 newattno[parent_attno - 1] = exist_attno;
 919                         }
 920                         else
 921                         {
 922                                 /*
 923                                  * No, create a new inherited column
 924                                  */
 925                                 def = makeNode(ColumnDef);
 926                                 def->colname = pstrdup(attributeName);
 927                                 typename = makeNode(TypeName);
 928                                 typename->typeid = attribute->atttypid;
 929                                 typename->typmod = attribute->atttypmod;
 930                                 def->typename = typename;
 931                                 def->inhcount = 1;
 932                                 def->is_local = false;
 933                                 def->is_not_null = attribute->attnotnull;
 934                                 def->raw_default = NULL;
 935                                 def->cooked_default = NULL;
 936                                 def->constraints = NIL;
 937                                 def->support = NULL;
 938                                 inhSchema = lappend(inhSchema, def);
 939                                 newattno[parent_attno - 1] = ++child_attno;
 940                         }
 941
 942                         /*
 943                          * Copy default if any
 944                          */
 945                         if (attribute->atthasdef)
 946                         {
 947                                 char       *this_default = NULL;
 948                                 AttrDefault *attrdef;
 949                                 int                     i;
 950
 951                                 /* Find default in constraint structure */
 952                                 Assert(constr != NULL);
 953                                 attrdef = constr->defval;
 954                                 for (i = 0; i < constr->num_defval; i++)
 955                                 {
 956                                         if (attrdef[i].adnum == parent_attno)
 957                                         {
 958                                                 this_default = attrdef[i].adbin;
 959                                                 break;
 960                                         }
 961                                 }
 962                                 Assert(this_default != NULL);
 963
 964                                 /*
 965                                  * If default expr could contain any vars, we'd need to fix
 966                                  * 'em, but it can't; so default is ready to apply to child.
 967                                  *
 968                                  * If we already had a default from some prior parent, check
 969                                  * to see if they are the same.  If so, no problem; if not,
 970                                  * mark the column as having a bogus default. Below, we will
 971                                  * complain if the bogus default isn't overridden by the child
 972                                  * schema.
 973                                  */
 974                                 Assert(def->raw_default == NULL);
 975                                 if (def->cooked_default == NULL)
 976                                         def->cooked_default = pstrdup(this_default);
 977                                 else if (strcmp(def->cooked_default, this_default) != 0)
 978                                 {
 979                                         def->cooked_default = bogus_marker;
 980                                         have_bogus_defaults = true;
 981                                 }
 982                         }
 983                 }
 984
 985                 /*
 986                  * Now copy the constraints of this parent, adjusting attnos using the
 987                  * completed newattno[] map
 988                  */
 989                 if (constr && constr->num_check > 0)
 990                 {
 991                         ConstrCheck *check = constr->check;
 992                         int                     i;
 993
 994                         for (i = 0; i < constr->num_check; i++)
 995                         {
 996                                 Constraint *cdef = makeNode(Constraint);
 997                                 Node       *expr;
 998
 999                                 cdef->contype = CONSTR_CHECK;
1000                                 cdef->name = pstrdup(check[i].ccname);
1001                                 cdef->raw_expr = NULL;
1002                                 /* adjust varattnos of ccbin here */
1003                                 expr = stringToNode(check[i].ccbin);
1004                                 change_varattnos_of_a_node(expr, newattno);
1005                                 cdef->cooked_expr = nodeToString(expr);
1006                                 constraints = lappend(constraints, cdef);
1007                         }
1008                 }
1009
1010                 pfree(newattno);
1011
1012                 /*
1013                  * Close the parent rel, but keep our AccessShareLock on it until xact
1014                  * commit.      That will prevent someone else from deleting or ALTERing
1015                  * the parent before the child is committed.
1016                  */
1017                 heap_close(relation, NoLock);
1018         }
1019
1020         /*
1021          * If we had no inherited attributes, the result schema is just the
1022          * explicitly declared columns.  Otherwise, we need to merge the declared
1023          * columns into the inherited schema list.
1024          */
1025         if (inhSchema != NIL)
1026         {
1027                 foreach(entry, schema)
1028                 {
1029                         ColumnDef  *newdef = lfirst(entry);
1030                         char       *attributeName = newdef->colname;
1031                         int                     exist_attno;
1032
1033                         /*
1034                          * Does it conflict with some previously inherited column?
1035                          */
1036                         exist_attno = findAttrByName(attributeName, inhSchema);
1037                         if (exist_attno > 0)
1038                         {
1039                                 ColumnDef  *def;
1040
1041                                 /*
1042                                  * Yes, try to merge the two column definitions. They must
1043                                  * have the same type and typmod.
1044                                  */
1045                                 ereport(NOTICE,
1046                                    (errmsg("merging column \"%s\" with inherited definition",
1047                                                    attributeName)));
1048                                 def = (ColumnDef *) list_nth(inhSchema, exist_attno - 1);
1049                                 if (typenameTypeId(def->typename) != typenameTypeId(newdef->typename) ||
1050                                         def->typename->typmod != newdef->typename->typmod)
1051                                         ereport(ERROR,
1052                                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
1053                                                          errmsg("column \"%s\" has a type conflict",
1054                                                                         attributeName),
1055                                                          errdetail("%s versus %s",
1056                                                                            TypeNameToString(def->typename),
1057                                                                            TypeNameToString(newdef->typename))));
1058                                 /* Mark the column as locally defined */
1059                                 def->is_local = true;
1060                                 /* Merge of NOT NULL constraints = OR 'em together */
1061                                 def->is_not_null |= newdef->is_not_null;
1062                                 /* If new def has a default, override previous default */
1063                                 if (newdef->raw_default != NULL)
1064                                 {
1065                                         def->raw_default = newdef->raw_default;
1066                                         def->cooked_default = newdef->cooked_default;
1067                                 }
1068                         }
1069                         else
1070                         {
1071                                 /*
1072                                  * No, attach new column to result schema
1073                                  */
1074                                 inhSchema = lappend(inhSchema, newdef);
1075                         }
1076                 }
1077
1078                 schema = inhSchema;
1079
1080                 /*
1081                  * Check that we haven't exceeded the legal # of columns after merging
1082                  * in inherited columns.
1083                  */
1084                 if (list_length(schema) > MaxHeapAttributeNumber)
1085                         ereport(ERROR,
1086                                         (errcode(ERRCODE_TOO_MANY_COLUMNS),
1087                                          errmsg("tables can have at most %d columns",
1088                                                         MaxHeapAttributeNumber)));
1089         }
1090
1091         /*
1092          * If we found any conflicting parent default values, check to make sure
1093          * they were overridden by the child.
1094          */
1095         if (have_bogus_defaults)
1096         {
1097                 foreach(entry, schema)
1098                 {
1099                         ColumnDef  *def = lfirst(entry);
1100
1101                         if (def->cooked_default == bogus_marker)
1102                                 ereport(ERROR,
1103                                                 (errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
1104                                   errmsg("column \"%s\" inherits conflicting default values",
1105                                                  def->colname),
1106                                                  errhint("To resolve the conflict, specify a default explicitly.")));
1107                 }
1108         }
1109
1110         *supOids = parentOids;
1111         *supconstr = constraints;
1112         *supOidCount = parentsWithOids;
1113         return schema;
1114 }
1115
1116 /*
1117  * complementary static functions for MergeAttributes().
1118  *
1119  * Varattnos of pg_constraint.conbin must be rewritten when subclasses inherit
1120  * constraints from parent classes, since the inherited attributes could
1121  * be given different column numbers in multiple-inheritance cases.
1122  *
1123  * Note that the passed node tree is modified in place!
1124  */
1125 static bool
1126 change_varattnos_walker(Node *node, const AttrNumber *newattno)
1127 {
1128         if (node == NULL)
1129                 return false;
1130         if (IsA(node, Var))
1131         {
1132                 Var                *var = (Var *) node;
1133
1134                 if (var->varlevelsup == 0 && var->varno == 1 &&
1135                         var->varattno > 0)
1136                 {
1137                         /*
1138                          * ??? the following may be a problem when the node is multiply
1139                          * referenced though stringToNode() doesn't create such a node
1140                          * currently.
1141                          */
1142                         Assert(newattno[var->varattno - 1] > 0);
1143                         var->varattno = newattno[var->varattno - 1];
1144                 }
1145                 return false;
1146         }
1147         return expression_tree_walker(node, change_varattnos_walker,
1148                                                                   (void *) newattno);
1149 }
1150
1151 static bool
1152 change_varattnos_of_a_node(Node *node, const AttrNumber *newattno)
1153 {
1154         return change_varattnos_walker(node, newattno);
1155 }
1156
1157 /*
1158  * StoreCatalogInheritance
1159  *              Updates the system catalogs with proper inheritance information.
1160  *
1161  * supers is a list of the OIDs of the new relation's direct ancestors.
1162  */
1163 static void
1164 StoreCatalogInheritance(Oid relationId, List *supers)
1165 {
1166         Relation        relation;
1167         TupleDesc       desc;
1168         int16           seqNumber;
1169         ListCell   *entry;
1170         HeapTuple       tuple;
1171
1172         /*
1173          * sanity checks
1174          */
1175         AssertArg(OidIsValid(relationId));
1176
1177         if (supers == NIL)
1178                 return;
1179
1180         /*
1181          * Store INHERITS information in pg_inherits using direct ancestors only.
1182          * Also enter dependencies on the direct ancestors, and make sure they are
1183          * marked with relhassubclass = true.
1184          *
1185          * (Once upon a time, both direct and indirect ancestors were found here
1186          * and then entered into pg_ipl.  Since that catalog doesn't exist
1187          * anymore, there's no need to look for indirect ancestors.)
1188          */
1189         relation = heap_open(InheritsRelationId, RowExclusiveLock);
1190         desc = RelationGetDescr(relation);
1191
1192         seqNumber = 1;
1193         foreach(entry, supers)
1194         {
1195                 Oid                     parentOid = lfirst_oid(entry);
1196                 Datum           datum[Natts_pg_inherits];
1197                 char            nullarr[Natts_pg_inherits];
1198                 ObjectAddress childobject,
1199                                         parentobject;
1200
1201                 datum[0] = ObjectIdGetDatum(relationId);                /* inhrel */
1202                 datum[1] = ObjectIdGetDatum(parentOid); /* inhparent */
1203                 datum[2] = Int16GetDatum(seqNumber);    /* inhseqno */
1204
1205                 nullarr[0] = ' ';
1206                 nullarr[1] = ' ';
1207                 nullarr[2] = ' ';
1208
1209                 tuple = heap_formtuple(desc, datum, nullarr);
1210
1211                 simple_heap_insert(relation, tuple);
1212
1213                 CatalogUpdateIndexes(relation, tuple);
1214
1215                 heap_freetuple(tuple);
1216
1217                 /*
1218                  * Store a dependency too
1219                  */
1220                 parentobject.classId = RelationRelationId;
1221                 parentobject.objectId = parentOid;
1222                 parentobject.objectSubId = 0;
1223                 childobject.classId = RelationRelationId;
1224                 childobject.objectId = relationId;
1225                 childobject.objectSubId = 0;
1226
1227                 recordDependencyOn(&childobject, &parentobject, DEPENDENCY_NORMAL);
1228
1229                 /*
1230                  * Mark the parent as having subclasses.
1231                  */
1232                 setRelhassubclassInRelation(parentOid, true);
1233
1234                 seqNumber += 1;
1235         }
1236
1237         heap_close(relation, RowExclusiveLock);
1238 }
1239
1240 /*
1241  * Look for an existing schema entry with the given name.
1242  *
1243  * Returns the index (starting with 1) if attribute already exists in schema,
1244  * 0 if it doesn't.
1245  */
1246 static int
1247 findAttrByName(const char *attributeName, List *schema)
1248 {
1249         ListCell   *s;
1250         int                     i = 1;
1251
1252         foreach(s, schema)
1253         {
1254                 ColumnDef  *def = lfirst(s);
1255
1256                 if (strcmp(attributeName, def->colname) == 0)
1257                         return i;
1258
1259                 i++;
1260         }
1261         return 0;
1262 }
1263
1264 /*
1265  * Update a relation's pg_class.relhassubclass entry to the given value
1266  */
1267 static void
1268 setRelhassubclassInRelation(Oid relationId, bool relhassubclass)
1269 {
1270         Relation        relationRelation;
1271         HeapTuple       tuple;
1272         Form_pg_class classtuple;
1273
1274         /*
1275          * Fetch a modifiable copy of the tuple, modify it, update pg_class.
1276          *
1277          * If the tuple already has the right relhassubclass setting, we don't
1278          * need to update it, but we still need to issue an SI inval message.
1279          */
1280         relationRelation = heap_open(RelationRelationId, RowExclusiveLock);
1281         tuple = SearchSysCacheCopy(RELOID,
1282                                                            ObjectIdGetDatum(relationId),
1283                                                            0, 0, 0);
1284         if (!HeapTupleIsValid(tuple))
1285                 elog(ERROR, "cache lookup failed for relation %u", relationId);
1286         classtuple = (Form_pg_class) GETSTRUCT(tuple);
1287
1288         if (classtuple->relhassubclass != relhassubclass)
1289         {
1290                 classtuple->relhassubclass = relhassubclass;
1291                 simple_heap_update(relationRelation, &tuple->t_self, tuple);
1292
1293                 /* keep the catalog indexes up to date */
1294                 CatalogUpdateIndexes(relationRelation, tuple);
1295         }
1296         else
1297         {
1298                 /* no need to change tuple, but force relcache rebuild anyway */
1299                 CacheInvalidateRelcacheByTuple(tuple);
1300         }
1301
1302         heap_freetuple(tuple);
1303         heap_close(relationRelation, RowExclusiveLock);
1304 }
1305
1306
1307 /*
1308  *              renameatt               - changes the name of a attribute in a relation
1309  *
1310  *              Attname attribute is changed in attribute catalog.
1311  *              No record of the previous attname is kept (correct?).
1312  *
1313  *              get proper relrelation from relation catalog (if not arg)
1314  *              scan attribute catalog
1315  *                              for name conflict (within rel)
1316  *                              for original attribute (if not arg)
1317  *              modify attname in attribute tuple
1318  *              insert modified attribute in attribute catalog
1319  *              delete original attribute from attribute catalog
1320  */
1321 void
1322 renameatt(Oid myrelid,
1323                   const char *oldattname,
1324                   const char *newattname,
1325                   bool recurse,
1326                   bool recursing)
1327 {
1328         Relation        targetrelation;
1329         Relation        attrelation;
1330         HeapTuple       atttup;
1331         Form_pg_attribute attform;
1332         int                     attnum;
1333         List       *indexoidlist;
1334         ListCell   *indexoidscan;
1335
1336         /*
1337          * Grab an exclusive lock on the target table, which we will NOT release
1338          * until end of transaction.
1339          */
1340         targetrelation = relation_open(myrelid, AccessExclusiveLock);
1341
1342         /*
1343          * permissions checking.  this would normally be done in utility.c, but
1344          * this particular routine is recursive.
1345          *
1346          * normally, only the owner of a class can change its schema.
1347          */
1348         if (!pg_class_ownercheck(myrelid, GetUserId()))
1349                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
1350                                            RelationGetRelationName(targetrelation));
1351         if (!allowSystemTableMods && IsSystemRelation(targetrelation))
1352                 ereport(ERROR,
1353                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
1354                                  errmsg("permission denied: \"%s\" is a system catalog",
1355                                                 RelationGetRelationName(targetrelation))));
1356
1357         /*
1358          * if the 'recurse' flag is set then we are supposed to rename this
1359          * attribute in all classes that inherit from 'relname' (as well as in
1360          * 'relname').
1361          *
1362          * any permissions or problems with duplicate attributes will cause the
1363          * whole transaction to abort, which is what we want -- all or nothing.
1364          */
1365         if (recurse)
1366         {
1367                 ListCell   *child;
1368                 List       *children;
1369
1370                 /* this routine is actually in the planner */
1371                 children = find_all_inheritors(myrelid);
1372
1373                 /*
1374                  * find_all_inheritors does the recursive search of the inheritance
1375                  * hierarchy, so all we have to do is process all of the relids in the
1376                  * list that it returns.
1377                  */
1378                 foreach(child, children)
1379                 {
1380                         Oid                     childrelid = lfirst_oid(child);
1381
1382                         if (childrelid == myrelid)
1383                                 continue;
1384                         /* note we need not recurse again */
1385                         renameatt(childrelid, oldattname, newattname, false, true);
1386                 }
1387         }
1388         else
1389         {
1390                 /*
1391                  * If we are told not to recurse, there had better not be any child
1392                  * tables; else the rename would put them out of step.
1393                  */
1394                 if (!recursing &&
1395                         find_inheritance_children(myrelid) != NIL)
1396                         ereport(ERROR,
1397                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
1398                                          errmsg("inherited column \"%s\" must be renamed in child tables too",
1399                                                         oldattname)));
1400         }
1401
1402         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
1403
1404         atttup = SearchSysCacheCopyAttName(myrelid, oldattname);
1405         if (!HeapTupleIsValid(atttup))
1406                 ereport(ERROR,
1407                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
1408                                  errmsg("column \"%s\" does not exist",
1409                                                 oldattname)));
1410         attform = (Form_pg_attribute) GETSTRUCT(atttup);
1411
1412         attnum = attform->attnum;
1413         if (attnum <= 0)
1414                 ereport(ERROR,
1415                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1416                                  errmsg("cannot rename system column \"%s\"",
1417                                                 oldattname)));
1418
1419         /*
1420          * if the attribute is inherited, forbid the renaming, unless we are
1421          * already inside a recursive rename.
1422          */
1423         if (attform->attinhcount > 0 && !recursing)
1424                 ereport(ERROR,
1425                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
1426                                  errmsg("cannot rename inherited column \"%s\"",
1427                                                 oldattname)));
1428
1429         /* should not already exist */
1430         /* this test is deliberately not attisdropped-aware */
1431         if (SearchSysCacheExists(ATTNAME,
1432                                                          ObjectIdGetDatum(myrelid),
1433                                                          PointerGetDatum(newattname),
1434                                                          0, 0))
1435                 ereport(ERROR,
1436                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
1437                                  errmsg("column \"%s\" of relation \"%s\" already exists",
1438                                           newattname, RelationGetRelationName(targetrelation))));
1439
1440         namestrcpy(&(attform->attname), newattname);
1441
1442         simple_heap_update(attrelation, &atttup->t_self, atttup);
1443
1444         /* keep system catalog indexes current */
1445         CatalogUpdateIndexes(attrelation, atttup);
1446
1447         heap_freetuple(atttup);
1448
1449         /*
1450          * Update column names of indexes that refer to the column being renamed.
1451          */
1452         indexoidlist = RelationGetIndexList(targetrelation);
1453
1454         foreach(indexoidscan, indexoidlist)
1455         {
1456                 Oid                     indexoid = lfirst_oid(indexoidscan);
1457                 HeapTuple       indextup;
1458                 Form_pg_index indexform;
1459                 int                     i;
1460
1461                 /*
1462                  * Scan through index columns to see if there's any simple index
1463                  * entries for this attribute.  We ignore expressional entries.
1464                  */
1465                 indextup = SearchSysCache(INDEXRELID,
1466                                                                   ObjectIdGetDatum(indexoid),
1467                                                                   0, 0, 0);
1468                 if (!HeapTupleIsValid(indextup))
1469                         elog(ERROR, "cache lookup failed for index %u", indexoid);
1470                 indexform = (Form_pg_index) GETSTRUCT(indextup);
1471
1472                 for (i = 0; i < indexform->indnatts; i++)
1473                 {
1474                         if (attnum != indexform->indkey.values[i])
1475                                 continue;
1476
1477                         /*
1478                          * Found one, rename it.
1479                          */
1480                         atttup = SearchSysCacheCopy(ATTNUM,
1481                                                                                 ObjectIdGetDatum(indexoid),
1482                                                                                 Int16GetDatum(i + 1),
1483                                                                                 0, 0);
1484                         if (!HeapTupleIsValid(atttup))
1485                                 continue;               /* should we raise an error? */
1486
1487                         /*
1488                          * Update the (copied) attribute tuple.
1489                          */
1490                         namestrcpy(&(((Form_pg_attribute) GETSTRUCT(atttup))->attname),
1491                                            newattname);
1492
1493                         simple_heap_update(attrelation, &atttup->t_self, atttup);
1494
1495                         /* keep system catalog indexes current */
1496                         CatalogUpdateIndexes(attrelation, atttup);
1497
1498                         heap_freetuple(atttup);
1499                 }
1500
1501                 ReleaseSysCache(indextup);
1502         }
1503
1504         list_free(indexoidlist);
1505
1506         heap_close(attrelation, RowExclusiveLock);
1507
1508         /*
1509          * Update att name in any RI triggers associated with the relation.
1510          */
1511         if (targetrelation->rd_rel->reltriggers > 0)
1512         {
1513                 /* update tgargs column reference where att is primary key */
1514                 update_ri_trigger_args(RelationGetRelid(targetrelation),
1515                                                            oldattname, newattname,
1516                                                            false, false);
1517                 /* update tgargs column reference where att is foreign key */
1518                 update_ri_trigger_args(RelationGetRelid(targetrelation),
1519                                                            oldattname, newattname,
1520                                                            true, false);
1521         }
1522
1523         relation_close(targetrelation, NoLock);         /* close rel but keep lock */
1524 }
1525
1526 /*
1527  *              renamerel               - change the name of a relation
1528  *
1529  *              XXX - When renaming sequences, we don't bother to modify the
1530  *                        sequence name that is stored within the sequence itself
1531  *                        (this would cause problems with MVCC). In the future,
1532  *                        the sequence name should probably be removed from the
1533  *                        sequence, AFAIK there's no need for it to be there.
1534  */
1535 void
1536 renamerel(Oid myrelid, const char *newrelname)
1537 {
1538         Relation        targetrelation;
1539         Relation        relrelation;    /* for RELATION relation */
1540         HeapTuple       reltup;
1541         Oid                     namespaceId;
1542         char       *oldrelname;
1543         char            relkind;
1544         bool            relhastriggers;
1545
1546         /*
1547          * Grab an exclusive lock on the target table or index, which we will NOT
1548          * release until end of transaction.
1549          */
1550         targetrelation = relation_open(myrelid, AccessExclusiveLock);
1551
1552         oldrelname = pstrdup(RelationGetRelationName(targetrelation));
1553         namespaceId = RelationGetNamespace(targetrelation);
1554
1555         if (!allowSystemTableMods && IsSystemRelation(targetrelation))
1556                 ereport(ERROR,
1557                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
1558                                  errmsg("permission denied: \"%s\" is a system catalog",
1559                                                 RelationGetRelationName(targetrelation))));
1560
1561         relkind = targetrelation->rd_rel->relkind;
1562         relhastriggers = (targetrelation->rd_rel->reltriggers > 0);
1563
1564         /*
1565          * Find relation's pg_class tuple, and make sure newrelname isn't in use.
1566          */
1567         relrelation = heap_open(RelationRelationId, RowExclusiveLock);
1568
1569         reltup = SearchSysCacheCopy(RELOID,
1570                                                                 PointerGetDatum(myrelid),
1571                                                                 0, 0, 0);
1572         if (!HeapTupleIsValid(reltup))          /* shouldn't happen */
1573                 elog(ERROR, "cache lookup failed for relation %u", myrelid);
1574
1575         if (get_relname_relid(newrelname, namespaceId) != InvalidOid)
1576                 ereport(ERROR,
1577                                 (errcode(ERRCODE_DUPLICATE_TABLE),
1578                                  errmsg("relation \"%s\" already exists",
1579                                                 newrelname)));
1580
1581         /*
1582          * Update pg_class tuple with new relname.      (Scribbling on reltup is OK
1583          * because it's a copy...)
1584          */
1585         namestrcpy(&(((Form_pg_class) GETSTRUCT(reltup))->relname), newrelname);
1586
1587         simple_heap_update(relrelation, &reltup->t_self, reltup);
1588
1589         /* keep the system catalog indexes current */
1590         CatalogUpdateIndexes(relrelation, reltup);
1591
1592         heap_freetuple(reltup);
1593         heap_close(relrelation, RowExclusiveLock);
1594
1595         /*
1596          * Also rename the associated type, if any.
1597          */
1598         if (relkind != RELKIND_INDEX)
1599                 TypeRename(oldrelname, namespaceId, newrelname);
1600
1601         /*
1602          * Update rel name in any RI triggers associated with the relation.
1603          */
1604         if (relhastriggers)
1605         {
1606                 /* update tgargs where relname is primary key */
1607                 update_ri_trigger_args(myrelid,
1608                                                            oldrelname,
1609                                                            newrelname,
1610                                                            false, true);
1611                 /* update tgargs where relname is foreign key */
1612                 update_ri_trigger_args(myrelid,
1613                                                            oldrelname,
1614                                                            newrelname,
1615                                                            true, true);
1616         }
1617
1618         /*
1619          * Close rel, but keep exclusive lock!
1620          */
1621         relation_close(targetrelation, NoLock);
1622 }
1623
1624 /*
1625  * Scan pg_trigger for RI triggers that are on the specified relation
1626  * (if fk_scan is false) or have it as the tgconstrrel (if fk_scan
1627  * is true).  Update RI trigger args fields matching oldname to contain
1628  * newname instead.  If update_relname is true, examine the relname
1629  * fields; otherwise examine the attname fields.
1630  */
1631 static void
1632 update_ri_trigger_args(Oid relid,
1633                                            const char *oldname,
1634                                            const char *newname,
1635                                            bool fk_scan,
1636                                            bool update_relname)
1637 {
1638         Relation        tgrel;
1639         ScanKeyData skey[1];
1640         SysScanDesc trigscan;
1641         HeapTuple       tuple;
1642         Datum           values[Natts_pg_trigger];
1643         char            nulls[Natts_pg_trigger];
1644         char            replaces[Natts_pg_trigger];
1645
1646         tgrel = heap_open(TriggerRelationId, RowExclusiveLock);
1647         if (fk_scan)
1648         {
1649                 ScanKeyInit(&skey[0],
1650                                         Anum_pg_trigger_tgconstrrelid,
1651                                         BTEqualStrategyNumber, F_OIDEQ,
1652                                         ObjectIdGetDatum(relid));
1653                 trigscan = systable_beginscan(tgrel, TriggerConstrRelidIndexId,
1654                                                                           true, SnapshotNow,
1655                                                                           1, skey);
1656         }
1657         else
1658         {
1659                 ScanKeyInit(&skey[0],
1660                                         Anum_pg_trigger_tgrelid,
1661                                         BTEqualStrategyNumber, F_OIDEQ,
1662                                         ObjectIdGetDatum(relid));
1663                 trigscan = systable_beginscan(tgrel, TriggerRelidNameIndexId,
1664                                                                           true, SnapshotNow,
1665                                                                           1, skey);
1666         }
1667
1668         while ((tuple = systable_getnext(trigscan)) != NULL)
1669         {
1670                 Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
1671                 bytea      *val;
1672                 bytea      *newtgargs;
1673                 bool            isnull;
1674                 int                     tg_type;
1675                 bool            examine_pk;
1676                 bool            changed;
1677                 int                     tgnargs;
1678                 int                     i;
1679                 int                     newlen;
1680                 const char *arga[RI_MAX_ARGUMENTS];
1681                 const char *argp;
1682
1683                 tg_type = RI_FKey_trigger_type(pg_trigger->tgfoid);
1684                 if (tg_type == RI_TRIGGER_NONE)
1685                 {
1686                         /* Not an RI trigger, forget it */
1687                         continue;
1688                 }
1689
1690                 /*
1691                  * It is an RI trigger, so parse the tgargs bytea.
1692                  *
1693                  * NB: we assume the field will never be compressed or moved out of
1694                  * line; so does trigger.c ...
1695                  */
1696                 tgnargs = pg_trigger->tgnargs;
1697                 val = (bytea *)
1698                         DatumGetPointer(fastgetattr(tuple,
1699                                                                                 Anum_pg_trigger_tgargs,
1700                                                                                 tgrel->rd_att, &isnull));
1701                 if (isnull || tgnargs < RI_FIRST_ATTNAME_ARGNO ||
1702                         tgnargs > RI_MAX_ARGUMENTS)
1703                 {
1704                         /* This probably shouldn't happen, but ignore busted triggers */
1705                         continue;
1706                 }
1707                 argp = (const char *) VARDATA(val);
1708                 for (i = 0; i < tgnargs; i++)
1709                 {
1710                         arga[i] = argp;
1711                         argp += strlen(argp) + 1;
1712                 }
1713
1714                 /*
1715                  * Figure out which item(s) to look at.  If the trigger is primary-key
1716                  * type and attached to my rel, I should look at the PK fields; if it
1717                  * is foreign-key type and attached to my rel, I should look at the FK
1718                  * fields.      But the opposite rule holds when examining triggers found
1719                  * by tgconstrrel search.
1720                  */
1721                 examine_pk = (tg_type == RI_TRIGGER_PK) == (!fk_scan);
1722
1723                 changed = false;
1724                 if (update_relname)
1725                 {
1726                         /* Change the relname if needed */
1727                         i = examine_pk ? RI_PK_RELNAME_ARGNO : RI_FK_RELNAME_ARGNO;
1728                         if (strcmp(arga[i], oldname) == 0)
1729                         {
1730                                 arga[i] = newname;
1731                                 changed = true;
1732                         }
1733                 }
1734                 else
1735                 {
1736                         /* Change attname(s) if needed */
1737                         i = examine_pk ? RI_FIRST_ATTNAME_ARGNO + RI_KEYPAIR_PK_IDX :
1738                                 RI_FIRST_ATTNAME_ARGNO + RI_KEYPAIR_FK_IDX;
1739                         for (; i < tgnargs; i += 2)
1740                         {
1741                                 if (strcmp(arga[i], oldname) == 0)
1742                                 {
1743                                         arga[i] = newname;
1744                                         changed = true;
1745                                 }
1746                         }
1747                 }
1748
1749                 if (!changed)
1750                 {
1751                         /* Don't need to update this tuple */
1752                         continue;
1753                 }
1754
1755                 /*
1756                  * Construct modified tgargs bytea.
1757                  */
1758                 newlen = VARHDRSZ;
1759                 for (i = 0; i < tgnargs; i++)
1760                         newlen += strlen(arga[i]) + 1;
1761                 newtgargs = (bytea *) palloc(newlen);
1762                 VARATT_SIZEP(newtgargs) = newlen;
1763                 newlen = VARHDRSZ;
1764                 for (i = 0; i < tgnargs; i++)
1765                 {
1766                         strcpy(((char *) newtgargs) + newlen, arga[i]);
1767                         newlen += strlen(arga[i]) + 1;
1768                 }
1769
1770                 /*
1771                  * Build modified tuple.
1772                  */
1773                 for (i = 0; i < Natts_pg_trigger; i++)
1774                 {
1775                         values[i] = (Datum) 0;
1776                         replaces[i] = ' ';
1777                         nulls[i] = ' ';
1778                 }
1779                 values[Anum_pg_trigger_tgargs - 1] = PointerGetDatum(newtgargs);
1780                 replaces[Anum_pg_trigger_tgargs - 1] = 'r';
1781
1782                 tuple = heap_modifytuple(tuple, RelationGetDescr(tgrel), values, nulls, replaces);
1783
1784                 /*
1785                  * Update pg_trigger and its indexes
1786                  */
1787                 simple_heap_update(tgrel, &tuple->t_self, tuple);
1788
1789                 CatalogUpdateIndexes(tgrel, tuple);
1790
1791                 /*
1792                  * Invalidate trigger's relation's relcache entry so that other
1793                  * backends (and this one too!) are sent SI message to make them
1794                  * rebuild relcache entries.  (Ideally this should happen
1795                  * automatically...)
1796                  *
1797                  * We can skip this for triggers on relid itself, since that relcache
1798                  * flush will happen anyway due to the table or column rename.  We
1799                  * just need to catch the far ends of RI relationships.
1800                  */
1801                 pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
1802                 if (pg_trigger->tgrelid != relid)
1803                         CacheInvalidateRelcacheByRelid(pg_trigger->tgrelid);
1804
1805                 /* free up our scratch memory */
1806                 pfree(newtgargs);
1807                 heap_freetuple(tuple);
1808         }
1809
1810         systable_endscan(trigscan);
1811
1812         heap_close(tgrel, RowExclusiveLock);
1813
1814         /*
1815          * Increment cmd counter to make updates visible; this is needed in case
1816          * the same tuple has to be updated again by next pass (can happen in case
1817          * of a self-referential FK relationship).
1818          */
1819         CommandCounterIncrement();
1820 }
1821
1822 /*
1823  * AlterTable
1824  *              Execute ALTER TABLE, which can be a list of subcommands
1825  *
1826  * ALTER TABLE is performed in three phases:
1827  *              1. Examine subcommands and perform pre-transformation checking.
1828  *              2. Update system catalogs.
1829  *              3. Scan table(s) to check new constraints, and optionally recopy
1830  *                 the data into new table(s).
1831  * Phase 3 is not performed unless one or more of the subcommands requires
1832  * it.  The intention of this design is to allow multiple independent
1833  * updates of the table schema to be performed with only one pass over the
1834  * data.
1835  *
1836  * ATPrepCmd performs phase 1.  A "work queue" entry is created for
1837  * each table to be affected (there may be multiple affected tables if the
1838  * commands traverse a table inheritance hierarchy).  Also we do preliminary
1839  * validation of the subcommands, including parse transformation of those
1840  * expressions that need to be evaluated with respect to the old table
1841  * schema.
1842  *
1843  * ATRewriteCatalogs performs phase 2 for each affected table (note that
1844  * phases 2 and 3 do no explicit recursion, since phase 1 already did it).
1845  * Certain subcommands need to be performed before others to avoid
1846  * unnecessary conflicts; for example, DROP COLUMN should come before
1847  * ADD COLUMN.  Therefore phase 1 divides the subcommands into multiple
1848  * lists, one for each logical "pass" of phase 2.
1849  *
1850  * ATRewriteTables performs phase 3 for those tables that need it.
1851  *
1852  * Thanks to the magic of MVCC, an error anywhere along the way rolls back
1853  * the whole operation; we don't have to do anything special to clean up.
1854  */
1855 void
1856 AlterTable(AlterTableStmt *stmt)
1857 {
1858         ATController(relation_openrv(stmt->relation, AccessExclusiveLock),
1859                                  stmt->cmds,
1860                                  interpretInhOption(stmt->relation->inhOpt));
1861 }
1862
1863 /*
1864  * AlterTableInternal
1865  *
1866  * ALTER TABLE with target specified by OID
1867  */
1868 void
1869 AlterTableInternal(Oid relid, List *cmds, bool recurse)
1870 {
1871         ATController(relation_open(relid, AccessExclusiveLock),
1872                                  cmds,
1873                                  recurse);
1874 }
1875
1876 static void
1877 ATController(Relation rel, List *cmds, bool recurse)
1878 {
1879         List       *wqueue = NIL;
1880         ListCell   *lcmd;
1881
1882         /* Phase 1: preliminary examination of commands, create work queue */
1883         foreach(lcmd, cmds)
1884         {
1885                 AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
1886
1887                 ATPrepCmd(&wqueue, rel, cmd, recurse, false);
1888         }
1889
1890         /* Close the relation, but keep lock until commit */
1891         relation_close(rel, NoLock);
1892
1893         /* Phase 2: update system catalogs */
1894         ATRewriteCatalogs(&wqueue);
1895
1896         /* Phase 3: scan/rewrite tables as needed */
1897         ATRewriteTables(&wqueue);
1898 }
1899
1900 /*
1901  * ATPrepCmd
1902  *
1903  * Traffic cop for ALTER TABLE Phase 1 operations, including simple
1904  * recursion and permission checks.
1905  *
1906  * Caller must have acquired AccessExclusiveLock on relation already.
1907  * This lock should be held until commit.
1908  */
1909 static void
1910 ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
1911                   bool recurse, bool recursing)
1912 {
1913         AlteredTableInfo *tab;
1914         int                     pass;
1915
1916         /* Find or create work queue entry for this table */
1917         tab = ATGetQueueEntry(wqueue, rel);
1918
1919         /*
1920          * Copy the original subcommand for each table.  This avoids conflicts
1921          * when different child tables need to make different parse
1922          * transformations (for example, the same column may have different column
1923          * numbers in different children).
1924          */
1925         cmd = copyObject(cmd);
1926
1927         /*
1928          * Do permissions checking, recursion to child tables if needed, and any
1929          * additional phase-1 processing needed.
1930          */
1931         switch (cmd->subtype)
1932         {
1933                 case AT_AddColumn:              /* ADD COLUMN */
1934                         ATSimplePermissions(rel, false);
1935                         /* Performs own recursion */
1936                         ATPrepAddColumn(wqueue, rel, recurse, cmd);
1937                         pass = AT_PASS_ADD_COL;
1938                         break;
1939                 case AT_ColumnDefault:  /* ALTER COLUMN DEFAULT */
1940
1941                         /*
1942                          * We allow defaults on views so that INSERT into a view can have
1943                          * default-ish behavior.  This works because the rewriter
1944                          * substitutes default values into INSERTs before it expands
1945                          * rules.
1946                          */
1947                         ATSimplePermissions(rel, true);
1948                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
1949                         /* No command-specific prep needed */
1950                         pass = AT_PASS_ADD_CONSTR;
1951                         break;
1952                 case AT_DropNotNull:    /* ALTER COLUMN DROP NOT NULL */
1953                         ATSimplePermissions(rel, false);
1954                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
1955                         /* No command-specific prep needed */
1956                         pass = AT_PASS_DROP;
1957                         break;
1958                 case AT_SetNotNull:             /* ALTER COLUMN SET NOT NULL */
1959                         ATSimplePermissions(rel, false);
1960                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
1961                         /* No command-specific prep needed */
1962                         pass = AT_PASS_ADD_CONSTR;
1963                         break;
1964                 case AT_SetStatistics:  /* ALTER COLUMN STATISTICS */
1965                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
1966                         /* Performs own permission checks */
1967                         ATPrepSetStatistics(rel, cmd->name, cmd->def);
1968                         pass = AT_PASS_COL_ATTRS;
1969                         break;
1970                 case AT_SetStorage:             /* ALTER COLUMN STORAGE */
1971                         ATSimplePermissions(rel, false);
1972                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
1973                         /* No command-specific prep needed */
1974                         pass = AT_PASS_COL_ATTRS;
1975                         break;
1976                 case AT_DropColumn:             /* DROP COLUMN */
1977                         ATSimplePermissions(rel, false);
1978                         /* Recursion occurs during execution phase */
1979                         /* No command-specific prep needed except saving recurse flag */
1980                         if (recurse)
1981                                 cmd->subtype = AT_DropColumnRecurse;
1982                         pass = AT_PASS_DROP;
1983                         break;
1984                 case AT_AddIndex:               /* ADD INDEX */
1985                         ATSimplePermissions(rel, false);
1986                         /* This command never recurses */
1987                         /* No command-specific prep needed */
1988                         pass = AT_PASS_ADD_INDEX;
1989                         break;
1990                 case AT_AddConstraint:  /* ADD CONSTRAINT */
1991                         ATSimplePermissions(rel, false);
1992
1993                         /*
1994                          * Currently we recurse only for CHECK constraints, never for
1995                          * foreign-key constraints.  UNIQUE/PKEY constraints won't be seen
1996                          * here.
1997                          */
1998                         if (IsA(cmd->def, Constraint))
1999                                 ATSimpleRecursion(wqueue, rel, cmd, recurse);
2000                         /* No command-specific prep needed */
2001                         pass = AT_PASS_ADD_CONSTR;
2002                         break;
2003                 case AT_DropConstraint: /* DROP CONSTRAINT */
2004                         ATSimplePermissions(rel, false);
2005                         /* Performs own recursion */
2006                         ATPrepDropConstraint(wqueue, rel, recurse, cmd);
2007                         pass = AT_PASS_DROP;
2008                         break;
2009                 case AT_DropConstraintQuietly:  /* DROP CONSTRAINT for child */
2010                         ATSimplePermissions(rel, false);
2011                         ATSimpleRecursion(wqueue, rel, cmd, recurse);
2012                         /* No command-specific prep needed */
2013                         pass = AT_PASS_DROP;
2014                         break;
2015                 case AT_AlterColumnType:                /* ALTER COLUMN TYPE */
2016                         ATSimplePermissions(rel, false);
2017                         /* Performs own recursion */
2018                         ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd);
2019                         pass = AT_PASS_ALTER_TYPE;
2020                         break;
2021                 case AT_ToastTable:             /* CREATE TOAST TABLE */
2022                         ATSimplePermissions(rel, false);
2023                         /* This command never recurses */
2024                         /* No command-specific prep needed */
2025                         pass = AT_PASS_MISC;
2026                         break;
2027                 case AT_ChangeOwner:    /* ALTER OWNER */
2028                         /* This command never recurses */
2029                         /* No command-specific prep needed */
2030                         pass = AT_PASS_MISC;
2031                         break;
2032                 case AT_ClusterOn:              /* CLUSTER ON */
2033                 case AT_DropCluster:    /* SET WITHOUT CLUSTER */
2034                         ATSimplePermissions(rel, false);
2035                         /* These commands never recurse */
2036                         /* No command-specific prep needed */
2037                         pass = AT_PASS_MISC;
2038                         break;
2039                 case AT_DropOids:               /* SET WITHOUT OIDS */
2040                         ATSimplePermissions(rel, false);
2041                         /* Performs own recursion */
2042                         if (rel->rd_rel->relhasoids)
2043                         {
2044                                 AlterTableCmd *dropCmd = makeNode(AlterTableCmd);
2045
2046                                 dropCmd->subtype = AT_DropColumn;
2047                                 dropCmd->name = pstrdup("oid");
2048                                 dropCmd->behavior = cmd->behavior;
2049                                 ATPrepCmd(wqueue, rel, dropCmd, recurse, false);
2050                         }
2051                         pass = AT_PASS_DROP;
2052                         break;
2053                 case AT_SetTableSpace:  /* SET TABLESPACE */
2054                         /* This command never recurses */
2055                         ATPrepSetTableSpace(tab, rel, cmd->name);
2056                         pass = AT_PASS_MISC;    /* doesn't actually matter */
2057                         break;
2058                 case AT_EnableTrig:             /* ENABLE TRIGGER variants */
2059                 case AT_EnableTrigAll:
2060                 case AT_EnableTrigUser:
2061                 case AT_DisableTrig:    /* DISABLE TRIGGER variants */
2062                 case AT_DisableTrigAll:
2063                 case AT_DisableTrigUser:
2064                         ATSimplePermissions(rel, false);
2065                         /* These commands never recurse */
2066                         /* No command-specific prep needed */
2067                         pass = AT_PASS_MISC;
2068                         break;
2069                 default:                                /* oops */
2070                         elog(ERROR, "unrecognized alter table type: %d",
2071                                  (int) cmd->subtype);
2072                         pass = 0;                       /* keep compiler quiet */
2073                         break;
2074         }
2075
2076         /* Add the subcommand to the appropriate list for phase 2 */
2077         tab->subcmds[pass] = lappend(tab->subcmds[pass], cmd);
2078 }
2079
2080 /*
2081  * ATRewriteCatalogs
2082  *
2083  * Traffic cop for ALTER TABLE Phase 2 operations.      Subcommands are
2084  * dispatched in a "safe" execution order (designed to avoid unnecessary
2085  * conflicts).
2086  */
2087 static void
2088 ATRewriteCatalogs(List **wqueue)
2089 {
2090         int                     pass;
2091         ListCell   *ltab;
2092
2093         /*
2094          * We process all the tables "in parallel", one pass at a time.  This is
2095          * needed because we may have to propagate work from one table to another
2096          * (specifically, ALTER TYPE on a foreign key's PK has to dispatch the
2097          * re-adding of the foreign key constraint to the other table).  Work can
2098          * only be propagated into later passes, however.
2099          */
2100         for (pass = 0; pass < AT_NUM_PASSES; pass++)
2101         {
2102                 /* Go through each table that needs to be processed */
2103                 foreach(ltab, *wqueue)
2104                 {
2105                         AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2106                         List       *subcmds = tab->subcmds[pass];
2107                         Relation        rel;
2108                         ListCell   *lcmd;
2109
2110                         if (subcmds == NIL)
2111                                 continue;
2112
2113                         /*
2114                          * Exclusive lock was obtained by phase 1, needn't get it again
2115                          */
2116                         rel = relation_open(tab->relid, NoLock);
2117
2118                         foreach(lcmd, subcmds)
2119                                 ATExecCmd(tab, rel, (AlterTableCmd *) lfirst(lcmd));
2120
2121                         /*
2122                          * After the ALTER TYPE pass, do cleanup work (this is not done in
2123                          * ATExecAlterColumnType since it should be done only once if
2124                          * multiple columns of a table are altered).
2125                          */
2126                         if (pass == AT_PASS_ALTER_TYPE)
2127                                 ATPostAlterTypeCleanup(wqueue, tab);
2128
2129                         relation_close(rel, NoLock);
2130                 }
2131         }
2132
2133         /*
2134          * Do an implicit CREATE TOAST TABLE if we executed any subcommands that
2135          * might have added a column or changed column storage.
2136          */
2137         foreach(ltab, *wqueue)
2138         {
2139                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2140
2141                 if (tab->relkind == RELKIND_RELATION &&
2142                         (tab->subcmds[AT_PASS_ADD_COL] ||
2143                          tab->subcmds[AT_PASS_ALTER_TYPE] ||
2144                          tab->subcmds[AT_PASS_COL_ATTRS]))
2145                         AlterTableCreateToastTable(tab->relid, true);
2146         }
2147 }
2148
2149 /*
2150  * ATExecCmd: dispatch a subcommand to appropriate execution routine
2151  */
2152 static void
2153 ATExecCmd(AlteredTableInfo *tab, Relation rel, AlterTableCmd *cmd)
2154 {
2155         switch (cmd->subtype)
2156         {
2157                 case AT_AddColumn:              /* ADD COLUMN */
2158                         ATExecAddColumn(tab, rel, (ColumnDef *) cmd->def);
2159                         break;
2160                 case AT_ColumnDefault:  /* ALTER COLUMN DEFAULT */
2161                         ATExecColumnDefault(rel, cmd->name, cmd->def);
2162                         break;
2163                 case AT_DropNotNull:    /* ALTER COLUMN DROP NOT NULL */
2164                         ATExecDropNotNull(rel, cmd->name);
2165                         break;
2166                 case AT_SetNotNull:             /* ALTER COLUMN SET NOT NULL */
2167                         ATExecSetNotNull(tab, rel, cmd->name);
2168                         break;
2169                 case AT_SetStatistics:  /* ALTER COLUMN STATISTICS */
2170                         ATExecSetStatistics(rel, cmd->name, cmd->def);
2171                         break;
2172                 case AT_SetStorage:             /* ALTER COLUMN STORAGE */
2173                         ATExecSetStorage(rel, cmd->name, cmd->def);
2174                         break;
2175                 case AT_DropColumn:             /* DROP COLUMN */
2176                         ATExecDropColumn(rel, cmd->name, cmd->behavior, false, false);
2177                         break;
2178                 case AT_DropColumnRecurse:              /* DROP COLUMN with recursion */
2179                         ATExecDropColumn(rel, cmd->name, cmd->behavior, true, false);
2180                         break;
2181                 case AT_AddIndex:               /* ADD INDEX */
2182                         ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, false);
2183                         break;
2184                 case AT_ReAddIndex:             /* ADD INDEX */
2185                         ATExecAddIndex(tab, rel, (IndexStmt *) cmd->def, true);
2186                         break;
2187                 case AT_AddConstraint:  /* ADD CONSTRAINT */
2188                         ATExecAddConstraint(tab, rel, cmd->def);
2189                         break;
2190                 case AT_DropConstraint: /* DROP CONSTRAINT */
2191                         ATExecDropConstraint(rel, cmd->name, cmd->behavior, false);
2192                         break;
2193                 case AT_DropConstraintQuietly:  /* DROP CONSTRAINT for child */
2194                         ATExecDropConstraint(rel, cmd->name, cmd->behavior, true);
2195                         break;
2196                 case AT_AlterColumnType:                /* ALTER COLUMN TYPE */
2197                         ATExecAlterColumnType(tab, rel, cmd->name, (TypeName *) cmd->def);
2198                         break;
2199                 case AT_ToastTable:             /* CREATE TOAST TABLE */
2200                         AlterTableCreateToastTable(RelationGetRelid(rel), false);
2201                         break;
2202                 case AT_ChangeOwner:    /* ALTER OWNER */
2203                         ATExecChangeOwner(RelationGetRelid(rel),
2204                                                           get_roleid_checked(cmd->name),
2205                                                           false);
2206                         break;
2207                 case AT_ClusterOn:              /* CLUSTER ON */
2208                         ATExecClusterOn(rel, cmd->name);
2209                         break;
2210                 case AT_DropCluster:    /* SET WITHOUT CLUSTER */
2211                         ATExecDropCluster(rel);
2212                         break;
2213                 case AT_DropOids:               /* SET WITHOUT OIDS */
2214
2215                         /*
2216                          * Nothing to do here; we'll have generated a DropColumn
2217                          * subcommand to do the real work
2218                          */
2219                         break;
2220                 case AT_SetTableSpace:  /* SET TABLESPACE */
2221
2222                         /*
2223                          * Nothing to do here; Phase 3 does the work
2224                          */
2225                         break;
2226                 case AT_EnableTrig:             /* ENABLE TRIGGER name */
2227                         ATExecEnableDisableTrigger(rel, cmd->name, true, false);
2228                         break;
2229                 case AT_DisableTrig:    /* DISABLE TRIGGER name */
2230                         ATExecEnableDisableTrigger(rel, cmd->name, false, false);
2231                         break;
2232                 case AT_EnableTrigAll:  /* ENABLE TRIGGER ALL */
2233                         ATExecEnableDisableTrigger(rel, NULL, true, false);
2234                         break;
2235                 case AT_DisableTrigAll: /* DISABLE TRIGGER ALL */
2236                         ATExecEnableDisableTrigger(rel, NULL, false, false);
2237                         break;
2238                 case AT_EnableTrigUser: /* ENABLE TRIGGER USER */
2239                         ATExecEnableDisableTrigger(rel, NULL, true, true);
2240                         break;
2241                 case AT_DisableTrigUser:                /* DISABLE TRIGGER USER */
2242                         ATExecEnableDisableTrigger(rel, NULL, false, true);
2243                         break;
2244                 default:                                /* oops */
2245                         elog(ERROR, "unrecognized alter table type: %d",
2246                                  (int) cmd->subtype);
2247                         break;
2248         }
2249
2250         /*
2251          * Bump the command counter to ensure the next subcommand in the sequence
2252          * can see the changes so far
2253          */
2254         CommandCounterIncrement();
2255 }
2256
2257 /*
2258  * ATRewriteTables: ALTER TABLE phase 3
2259  */
2260 static void
2261 ATRewriteTables(List **wqueue)
2262 {
2263         ListCell   *ltab;
2264
2265         /* Go through each table that needs to be checked or rewritten */
2266         foreach(ltab, *wqueue)
2267         {
2268                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2269
2270                 /*
2271                  * We only need to rewrite the table if at least one column needs to
2272                  * be recomputed.
2273                  */
2274                 if (tab->newvals != NIL)
2275                 {
2276                         /* Build a temporary relation and copy data */
2277                         Oid                     OIDNewHeap;
2278                         char            NewHeapName[NAMEDATALEN];
2279                         Oid                     NewTableSpace;
2280                         Relation        OldHeap;
2281                         ObjectAddress object;
2282
2283                         OldHeap = heap_open(tab->relid, NoLock);
2284
2285                         /*
2286                          * We can never allow rewriting of shared or nailed-in-cache
2287                          * relations, because we can't support changing their relfilenode
2288                          * values.
2289                          */
2290                         if (OldHeap->rd_rel->relisshared || OldHeap->rd_isnailed)
2291                                 ereport(ERROR,
2292                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2293                                                  errmsg("cannot rewrite system relation \"%s\"",
2294                                                                 RelationGetRelationName(OldHeap))));
2295
2296                         /*
2297                          * Don't allow rewrite on temp tables of other backends ... their
2298                          * local buffer manager is not going to cope.
2299                          */
2300                         if (isOtherTempNamespace(RelationGetNamespace(OldHeap)))
2301                                 ereport(ERROR,
2302                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2303                                 errmsg("cannot rewrite temporary tables of other sessions")));
2304
2305                         /*
2306                          * Select destination tablespace (same as original unless user
2307                          * requested a change)
2308                          */
2309                         if (tab->newTableSpace)
2310                                 NewTableSpace = tab->newTableSpace;
2311                         else
2312                                 NewTableSpace = OldHeap->rd_rel->reltablespace;
2313
2314                         heap_close(OldHeap, NoLock);
2315
2316                         /*
2317                          * Create the new heap, using a temporary name in the same
2318                          * namespace as the existing table.  NOTE: there is some risk of
2319                          * collision with user relnames.  Working around this seems more
2320                          * trouble than it's worth; in particular, we can't create the new
2321                          * heap in a different namespace from the old, or we will have
2322                          * problems with the TEMP status of temp tables.
2323                          */
2324                         snprintf(NewHeapName, sizeof(NewHeapName),
2325                                          "pg_temp_%u", tab->relid);
2326
2327                         OIDNewHeap = make_new_heap(tab->relid, NewHeapName, NewTableSpace);
2328
2329                         /*
2330                          * Copy the heap data into the new table with the desired
2331                          * modifications, and test the current data within the table
2332                          * against new constraints generated by ALTER TABLE commands.
2333                          */
2334                         ATRewriteTable(tab, OIDNewHeap);
2335
2336                         /* Swap the physical files of the old and new heaps. */
2337                         swap_relation_files(tab->relid, OIDNewHeap);
2338
2339                         CommandCounterIncrement();
2340
2341                         /* Destroy new heap with old filenode */
2342                         object.classId = RelationRelationId;
2343                         object.objectId = OIDNewHeap;
2344                         object.objectSubId = 0;
2345
2346                         /*
2347                          * The new relation is local to our transaction and we know
2348                          * nothing depends on it, so DROP_RESTRICT should be OK.
2349                          */
2350                         performDeletion(&object, DROP_RESTRICT);
2351                         /* performDeletion does CommandCounterIncrement at end */
2352
2353                         /*
2354                          * Rebuild each index on the relation (but not the toast table,
2355                          * which is all-new anyway).  We do not need
2356                          * CommandCounterIncrement() because reindex_relation does it.
2357                          */
2358                         reindex_relation(tab->relid, false);
2359                 }
2360                 else
2361                 {
2362                         /*
2363                          * Test the current data within the table against new constraints
2364                          * generated by ALTER TABLE commands, but don't rebuild data.
2365                          */
2366                         if (tab->constraints != NIL)
2367                                 ATRewriteTable(tab, InvalidOid);
2368
2369                         /*
2370                          * If we had SET TABLESPACE but no reason to reconstruct tuples,
2371                          * just do a block-by-block copy.
2372                          */
2373                         if (tab->newTableSpace)
2374                                 ATExecSetTableSpace(tab->relid, tab->newTableSpace);
2375                 }
2376         }
2377
2378         /*
2379          * Foreign key constraints are checked in a final pass, since (a) it's
2380          * generally best to examine each one separately, and (b) it's at least
2381          * theoretically possible that we have changed both relations of the
2382          * foreign key, and we'd better have finished both rewrites before we try
2383          * to read the tables.
2384          */
2385         foreach(ltab, *wqueue)
2386         {
2387                 AlteredTableInfo *tab = (AlteredTableInfo *) lfirst(ltab);
2388                 Relation        rel = NULL;
2389                 ListCell   *lcon;
2390
2391                 foreach(lcon, tab->constraints)
2392                 {
2393                         NewConstraint *con = lfirst(lcon);
2394
2395                         if (con->contype == CONSTR_FOREIGN)
2396                         {
2397                                 FkConstraint *fkconstraint = (FkConstraint *) con->qual;
2398                                 Relation        refrel;
2399
2400                                 if (rel == NULL)
2401                                 {
2402                                         /* Long since locked, no need for another */
2403                                         rel = heap_open(tab->relid, NoLock);
2404                                 }
2405
2406                                 refrel = heap_open(con->refrelid, RowShareLock);
2407
2408                                 validateForeignKeyConstraint(fkconstraint, rel, refrel);
2409
2410                                 heap_close(refrel, NoLock);
2411                         }
2412                 }
2413
2414                 if (rel)
2415                         heap_close(rel, NoLock);
2416         }
2417 }
2418
2419 /*
2420  * ATRewriteTable: scan or rewrite one table
2421  *
2422  * OIDNewHeap is InvalidOid if we don't need to rewrite
2423  */
2424 static void
2425 ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap)
2426 {
2427         Relation        oldrel;
2428         Relation        newrel;
2429         TupleDesc       oldTupDesc;
2430         TupleDesc       newTupDesc;
2431         bool            needscan = false;
2432         int                     i;
2433         ListCell   *l;
2434         EState     *estate;
2435
2436         /*
2437          * Open the relation(s).  We have surely already locked the existing
2438          * table.
2439          */
2440         oldrel = heap_open(tab->relid, NoLock);
2441         oldTupDesc = tab->oldDesc;
2442         newTupDesc = RelationGetDescr(oldrel);          /* includes all mods */
2443
2444         if (OidIsValid(OIDNewHeap))
2445                 newrel = heap_open(OIDNewHeap, AccessExclusiveLock);
2446         else
2447                 newrel = NULL;
2448
2449         /*
2450          * If we need to rewrite the table, the operation has to be propagated to
2451          * tables that use this table's rowtype as a column type.
2452          *
2453          * (Eventually this will probably become true for scans as well, but at
2454          * the moment a composite type does not enforce any constraints, so it's
2455          * not necessary/appropriate to enforce them just during ALTER.)
2456          */
2457         if (newrel)
2458                 find_composite_type_dependencies(oldrel->rd_rel->reltype,
2459                                                                                  RelationGetRelationName(oldrel));
2460
2461         /*
2462          * Generate the constraint and default execution states
2463          */
2464
2465         estate = CreateExecutorState();
2466
2467         /* Build the needed expression execution states */
2468         foreach(l, tab->constraints)
2469         {
2470                 NewConstraint *con = lfirst(l);
2471
2472                 switch (con->contype)
2473                 {
2474                         case CONSTR_CHECK:
2475                                 needscan = true;
2476                                 con->qualstate = (List *)
2477                                         ExecPrepareExpr((Expr *) con->qual, estate);
2478                                 break;
2479                         case CONSTR_FOREIGN:
2480                                 /* Nothing to do here */
2481                                 break;
2482                         case CONSTR_NOTNULL:
2483                                 needscan = true;
2484                                 break;
2485                         default:
2486                                 elog(ERROR, "unrecognized constraint type: %d",
2487                                          (int) con->contype);
2488                 }
2489         }
2490
2491         foreach(l, tab->newvals)
2492         {
2493                 NewColumnValue *ex = lfirst(l);
2494
2495                 needscan = true;
2496
2497                 ex->exprstate = ExecPrepareExpr((Expr *) ex->expr, estate);
2498         }
2499
2500         if (needscan)
2501         {
2502                 ExprContext *econtext;
2503                 Datum      *values;
2504                 bool       *isnull;
2505                 TupleTableSlot *oldslot;
2506                 TupleTableSlot *newslot;
2507                 HeapScanDesc scan;
2508                 HeapTuple       tuple;
2509                 MemoryContext oldCxt;
2510                 List       *dropped_attrs = NIL;
2511                 ListCell   *lc;
2512
2513                 econtext = GetPerTupleExprContext(estate);
2514
2515                 /*
2516                  * Make tuple slots for old and new tuples.  Note that even when the
2517                  * tuples are the same, the tupDescs might not be (consider ADD COLUMN
2518                  * without a default).
2519                  */
2520                 oldslot = MakeSingleTupleTableSlot(oldTupDesc);
2521                 newslot = MakeSingleTupleTableSlot(newTupDesc);
2522
2523                 /* Preallocate values/isnull arrays */
2524                 i = Max(newTupDesc->natts, oldTupDesc->natts);
2525                 values = (Datum *) palloc(i * sizeof(Datum));
2526                 isnull = (bool *) palloc(i * sizeof(bool));
2527                 memset(values, 0, i * sizeof(Datum));
2528                 memset(isnull, true, i * sizeof(bool));
2529
2530                 /*
2531                  * Any attributes that are dropped according to the new tuple
2532                  * descriptor can be set to NULL. We precompute the list of dropped
2533                  * attributes to avoid needing to do so in the per-tuple loop.
2534                  */
2535                 for (i = 0; i < newTupDesc->natts; i++)
2536                 {
2537                         if (newTupDesc->attrs[i]->attisdropped)
2538                                 dropped_attrs = lappend_int(dropped_attrs, i);
2539                 }
2540
2541                 /*
2542                  * Scan through the rows, generating a new row if needed and then
2543                  * checking all the constraints.
2544                  */
2545                 scan = heap_beginscan(oldrel, SnapshotNow, 0, NULL);
2546
2547                 /*
2548                  * Switch to per-tuple memory context and reset it for each tuple
2549                  * produced, so we don't leak memory.
2550                  */
2551                 oldCxt = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
2552
2553                 while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
2554                 {
2555                         if (newrel)
2556                         {
2557                                 Oid                     tupOid = InvalidOid;
2558
2559                                 /* Extract data from old tuple */
2560                                 heap_deform_tuple(tuple, oldTupDesc, values, isnull);
2561                                 if (oldTupDesc->tdhasoid)
2562                                         tupOid = HeapTupleGetOid(tuple);
2563
2564                                 /* Set dropped attributes to null in new tuple */
2565                                 foreach(lc, dropped_attrs)
2566                                         isnull[lfirst_int(lc)] = true;
2567
2568                                 /*
2569                                  * Process supplied expressions to replace selected columns.
2570                                  * Expression inputs come from the old tuple.
2571                                  */
2572                                 ExecStoreTuple(tuple, oldslot, InvalidBuffer, false);
2573                                 econtext->ecxt_scantuple = oldslot;
2574
2575                                 foreach(l, tab->newvals)
2576                                 {
2577                                         NewColumnValue *ex = lfirst(l);
2578
2579                                         values[ex->attnum - 1] = ExecEvalExpr(ex->exprstate,
2580                                                                                                                   econtext,
2581                                                                                                          &isnull[ex->attnum - 1],
2582                                                                                                                   NULL);
2583                                 }
2584
2585                                 /*
2586                                  * Form the new tuple. Note that we don't explicitly pfree it,
2587                                  * since the per-tuple memory context will be reset shortly.
2588                                  */
2589                                 tuple = heap_form_tuple(newTupDesc, values, isnull);
2590
2591                                 /* Preserve OID, if any */
2592                                 if (newTupDesc->tdhasoid)
2593                                         HeapTupleSetOid(tuple, tupOid);
2594                         }
2595
2596                         /* Now check any constraints on the possibly-changed tuple */
2597                         ExecStoreTuple(tuple, newslot, InvalidBuffer, false);
2598                         econtext->ecxt_scantuple = newslot;
2599
2600                         foreach(l, tab->constraints)
2601                         {
2602                                 NewConstraint *con = lfirst(l);
2603
2604                                 switch (con->contype)
2605                                 {
2606                                         case CONSTR_CHECK:
2607                                                 if (!ExecQual(con->qualstate, econtext, true))
2608                                                         ereport(ERROR,
2609                                                                         (errcode(ERRCODE_CHECK_VIOLATION),
2610                                                                          errmsg("check constraint \"%s\" is violated by some row",
2611                                                                                         con->name)));
2612                                                 break;
2613                                         case CONSTR_NOTNULL:
2614                                                 {
2615                                                         Datum           d;
2616                                                         bool            isnull;
2617
2618                                                         d = heap_getattr(tuple, con->attnum, newTupDesc,
2619                                                                                          &isnull);
2620                                                         if (isnull)
2621                                                                 ereport(ERROR,
2622                                                                                 (errcode(ERRCODE_NOT_NULL_VIOLATION),
2623                                                                  errmsg("column \"%s\" contains null values",
2624                                                                                 get_attname(tab->relid,
2625                                                                                                         con->attnum))));
2626                                                 }
2627                                                 break;
2628                                         case CONSTR_FOREIGN:
2629                                                 /* Nothing to do here */
2630                                                 break;
2631                                         default:
2632                                                 elog(ERROR, "unrecognized constraint type: %d",
2633                                                          (int) con->contype);
2634                                 }
2635                         }
2636
2637                         /* Write the tuple out to the new relation */
2638                         if (newrel)
2639                                 simple_heap_insert(newrel, tuple);
2640
2641                         ResetExprContext(econtext);
2642
2643                         CHECK_FOR_INTERRUPTS();
2644                 }
2645
2646                 MemoryContextSwitchTo(oldCxt);
2647                 heap_endscan(scan);
2648         }
2649
2650         FreeExecutorState(estate);
2651
2652         heap_close(oldrel, NoLock);
2653         if (newrel)
2654                 heap_close(newrel, NoLock);
2655 }
2656
2657 /*
2658  * ATGetQueueEntry: find or create an entry in the ALTER TABLE work queue
2659  */
2660 static AlteredTableInfo *
2661 ATGetQueueEntry(List **wqueue, Relation rel)
2662 {
2663         Oid                     relid = RelationGetRelid(rel);
2664         AlteredTableInfo *tab;
2665         ListCell   *ltab;
2666
2667         foreach(ltab, *wqueue)
2668         {
2669                 tab = (AlteredTableInfo *) lfirst(ltab);
2670                 if (tab->relid == relid)
2671                         return tab;
2672         }
2673
2674         /*
2675          * Not there, so add it.  Note that we make a copy of the relation's
2676          * existing descriptor before anything interesting can happen to it.
2677          */
2678         tab = (AlteredTableInfo *) palloc0(sizeof(AlteredTableInfo));
2679         tab->relid = relid;
2680         tab->relkind = rel->rd_rel->relkind;
2681         tab->oldDesc = CreateTupleDescCopy(RelationGetDescr(rel));
2682
2683         *wqueue = lappend(*wqueue, tab);
2684
2685         return tab;
2686 }
2687
2688 /*
2689  * ATSimplePermissions
2690  *
2691  * - Ensure that it is a relation (or possibly a view)
2692  * - Ensure this user is the owner
2693  * - Ensure that it is not a system table
2694  */
2695 static void
2696 ATSimplePermissions(Relation rel, bool allowView)
2697 {
2698         if (rel->rd_rel->relkind != RELKIND_RELATION)
2699         {
2700                 if (allowView)
2701                 {
2702                         if (rel->rd_rel->relkind != RELKIND_VIEW)
2703                                 ereport(ERROR,
2704                                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2705                                                  errmsg("\"%s\" is not a table or view",
2706                                                                 RelationGetRelationName(rel))));
2707                 }
2708                 else
2709                         ereport(ERROR,
2710                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
2711                                          errmsg("\"%s\" is not a table",
2712                                                         RelationGetRelationName(rel))));
2713         }
2714
2715         /* Permissions checks */
2716         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
2717                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
2718                                            RelationGetRelationName(rel));
2719
2720         if (!allowSystemTableMods && IsSystemRelation(rel))
2721                 ereport(ERROR,
2722                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
2723                                  errmsg("permission denied: \"%s\" is a system catalog",
2724                                                 RelationGetRelationName(rel))));
2725 }
2726
2727 /*
2728  * ATSimpleRecursion
2729  *
2730  * Simple table recursion sufficient for most ALTER TABLE operations.
2731  * All direct and indirect children are processed in an unspecified order.
2732  * Note that if a child inherits from the original table via multiple
2733  * inheritance paths, it will be visited just once.
2734  */
2735 static void
2736 ATSimpleRecursion(List **wqueue, Relation rel,
2737                                   AlterTableCmd *cmd, bool recurse)
2738 {
2739         /*
2740          * Propagate to children if desired.  Non-table relations never have
2741          * children, so no need to search in that case.
2742          */
2743         if (recurse && rel->rd_rel->relkind == RELKIND_RELATION)
2744         {
2745                 Oid                     relid = RelationGetRelid(rel);
2746                 ListCell   *child;
2747                 List       *children;
2748
2749                 /* this routine is actually in the planner */
2750                 children = find_all_inheritors(relid);
2751
2752                 /*
2753                  * find_all_inheritors does the recursive search of the inheritance
2754                  * hierarchy, so all we have to do is process all of the relids in the
2755                  * list that it returns.
2756                  */
2757                 foreach(child, children)
2758                 {
2759                         Oid                     childrelid = lfirst_oid(child);
2760                         Relation        childrel;
2761
2762                         if (childrelid == relid)
2763                                 continue;
2764                         childrel = relation_open(childrelid, AccessExclusiveLock);
2765                         ATPrepCmd(wqueue, childrel, cmd, false, true);
2766                         relation_close(childrel, NoLock);
2767                 }
2768         }
2769 }
2770
2771 /*
2772  * ATOneLevelRecursion
2773  *
2774  * Here, we visit only direct inheritance children.  It is expected that
2775  * the command's prep routine will recurse again to find indirect children.
2776  * When using this technique, a multiply-inheriting child will be visited
2777  * multiple times.
2778  */
2779 static void
2780 ATOneLevelRecursion(List **wqueue, Relation rel,
2781                                         AlterTableCmd *cmd)
2782 {
2783         Oid                     relid = RelationGetRelid(rel);
2784         ListCell   *child;
2785         List       *children;
2786
2787         /* this routine is actually in the planner */
2788         children = find_inheritance_children(relid);
2789
2790         foreach(child, children)
2791         {
2792                 Oid                     childrelid = lfirst_oid(child);
2793                 Relation        childrel;
2794
2795                 childrel = relation_open(childrelid, AccessExclusiveLock);
2796                 ATPrepCmd(wqueue, childrel, cmd, true, true);
2797                 relation_close(childrel, NoLock);
2798         }
2799 }
2800
2801
2802 /*
2803  * find_composite_type_dependencies
2804  *
2805  * Check to see if a table's rowtype is being used as a column in some
2806  * other table (possibly nested several levels deep in composite types!).
2807  * Eventually, we'd like to propagate the check or rewrite operation
2808  * into other such tables, but for now, just error out if we find any.
2809  *
2810  * We assume that functions and views depending on the type are not reasons
2811  * to reject the ALTER.  (How safe is this really?)
2812  */
2813 static void
2814 find_composite_type_dependencies(Oid typeOid, const char *origTblName)
2815 {
2816         Relation        depRel;
2817         ScanKeyData key[2];
2818         SysScanDesc depScan;
2819         HeapTuple       depTup;
2820
2821         /*
2822          * We scan pg_depend to find those things that depend on the rowtype. (We
2823          * assume we can ignore refobjsubid for a rowtype.)
2824          */
2825         depRel = heap_open(DependRelationId, AccessShareLock);
2826
2827         ScanKeyInit(&key[0],
2828                                 Anum_pg_depend_refclassid,
2829                                 BTEqualStrategyNumber, F_OIDEQ,
2830                                 ObjectIdGetDatum(TypeRelationId));
2831         ScanKeyInit(&key[1],
2832                                 Anum_pg_depend_refobjid,
2833                                 BTEqualStrategyNumber, F_OIDEQ,
2834                                 ObjectIdGetDatum(typeOid));
2835
2836         depScan = systable_beginscan(depRel, DependReferenceIndexId, true,
2837                                                                  SnapshotNow, 2, key);
2838
2839         while (HeapTupleIsValid(depTup = systable_getnext(depScan)))
2840         {
2841                 Form_pg_depend pg_depend = (Form_pg_depend) GETSTRUCT(depTup);
2842                 Relation        rel;
2843                 Form_pg_attribute att;
2844
2845                 /* Ignore dependees that aren't user columns of relations */
2846                 /* (we assume system columns are never of rowtypes) */
2847                 if (pg_depend->classid != RelationRelationId ||
2848                         pg_depend->objsubid <= 0)
2849                         continue;
2850
2851                 rel = relation_open(pg_depend->objid, AccessShareLock);
2852                 att = rel->rd_att->attrs[pg_depend->objsubid - 1];
2853
2854                 if (rel->rd_rel->relkind == RELKIND_RELATION)
2855                 {
2856                         ereport(ERROR,
2857                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2858                                          errmsg("cannot alter table \"%s\" because column \"%s\".\"%s\" uses its rowtype",
2859                                                         origTblName,
2860                                                         RelationGetRelationName(rel),
2861                                                         NameStr(att->attname))));
2862                 }
2863                 else if (OidIsValid(rel->rd_rel->reltype))
2864                 {
2865                         /*
2866                          * A view or composite type itself isn't a problem, but we must
2867                          * recursively check for indirect dependencies via its rowtype.
2868                          */
2869                         find_composite_type_dependencies(rel->rd_rel->reltype,
2870                                                                                          origTblName);
2871                 }
2872
2873                 relation_close(rel, AccessShareLock);
2874         }
2875
2876         systable_endscan(depScan);
2877
2878         relation_close(depRel, AccessShareLock);
2879 }
2880
2881
2882 /*
2883  * ALTER TABLE ADD COLUMN
2884  *
2885  * Adds an additional attribute to a relation making the assumption that
2886  * CHECK, NOT NULL, and FOREIGN KEY constraints will be removed from the
2887  * AT_AddColumn AlterTableCmd by analyze.c and added as independent
2888  * AlterTableCmd's.
2889  */
2890 static void
2891 ATPrepAddColumn(List **wqueue, Relation rel, bool recurse,
2892                                 AlterTableCmd *cmd)
2893 {
2894         /*
2895          * Recurse to add the column to child classes, if requested.
2896          *
2897          * We must recurse one level at a time, so that multiply-inheriting
2898          * children are visited the right number of times and end up with the
2899          * right attinhcount.
2900          */
2901         if (recurse)
2902         {
2903                 AlterTableCmd *childCmd = copyObject(cmd);
2904                 ColumnDef  *colDefChild = (ColumnDef *) childCmd->def;
2905
2906                 /* Child should see column as singly inherited */
2907                 colDefChild->inhcount = 1;
2908                 colDefChild->is_local = false;
2909                 /* and don't make a support dependency on the child */
2910                 colDefChild->support = NULL;
2911
2912                 ATOneLevelRecursion(wqueue, rel, childCmd);
2913         }
2914         else
2915         {
2916                 /*
2917                  * If we are told not to recurse, there had better not be any child
2918                  * tables; else the addition would put them out of step.
2919                  */
2920                 if (find_inheritance_children(RelationGetRelid(rel)) != NIL)
2921                         ereport(ERROR,
2922                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
2923                                          errmsg("column must be added to child tables too")));
2924         }
2925 }
2926
2927 static void
2928 ATExecAddColumn(AlteredTableInfo *tab, Relation rel,
2929                                 ColumnDef *colDef)
2930 {
2931         Oid                     myrelid = RelationGetRelid(rel);
2932         Relation        pgclass,
2933                                 attrdesc;
2934         HeapTuple       reltup;
2935         HeapTuple       attributeTuple;
2936         Form_pg_attribute attribute;
2937         FormData_pg_attribute attributeD;
2938         int                     i;
2939         int                     minattnum,
2940                                 maxatts;
2941         HeapTuple       typeTuple;
2942         Oid                     typeOid;
2943         Form_pg_type tform;
2944         Expr       *defval;
2945
2946         attrdesc = heap_open(AttributeRelationId, RowExclusiveLock);
2947
2948         /*
2949          * Are we adding the column to a recursion child?  If so, check whether to
2950          * merge with an existing definition for the column.
2951          */
2952         if (colDef->inhcount > 0)
2953         {
2954                 HeapTuple       tuple;
2955
2956                 /* Does child already have a column by this name? */
2957                 tuple = SearchSysCacheCopyAttName(myrelid, colDef->colname);
2958                 if (HeapTupleIsValid(tuple))
2959                 {
2960                         Form_pg_attribute childatt = (Form_pg_attribute) GETSTRUCT(tuple);
2961
2962                         /* Okay if child matches by type */
2963                         if (typenameTypeId(colDef->typename) != childatt->atttypid ||
2964                                 colDef->typename->typmod != childatt->atttypmod)
2965                                 ereport(ERROR,
2966                                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
2967                                                  errmsg("child table \"%s\" has different type for column \"%s\"",
2968                                                         RelationGetRelationName(rel), colDef->colname)));
2969
2970                         /* Bump the existing child att's inhcount */
2971                         childatt->attinhcount++;
2972                         simple_heap_update(attrdesc, &tuple->t_self, tuple);
2973                         CatalogUpdateIndexes(attrdesc, tuple);
2974
2975                         heap_freetuple(tuple);
2976
2977                         /* Inform the user about the merge */
2978                         ereport(NOTICE,
2979                           (errmsg("merging definition of column \"%s\" for child \"%s\"",
2980                                           colDef->colname, RelationGetRelationName(rel))));
2981
2982                         heap_close(attrdesc, RowExclusiveLock);
2983                         return;
2984                 }
2985         }
2986
2987         pgclass = heap_open(RelationRelationId, RowExclusiveLock);
2988
2989         reltup = SearchSysCacheCopy(RELOID,
2990                                                                 ObjectIdGetDatum(myrelid),
2991                                                                 0, 0, 0);
2992         if (!HeapTupleIsValid(reltup))
2993                 elog(ERROR, "cache lookup failed for relation %u", myrelid);
2994
2995         /*
2996          * this test is deliberately not attisdropped-aware, since if one tries to
2997          * add a column matching a dropped column name, it's gonna fail anyway.
2998          */
2999         if (SearchSysCacheExists(ATTNAME,
3000                                                          ObjectIdGetDatum(myrelid),
3001                                                          PointerGetDatum(colDef->colname),
3002                                                          0, 0))
3003                 ereport(ERROR,
3004                                 (errcode(ERRCODE_DUPLICATE_COLUMN),
3005                                  errmsg("column \"%s\" of relation \"%s\" already exists",
3006                                                 colDef->colname, RelationGetRelationName(rel))));
3007
3008         minattnum = ((Form_pg_class) GETSTRUCT(reltup))->relnatts;
3009         maxatts = minattnum + 1;
3010         if (maxatts > MaxHeapAttributeNumber)
3011                 ereport(ERROR,
3012                                 (errcode(ERRCODE_TOO_MANY_COLUMNS),
3013                                  errmsg("tables can have at most %d columns",
3014                                                 MaxHeapAttributeNumber)));
3015         i = minattnum + 1;
3016
3017         typeTuple = typenameType(colDef->typename);
3018         tform = (Form_pg_type) GETSTRUCT(typeTuple);
3019         typeOid = HeapTupleGetOid(typeTuple);
3020
3021         /* make sure datatype is legal for a column */
3022         CheckAttributeType(colDef->colname, typeOid);
3023
3024         attributeTuple = heap_addheader(Natts_pg_attribute,
3025                                                                         false,
3026                                                                         ATTRIBUTE_TUPLE_SIZE,
3027                                                                         (void *) &attributeD);
3028
3029         attribute = (Form_pg_attribute) GETSTRUCT(attributeTuple);
3030
3031         attribute->attrelid = myrelid;
3032         namestrcpy(&(attribute->attname), colDef->colname);
3033         attribute->atttypid = typeOid;
3034         attribute->attstattarget = -1;
3035         attribute->attlen = tform->typlen;
3036         attribute->attcacheoff = -1;
3037         attribute->atttypmod = colDef->typename->typmod;
3038         attribute->attnum = i;
3039         attribute->attbyval = tform->typbyval;
3040         attribute->attndims = list_length(colDef->typename->arrayBounds);
3041         attribute->attstorage = tform->typstorage;
3042         attribute->attalign = tform->typalign;
3043         attribute->attnotnull = colDef->is_not_null;
3044         attribute->atthasdef = false;
3045         attribute->attisdropped = false;
3046         attribute->attislocal = colDef->is_local;
3047         attribute->attinhcount = colDef->inhcount;
3048
3049         ReleaseSysCache(typeTuple);
3050
3051         simple_heap_insert(attrdesc, attributeTuple);
3052
3053         /* Update indexes on pg_attribute */
3054         CatalogUpdateIndexes(attrdesc, attributeTuple);
3055
3056         heap_close(attrdesc, RowExclusiveLock);
3057
3058         /*
3059          * Update number of attributes in pg_class tuple
3060          */
3061         ((Form_pg_class) GETSTRUCT(reltup))->relnatts = maxatts;
3062
3063         simple_heap_update(pgclass, &reltup->t_self, reltup);
3064
3065         /* keep catalog indexes current */
3066         CatalogUpdateIndexes(pgclass, reltup);
3067
3068         heap_freetuple(reltup);
3069
3070         heap_close(pgclass, RowExclusiveLock);
3071
3072         /* Make the attribute's catalog entry visible */
3073         CommandCounterIncrement();
3074
3075         /*
3076          * Store the DEFAULT, if any, in the catalogs
3077          */
3078         if (colDef->raw_default)
3079         {
3080                 RawColumnDefault *rawEnt;
3081
3082                 rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
3083                 rawEnt->attnum = attribute->attnum;
3084                 rawEnt->raw_default = copyObject(colDef->raw_default);
3085
3086                 /*
3087                  * This function is intended for CREATE TABLE, so it processes a
3088                  * _list_ of defaults, but we just do one.
3089                  */
3090                 AddRelationRawConstraints(rel, list_make1(rawEnt), NIL);
3091
3092                 /* Make the additional catalog changes visible */
3093                 CommandCounterIncrement();
3094         }
3095
3096         /*
3097          * Tell Phase 3 to fill in the default expression, if there is one.
3098          *
3099          * If there is no default, Phase 3 doesn't have to do anything, because
3100          * that effectively means that the default is NULL.  The heap tuple access
3101          * routines always check for attnum > # of attributes in tuple, and return
3102          * NULL if so, so without any modification of the tuple data we will get
3103          * the effect of NULL values in the new column.
3104          *
3105          * An exception occurs when the new column is of a domain type: the domain
3106          * might have a NOT NULL constraint, or a check constraint that indirectly
3107          * rejects nulls.  If there are any domain constraints then we construct
3108          * an explicit NULL default value that will be passed through
3109          * CoerceToDomain processing.  (This is a tad inefficient, since it causes
3110          * rewriting the table which we really don't have to do, but the present
3111          * design of domain processing doesn't offer any simple way of checking
3112          * the constraints more directly.)
3113          *
3114          * Note: we use build_column_default, and not just the cooked default
3115          * returned by AddRelationRawConstraints, so that the right thing happens
3116          * when a datatype's default applies.
3117          */
3118         defval = (Expr *) build_column_default(rel, attribute->attnum);
3119
3120         if (!defval && GetDomainConstraints(typeOid) != NIL)
3121         {
3122                 Oid                     basetype = getBaseType(typeOid);
3123
3124                 defval = (Expr *) makeNullConst(basetype);
3125                 defval = (Expr *) coerce_to_target_type(NULL,
3126                                                                                                 (Node *) defval,
3127                                                                                                 basetype,
3128                                                                                                 typeOid,
3129                                                                                                 colDef->typename->typmod,
3130                                                                                                 COERCION_ASSIGNMENT,
3131                                                                                                 COERCE_IMPLICIT_CAST);
3132                 if (defval == NULL)             /* should not happen */
3133                         elog(ERROR, "failed to coerce base type to domain");
3134         }
3135
3136         if (defval)
3137         {
3138                 NewColumnValue *newval;
3139
3140                 newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
3141                 newval->attnum = attribute->attnum;
3142                 newval->expr = defval;
3143
3144                 tab->newvals = lappend(tab->newvals, newval);
3145         }
3146
3147         /*
3148          * Add needed dependency entries for the new column.
3149          */
3150         add_column_datatype_dependency(myrelid, i, attribute->atttypid);
3151         if (colDef->support != NULL)
3152                 add_column_support_dependency(myrelid, i, colDef->support);
3153 }
3154
3155 /*
3156  * Install a column's dependency on its datatype.
3157  */
3158 static void
3159 add_column_datatype_dependency(Oid relid, int32 attnum, Oid typid)
3160 {
3161         ObjectAddress myself,
3162                                 referenced;
3163
3164         myself.classId = RelationRelationId;
3165         myself.objectId = relid;
3166         myself.objectSubId = attnum;
3167         referenced.classId = TypeRelationId;
3168         referenced.objectId = typid;
3169         referenced.objectSubId = 0;
3170         recordDependencyOn(&myself, &referenced, DEPENDENCY_NORMAL);
3171 }
3172
3173 /*
3174  * Install a dependency for a column's supporting relation (serial sequence).
3175  */
3176 static void
3177 add_column_support_dependency(Oid relid, int32 attnum, RangeVar *support)
3178 {
3179         ObjectAddress colobject,
3180                                 suppobject;
3181
3182         colobject.classId = RelationRelationId;
3183         colobject.objectId = relid;
3184         colobject.objectSubId = attnum;
3185         suppobject.classId = RelationRelationId;
3186         suppobject.objectId = RangeVarGetRelid(support, false);
3187         suppobject.objectSubId = 0;
3188         recordDependencyOn(&suppobject, &colobject, DEPENDENCY_INTERNAL);
3189 }
3190
3191 /*
3192  * ALTER TABLE ALTER COLUMN DROP NOT NULL
3193  */
3194 static void
3195 ATExecDropNotNull(Relation rel, const char *colName)
3196 {
3197         HeapTuple       tuple;
3198         AttrNumber      attnum;
3199         Relation        attr_rel;
3200         List       *indexoidlist;
3201         ListCell   *indexoidscan;
3202
3203         /*
3204          * lookup the attribute
3205          */
3206         attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
3207
3208         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3209
3210         if (!HeapTupleIsValid(tuple))
3211                 ereport(ERROR,
3212                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3213                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3214                                                 colName, RelationGetRelationName(rel))));
3215
3216         attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
3217
3218         /* Prevent them from altering a system attribute */
3219         if (attnum <= 0)
3220                 ereport(ERROR,
3221                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3222                                  errmsg("cannot alter system column \"%s\"",
3223                                                 colName)));
3224
3225         /*
3226          * Check that the attribute is not in a primary key
3227          */
3228
3229         /* Loop over all indexes on the relation */
3230         indexoidlist = RelationGetIndexList(rel);
3231
3232         foreach(indexoidscan, indexoidlist)
3233         {
3234                 Oid                     indexoid = lfirst_oid(indexoidscan);
3235                 HeapTuple       indexTuple;
3236                 Form_pg_index indexStruct;
3237                 int                     i;
3238
3239                 indexTuple = SearchSysCache(INDEXRELID,
3240                                                                         ObjectIdGetDatum(indexoid),
3241                                                                         0, 0, 0);
3242                 if (!HeapTupleIsValid(indexTuple))
3243                         elog(ERROR, "cache lookup failed for index %u", indexoid);
3244                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
3245
3246                 /* If the index is not a primary key, skip the check */
3247                 if (indexStruct->indisprimary)
3248                 {
3249                         /*
3250                          * Loop over each attribute in the primary key and see if it
3251                          * matches the to-be-altered attribute
3252                          */
3253                         for (i = 0; i < indexStruct->indnatts; i++)
3254                         {
3255                                 if (indexStruct->indkey.values[i] == attnum)
3256                                         ereport(ERROR,
3257                                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3258                                                          errmsg("column \"%s\" is in a primary key",
3259                                                                         colName)));
3260                         }
3261                 }
3262
3263                 ReleaseSysCache(indexTuple);
3264         }
3265
3266         list_free(indexoidlist);
3267
3268         /*
3269          * Okay, actually perform the catalog change ... if needed
3270          */
3271         if (((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
3272         {
3273                 ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = FALSE;
3274
3275                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
3276
3277                 /* keep the system catalog indexes current */
3278                 CatalogUpdateIndexes(attr_rel, tuple);
3279         }
3280
3281         heap_close(attr_rel, RowExclusiveLock);
3282 }
3283
3284 /*
3285  * ALTER TABLE ALTER COLUMN SET NOT NULL
3286  */
3287 static void
3288 ATExecSetNotNull(AlteredTableInfo *tab, Relation rel,
3289                                  const char *colName)
3290 {
3291         HeapTuple       tuple;
3292         AttrNumber      attnum;
3293         Relation        attr_rel;
3294         NewConstraint *newcon;
3295
3296         /*
3297          * lookup the attribute
3298          */
3299         attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
3300
3301         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3302
3303         if (!HeapTupleIsValid(tuple))
3304                 ereport(ERROR,
3305                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3306                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3307                                                 colName, RelationGetRelationName(rel))));
3308
3309         attnum = ((Form_pg_attribute) GETSTRUCT(tuple))->attnum;
3310
3311         /* Prevent them from altering a system attribute */
3312         if (attnum <= 0)
3313                 ereport(ERROR,
3314                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3315                                  errmsg("cannot alter system column \"%s\"",
3316                                                 colName)));
3317
3318         /*
3319          * Okay, actually perform the catalog change ... if needed
3320          */
3321         if (!((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull)
3322         {
3323                 ((Form_pg_attribute) GETSTRUCT(tuple))->attnotnull = TRUE;
3324
3325                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
3326
3327                 /* keep the system catalog indexes current */
3328                 CatalogUpdateIndexes(attr_rel, tuple);
3329
3330                 /* Tell Phase 3 to test the constraint */
3331                 newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
3332                 newcon->contype = CONSTR_NOTNULL;
3333                 newcon->attnum = attnum;
3334                 newcon->name = "NOT NULL";
3335
3336                 tab->constraints = lappend(tab->constraints, newcon);
3337         }
3338
3339         heap_close(attr_rel, RowExclusiveLock);
3340 }
3341
3342 /*
3343  * ALTER TABLE ALTER COLUMN SET/DROP DEFAULT
3344  */
3345 static void
3346 ATExecColumnDefault(Relation rel, const char *colName,
3347                                         Node *newDefault)
3348 {
3349         AttrNumber      attnum;
3350
3351         /*
3352          * get the number of the attribute
3353          */
3354         attnum = get_attnum(RelationGetRelid(rel), colName);
3355         if (attnum == InvalidAttrNumber)
3356                 ereport(ERROR,
3357                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3358                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3359                                                 colName, RelationGetRelationName(rel))));
3360
3361         /* Prevent them from altering a system attribute */
3362         if (attnum <= 0)
3363                 ereport(ERROR,
3364                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3365                                  errmsg("cannot alter system column \"%s\"",
3366                                                 colName)));
3367
3368         /*
3369          * Remove any old default for the column.  We use RESTRICT here for
3370          * safety, but at present we do not expect anything to depend on the
3371          * default.
3372          */
3373         RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, false);
3374
3375         if (newDefault)
3376         {
3377                 /* SET DEFAULT */
3378                 RawColumnDefault *rawEnt;
3379
3380                 rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
3381                 rawEnt->attnum = attnum;
3382                 rawEnt->raw_default = newDefault;
3383
3384                 /*
3385                  * This function is intended for CREATE TABLE, so it processes a
3386                  * _list_ of defaults, but we just do one.
3387                  */
3388                 AddRelationRawConstraints(rel, list_make1(rawEnt), NIL);
3389         }
3390 }
3391
3392 /*
3393  * ALTER TABLE ALTER COLUMN SET STATISTICS
3394  */
3395 static void
3396 ATPrepSetStatistics(Relation rel, const char *colName, Node *flagValue)
3397 {
3398         /*
3399          * We do our own permission checking because (a) we want to allow SET
3400          * STATISTICS on indexes (for expressional index columns), and (b) we want
3401          * to allow SET STATISTICS on system catalogs without requiring
3402          * allowSystemTableMods to be turned on.
3403          */
3404         if (rel->rd_rel->relkind != RELKIND_RELATION &&
3405                 rel->rd_rel->relkind != RELKIND_INDEX)
3406                 ereport(ERROR,
3407                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3408                                  errmsg("\"%s\" is not a table or index",
3409                                                 RelationGetRelationName(rel))));
3410
3411         /* Permissions checks */
3412         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
3413                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
3414                                            RelationGetRelationName(rel));
3415 }
3416
3417 static void
3418 ATExecSetStatistics(Relation rel, const char *colName, Node *newValue)
3419 {
3420         int                     newtarget;
3421         Relation        attrelation;
3422         HeapTuple       tuple;
3423         Form_pg_attribute attrtuple;
3424
3425         Assert(IsA(newValue, Integer));
3426         newtarget = intVal(newValue);
3427
3428         /*
3429          * Limit target to a sane range
3430          */
3431         if (newtarget < -1)
3432         {
3433                 ereport(ERROR,
3434                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3435                                  errmsg("statistics target %d is too low",
3436                                                 newtarget)));
3437         }
3438         else if (newtarget > 1000)
3439         {
3440                 newtarget = 1000;
3441                 ereport(WARNING,
3442                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3443                                  errmsg("lowering statistics target to %d",
3444                                                 newtarget)));
3445         }
3446
3447         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
3448
3449         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3450
3451         if (!HeapTupleIsValid(tuple))
3452                 ereport(ERROR,
3453                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3454                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3455                                                 colName, RelationGetRelationName(rel))));
3456         attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
3457
3458         if (attrtuple->attnum <= 0)
3459                 ereport(ERROR,
3460                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3461                                  errmsg("cannot alter system column \"%s\"",
3462                                                 colName)));
3463
3464         attrtuple->attstattarget = newtarget;
3465
3466         simple_heap_update(attrelation, &tuple->t_self, tuple);
3467
3468         /* keep system catalog indexes current */
3469         CatalogUpdateIndexes(attrelation, tuple);
3470
3471         heap_freetuple(tuple);
3472
3473         heap_close(attrelation, RowExclusiveLock);
3474 }
3475
3476 /*
3477  * ALTER TABLE ALTER COLUMN SET STORAGE
3478  */
3479 static void
3480 ATExecSetStorage(Relation rel, const char *colName, Node *newValue)
3481 {
3482         char       *storagemode;
3483         char            newstorage;
3484         Relation        attrelation;
3485         HeapTuple       tuple;
3486         Form_pg_attribute attrtuple;
3487
3488         Assert(IsA(newValue, String));
3489         storagemode = strVal(newValue);
3490
3491         if (pg_strcasecmp(storagemode, "plain") == 0)
3492                 newstorage = 'p';
3493         else if (pg_strcasecmp(storagemode, "external") == 0)
3494                 newstorage = 'e';
3495         else if (pg_strcasecmp(storagemode, "extended") == 0)
3496                 newstorage = 'x';
3497         else if (pg_strcasecmp(storagemode, "main") == 0)
3498                 newstorage = 'm';
3499         else
3500         {
3501                 ereport(ERROR,
3502                                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
3503                                  errmsg("invalid storage type \"%s\"",
3504                                                 storagemode)));
3505                 newstorage = 0;                 /* keep compiler quiet */
3506         }
3507
3508         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
3509
3510         tuple = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
3511
3512         if (!HeapTupleIsValid(tuple))
3513                 ereport(ERROR,
3514                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3515                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3516                                                 colName, RelationGetRelationName(rel))));
3517         attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
3518
3519         if (attrtuple->attnum <= 0)
3520                 ereport(ERROR,
3521                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3522                                  errmsg("cannot alter system column \"%s\"",
3523                                                 colName)));
3524
3525         /*
3526          * safety check: do not allow toasted storage modes unless column datatype
3527          * is TOAST-aware.
3528          */
3529         if (newstorage == 'p' || TypeIsToastable(attrtuple->atttypid))
3530                 attrtuple->attstorage = newstorage;
3531         else
3532                 ereport(ERROR,
3533                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3534                                  errmsg("column data type %s can only have storage PLAIN",
3535                                                 format_type_be(attrtuple->atttypid))));
3536
3537         simple_heap_update(attrelation, &tuple->t_self, tuple);
3538
3539         /* keep system catalog indexes current */
3540         CatalogUpdateIndexes(attrelation, tuple);
3541
3542         heap_freetuple(tuple);
3543
3544         heap_close(attrelation, RowExclusiveLock);
3545 }
3546
3547
3548 /*
3549  * ALTER TABLE DROP COLUMN
3550  *
3551  * DROP COLUMN cannot use the normal ALTER TABLE recursion mechanism,
3552  * because we have to decide at runtime whether to recurse or not depending
3553  * on whether attinhcount goes to zero or not.  (We can't check this in a
3554  * static pre-pass because it won't handle multiple inheritance situations
3555  * correctly.)  Since DROP COLUMN doesn't need to create any work queue
3556  * entries for Phase 3, it's okay to recurse internally in this routine
3557  * without considering the work queue.
3558  */
3559 static void
3560 ATExecDropColumn(Relation rel, const char *colName,
3561                                  DropBehavior behavior,
3562                                  bool recurse, bool recursing)
3563 {
3564         HeapTuple       tuple;
3565         Form_pg_attribute targetatt;
3566         AttrNumber      attnum;
3567         List       *children;
3568         ObjectAddress object;
3569
3570         /* At top level, permission check was done in ATPrepCmd, else do it */
3571         if (recursing)
3572                 ATSimplePermissions(rel, false);
3573
3574         /*
3575          * get the number of the attribute
3576          */
3577         tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
3578         if (!HeapTupleIsValid(tuple))
3579                 ereport(ERROR,
3580                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
3581                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
3582                                                 colName, RelationGetRelationName(rel))));
3583         targetatt = (Form_pg_attribute) GETSTRUCT(tuple);
3584
3585         attnum = targetatt->attnum;
3586
3587         /* Can't drop a system attribute, except OID */
3588         if (attnum <= 0 && attnum != ObjectIdAttributeNumber)
3589                 ereport(ERROR,
3590                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3591                                  errmsg("cannot drop system column \"%s\"",
3592                                                 colName)));
3593
3594         /* Don't drop inherited columns */
3595         if (targetatt->attinhcount > 0 && !recursing)
3596                 ereport(ERROR,
3597                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3598                                  errmsg("cannot drop inherited column \"%s\"",
3599                                                 colName)));
3600
3601         ReleaseSysCache(tuple);
3602
3603         /*
3604          * Propagate to children as appropriate.  Unlike most other ALTER
3605          * routines, we have to do this one level of recursion at a time; we can't
3606          * use find_all_inheritors to do it in one pass.
3607          */
3608         children = find_inheritance_children(RelationGetRelid(rel));
3609
3610         if (children)
3611         {
3612                 Relation        attr_rel;
3613                 ListCell   *child;
3614
3615                 attr_rel = heap_open(AttributeRelationId, RowExclusiveLock);
3616                 foreach(child, children)
3617                 {
3618                         Oid                     childrelid = lfirst_oid(child);
3619                         Relation        childrel;
3620                         Form_pg_attribute childatt;
3621
3622                         childrel = heap_open(childrelid, AccessExclusiveLock);
3623
3624                         tuple = SearchSysCacheCopyAttName(childrelid, colName);
3625                         if (!HeapTupleIsValid(tuple))           /* shouldn't happen */
3626                                 elog(ERROR, "cache lookup failed for attribute \"%s\" of relation %u",
3627                                          colName, childrelid);
3628                         childatt = (Form_pg_attribute) GETSTRUCT(tuple);
3629
3630                         if (childatt->attinhcount <= 0)         /* shouldn't happen */
3631                                 elog(ERROR, "relation %u has non-inherited attribute \"%s\"",
3632                                          childrelid, colName);
3633
3634                         if (recurse)
3635                         {
3636                                 /*
3637                                  * If the child column has other definition sources, just
3638                                  * decrement its inheritance count; if not, recurse to delete
3639                                  * it.
3640                                  */
3641                                 if (childatt->attinhcount == 1 && !childatt->attislocal)
3642                                 {
3643                                         /* Time to delete this child column, too */
3644                                         ATExecDropColumn(childrel, colName, behavior, true, true);
3645                                 }
3646                                 else
3647                                 {
3648                                         /* Child column must survive my deletion */
3649                                         childatt->attinhcount--;
3650
3651                                         simple_heap_update(attr_rel, &tuple->t_self, tuple);
3652
3653                                         /* keep the system catalog indexes current */
3654                                         CatalogUpdateIndexes(attr_rel, tuple);
3655
3656                                         /* Make update visible */
3657                                         CommandCounterIncrement();
3658                                 }
3659                         }
3660                         else
3661                         {
3662                                 /*
3663                                  * If we were told to drop ONLY in this table (no recursion),
3664                                  * we need to mark the inheritors' attribute as locally
3665                                  * defined rather than inherited.
3666                                  */
3667                                 childatt->attinhcount--;
3668                                 childatt->attislocal = true;
3669
3670                                 simple_heap_update(attr_rel, &tuple->t_self, tuple);
3671
3672                                 /* keep the system catalog indexes current */
3673                                 CatalogUpdateIndexes(attr_rel, tuple);
3674
3675                                 /* Make update visible */
3676                                 CommandCounterIncrement();
3677                         }
3678
3679                         heap_freetuple(tuple);
3680
3681                         heap_close(childrel, NoLock);
3682                 }
3683                 heap_close(attr_rel, RowExclusiveLock);
3684         }
3685
3686         /*
3687          * Perform the actual column deletion
3688          */
3689         object.classId = RelationRelationId;
3690         object.objectId = RelationGetRelid(rel);
3691         object.objectSubId = attnum;
3692
3693         performDeletion(&object, behavior);
3694
3695         /*
3696          * If we dropped the OID column, must adjust pg_class.relhasoids
3697          */
3698         if (attnum == ObjectIdAttributeNumber)
3699         {
3700                 Relation        class_rel;
3701                 Form_pg_class tuple_class;
3702
3703                 class_rel = heap_open(RelationRelationId, RowExclusiveLock);
3704
3705                 tuple = SearchSysCacheCopy(RELOID,
3706                                                                    ObjectIdGetDatum(RelationGetRelid(rel)),
3707                                                                    0, 0, 0);
3708                 if (!HeapTupleIsValid(tuple))
3709                         elog(ERROR, "cache lookup failed for relation %u",
3710                                  RelationGetRelid(rel));
3711                 tuple_class = (Form_pg_class) GETSTRUCT(tuple);
3712
3713                 tuple_class->relhasoids = false;
3714                 simple_heap_update(class_rel, &tuple->t_self, tuple);
3715
3716                 /* Keep the catalog indexes up to date */
3717                 CatalogUpdateIndexes(class_rel, tuple);
3718
3719                 heap_close(class_rel, RowExclusiveLock);
3720         }
3721 }
3722
3723 /*
3724  * ALTER TABLE ADD INDEX
3725  *
3726  * There is no such command in the grammar, but the parser converts UNIQUE
3727  * and PRIMARY KEY constraints into AT_AddIndex subcommands.  This lets us
3728  * schedule creation of the index at the appropriate time during ALTER.
3729  */
3730 static void
3731 ATExecAddIndex(AlteredTableInfo *tab, Relation rel,
3732                            IndexStmt *stmt, bool is_rebuild)
3733 {
3734         bool            check_rights;
3735         bool            skip_build;
3736         bool            quiet;
3737
3738         Assert(IsA(stmt, IndexStmt));
3739
3740         /* suppress schema rights check when rebuilding existing index */
3741         check_rights = !is_rebuild;
3742         /* skip index build if phase 3 will have to rewrite table anyway */
3743         skip_build = (tab->newvals != NIL);
3744         /* suppress notices when rebuilding existing index */
3745         quiet = is_rebuild;
3746
3747         DefineIndex(stmt->relation, /* relation */
3748                                 stmt->idxname,  /* index name */
3749                                 InvalidOid,             /* no predefined OID */
3750                                 stmt->accessMethod,             /* am name */
3751                                 stmt->tableSpace,
3752                                 stmt->indexParams,              /* parameters */
3753                                 (Expr *) stmt->whereClause,
3754                                 stmt->rangetable,
3755                                 stmt->unique,
3756                                 stmt->primary,
3757                                 stmt->isconstraint,
3758                                 true,                   /* is_alter_table */
3759                                 check_rights,
3760                                 skip_build,
3761                                 quiet);
3762 }
3763
3764 /*
3765  * ALTER TABLE ADD CONSTRAINT
3766  */
3767 static void
3768 ATExecAddConstraint(AlteredTableInfo *tab, Relation rel, Node *newConstraint)
3769 {
3770         switch (nodeTag(newConstraint))
3771         {
3772                 case T_Constraint:
3773                         {
3774                                 Constraint *constr = (Constraint *) newConstraint;
3775
3776                                 /*
3777                                  * Currently, we only expect to see CONSTR_CHECK nodes
3778                                  * arriving here (see the preprocessing done in
3779                                  * parser/analyze.c).  Use a switch anyway to make it easier
3780                                  * to add more code later.
3781                                  */
3782                                 switch (constr->contype)
3783                                 {
3784                                         case CONSTR_CHECK:
3785                                                 {
3786                                                         List       *newcons;
3787                                                         ListCell   *lcon;
3788
3789                                                         /*
3790                                                          * Call AddRelationRawConstraints to do the work.
3791                                                          * It returns a list of cooked constraints.
3792                                                          */
3793                                                         newcons = AddRelationRawConstraints(rel, NIL,
3794                                                                                                                  list_make1(constr));
3795                                                         /* Add each constraint to Phase 3's queue */
3796                                                         foreach(lcon, newcons)
3797                                                         {
3798                                                                 CookedConstraint *ccon = (CookedConstraint *) lfirst(lcon);
3799                                                                 NewConstraint *newcon;
3800
3801                                                                 newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
3802                                                                 newcon->name = ccon->name;
3803                                                                 newcon->contype = ccon->contype;
3804                                                                 newcon->attnum = ccon->attnum;
3805                                                                 /* ExecQual wants implicit-AND format */
3806                                                                 newcon->qual = (Node *)
3807                                                                         make_ands_implicit((Expr *) ccon->expr);
3808
3809                                                                 tab->constraints = lappend(tab->constraints,
3810                                                                                                                    newcon);
3811                                                         }
3812                                                         break;
3813                                                 }
3814                                         default:
3815                                                 elog(ERROR, "unrecognized constraint type: %d",
3816                                                          (int) constr->contype);
3817                                 }
3818                                 break;
3819                         }
3820                 case T_FkConstraint:
3821                         {
3822                                 FkConstraint *fkconstraint = (FkConstraint *) newConstraint;
3823
3824                                 /*
3825                                  * Assign or validate constraint name
3826                                  */
3827                                 if (fkconstraint->constr_name)
3828                                 {
3829                                         if (ConstraintNameIsUsed(CONSTRAINT_RELATION,
3830                                                                                          RelationGetRelid(rel),
3831                                                                                          RelationGetNamespace(rel),
3832                                                                                          fkconstraint->constr_name))
3833                                                 ereport(ERROR,
3834                                                                 (errcode(ERRCODE_DUPLICATE_OBJECT),
3835                                                                  errmsg("constraint \"%s\" for relation \"%s\" already exists",
3836                                                                                 fkconstraint->constr_name,
3837                                                                                 RelationGetRelationName(rel))));
3838                                 }
3839                                 else
3840                                         fkconstraint->constr_name =
3841                                                 ChooseConstraintName(RelationGetRelationName(rel),
3842                                                                         strVal(linitial(fkconstraint->fk_attrs)),
3843                                                                                          "fkey",
3844                                                                                          RelationGetNamespace(rel),
3845                                                                                          NIL);
3846
3847                                 ATAddForeignKeyConstraint(tab, rel, fkconstraint);
3848
3849                                 break;
3850                         }
3851                 default:
3852                         elog(ERROR, "unrecognized node type: %d",
3853                                  (int) nodeTag(newConstraint));
3854         }
3855 }
3856
3857 /*
3858  * Add a foreign-key constraint to a single table
3859  *
3860  * Subroutine for ATExecAddConstraint.  Must already hold exclusive
3861  * lock on the rel, and have done appropriate validity/permissions checks
3862  * for it.
3863  */
3864 static void
3865 ATAddForeignKeyConstraint(AlteredTableInfo *tab, Relation rel,
3866                                                   FkConstraint *fkconstraint)
3867 {
3868         Relation        pkrel;
3869         AclResult       aclresult;
3870         int16           pkattnum[INDEX_MAX_KEYS];
3871         int16           fkattnum[INDEX_MAX_KEYS];
3872         Oid                     pktypoid[INDEX_MAX_KEYS];
3873         Oid                     fktypoid[INDEX_MAX_KEYS];
3874         Oid                     opclasses[INDEX_MAX_KEYS];
3875         int                     i;
3876         int                     numfks,
3877                                 numpks;
3878         Oid                     indexOid;
3879         Oid                     constrOid;
3880
3881         /*
3882          * Grab an exclusive lock on the pk table, so that someone doesn't delete
3883          * rows out from under us. (Although a lesser lock would do for that
3884          * purpose, we'll need exclusive lock anyway to add triggers to the pk
3885          * table; trying to start with a lesser lock will just create a risk of
3886          * deadlock.)
3887          */
3888         pkrel = heap_openrv(fkconstraint->pktable, AccessExclusiveLock);
3889
3890         /*
3891          * Validity and permissions checks
3892          *
3893          * Note: REFERENCES permissions checks are redundant with CREATE TRIGGER,
3894          * but we may as well error out sooner instead of later.
3895          */
3896         if (pkrel->rd_rel->relkind != RELKIND_RELATION)
3897                 ereport(ERROR,
3898                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
3899                                  errmsg("referenced relation \"%s\" is not a table",
3900                                                 RelationGetRelationName(pkrel))));
3901
3902         aclresult = pg_class_aclcheck(RelationGetRelid(pkrel), GetUserId(),
3903                                                                   ACL_REFERENCES);
3904         if (aclresult != ACLCHECK_OK)
3905                 aclcheck_error(aclresult, ACL_KIND_CLASS,
3906                                            RelationGetRelationName(pkrel));
3907
3908         if (!allowSystemTableMods && IsSystemRelation(pkrel))
3909                 ereport(ERROR,
3910                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
3911                                  errmsg("permission denied: \"%s\" is a system catalog",
3912                                                 RelationGetRelationName(pkrel))));
3913
3914         aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
3915                                                                   ACL_REFERENCES);
3916         if (aclresult != ACLCHECK_OK)
3917                 aclcheck_error(aclresult, ACL_KIND_CLASS,
3918                                            RelationGetRelationName(rel));
3919
3920         /*
3921          * Disallow reference from permanent table to temp table or vice versa.
3922          * (The ban on perm->temp is for fairly obvious reasons.  The ban on
3923          * temp->perm is because other backends might need to run the RI triggers
3924          * on the perm table, but they can't reliably see tuples the owning
3925          * backend has created in the temp table, because non-shared buffers are
3926          * used for temp tables.)
3927          */
3928         if (isTempNamespace(RelationGetNamespace(pkrel)))
3929         {
3930                 if (!isTempNamespace(RelationGetNamespace(rel)))
3931                         ereport(ERROR,
3932                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3933                                          errmsg("cannot reference temporary table from permanent table constraint")));
3934         }
3935         else
3936         {
3937                 if (isTempNamespace(RelationGetNamespace(rel)))
3938                         ereport(ERROR,
3939                                         (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
3940                                          errmsg("cannot reference permanent table from temporary table constraint")));
3941         }
3942
3943         /*
3944          * Look up the referencing attributes to make sure they exist, and record
3945          * their attnums and type OIDs.
3946          */
3947         MemSet(pkattnum, 0, sizeof(pkattnum));
3948         MemSet(fkattnum, 0, sizeof(fkattnum));
3949         MemSet(pktypoid, 0, sizeof(pktypoid));
3950         MemSet(fktypoid, 0, sizeof(fktypoid));
3951         MemSet(opclasses, 0, sizeof(opclasses));
3952
3953         numfks = transformColumnNameList(RelationGetRelid(rel),
3954                                                                          fkconstraint->fk_attrs,
3955                                                                          fkattnum, fktypoid);
3956
3957         /*
3958          * If the attribute list for the referenced table was omitted, lookup the
3959          * definition of the primary key and use it.  Otherwise, validate the
3960          * supplied attribute list.  In either case, discover the index OID and
3961          * index opclasses, and the attnums and type OIDs of the attributes.
3962          */
3963         if (fkconstraint->pk_attrs == NIL)
3964         {
3965                 numpks = transformFkeyGetPrimaryKey(pkrel, &indexOid,
3966                                                                                         &fkconstraint->pk_attrs,
3967                                                                                         pkattnum, pktypoid,
3968                                                                                         opclasses);
3969         }
3970         else
3971         {
3972                 numpks = transformColumnNameList(RelationGetRelid(pkrel),
3973                                                                                  fkconstraint->pk_attrs,
3974                                                                                  pkattnum, pktypoid);
3975                 /* Look for an index matching the column list */
3976                 indexOid = transformFkeyCheckAttrs(pkrel, numpks, pkattnum,
3977                                                                                    opclasses);
3978         }
3979
3980         /* Be sure referencing and referenced column types are comparable */
3981         if (numfks != numpks)
3982                 ereport(ERROR,
3983                                 (errcode(ERRCODE_INVALID_FOREIGN_KEY),
3984                                  errmsg("number of referencing and referenced columns for foreign key disagree")));
3985
3986         for (i = 0; i < numpks; i++)
3987         {
3988                 /*
3989                  * pktypoid[i] is the primary key table's i'th key's type fktypoid[i]
3990                  * is the foreign key table's i'th key's type
3991                  *
3992                  * Note that we look for an operator with the PK type on the left;
3993                  * when the types are different this is critical because the PK index
3994                  * will need operators with the indexkey on the left. (Ordinarily both
3995                  * commutator operators will exist if either does, but we won't get
3996                  * the right answer from the test below on opclass membership unless
3997                  * we select the proper operator.)
3998                  */
3999                 Operator        o = oper(list_make1(makeString("=")),
4000                                                          pktypoid[i], fktypoid[i], true);
4001
4002                 if (o == NULL)
4003                         ereport(ERROR,
4004                                         (errcode(ERRCODE_UNDEFINED_FUNCTION),
4005                                          errmsg("foreign key constraint \"%s\" "
4006                                                         "cannot be implemented",
4007                                                         fkconstraint->constr_name),
4008                                          errdetail("Key columns \"%s\" and \"%s\" "
4009                                                            "are of incompatible types: %s and %s.",
4010                                                            strVal(list_nth(fkconstraint->fk_attrs, i)),
4011                                                            strVal(list_nth(fkconstraint->pk_attrs, i)),
4012                                                            format_type_be(fktypoid[i]),
4013                                                            format_type_be(pktypoid[i]))));
4014
4015                 /*
4016                  * Check that the found operator is compatible with the PK index, and
4017                  * generate a warning if not, since otherwise costly seqscans will be
4018                  * incurred to check FK validity.
4019                  */
4020                 if (!op_in_opclass(oprid(o), opclasses[i]))
4021                         ereport(WARNING,
4022                                         (errmsg("foreign key constraint \"%s\" "
4023                                                         "will require costly sequential scans",
4024                                                         fkconstraint->constr_name),
4025                                          errdetail("Key columns \"%s\" and \"%s\" "
4026                                                            "are of different types: %s and %s.",
4027                                                            strVal(list_nth(fkconstraint->fk_attrs, i)),
4028                                                            strVal(list_nth(fkconstraint->pk_attrs, i)),
4029                                                            format_type_be(fktypoid[i]),
4030                                                            format_type_be(pktypoid[i]))));
4031
4032                 ReleaseSysCache(o);
4033         }
4034
4035         /*
4036          * Tell Phase 3 to check that the constraint is satisfied by existing rows
4037          * (we can skip this during table creation).
4038          */
4039         if (!fkconstraint->skip_validation)
4040         {
4041                 NewConstraint *newcon;
4042
4043                 newcon = (NewConstraint *) palloc0(sizeof(NewConstraint));
4044                 newcon->name = fkconstraint->constr_name;
4045                 newcon->contype = CONSTR_FOREIGN;
4046                 newcon->refrelid = RelationGetRelid(pkrel);
4047                 newcon->qual = (Node *) fkconstraint;
4048
4049                 tab->constraints = lappend(tab->constraints, newcon);
4050         }
4051
4052         /*
4053          * Record the FK constraint in pg_constraint.
4054          */
4055         constrOid = CreateConstraintEntry(fkconstraint->constr_name,
4056                                                                           RelationGetNamespace(rel),
4057                                                                           CONSTRAINT_FOREIGN,
4058                                                                           fkconstraint->deferrable,
4059                                                                           fkconstraint->initdeferred,
4060                                                                           RelationGetRelid(rel),
4061                                                                           fkattnum,
4062                                                                           numfks,
4063                                                                           InvalidOid,           /* not a domain
4064                                                                                                                  * constraint */
4065                                                                           RelationGetRelid(pkrel),
4066                                                                           pkattnum,
4067                                                                           numpks,
4068                                                                           fkconstraint->fk_upd_action,
4069                                                                           fkconstraint->fk_del_action,
4070                                                                           fkconstraint->fk_matchtype,
4071                                                                           indexOid,
4072                                                                           NULL,         /* no check constraint */
4073                                                                           NULL,
4074                                                                           NULL);
4075
4076         /*
4077          * Create the triggers that will enforce the constraint.
4078          */
4079         createForeignKeyTriggers(rel, fkconstraint, constrOid);
4080
4081         /*
4082          * Close pk table, but keep lock until we've committed.
4083          */
4084         heap_close(pkrel, NoLock);
4085 }
4086
4087
4088 /*
4089  * transformColumnNameList - transform list of column names
4090  *
4091  * Lookup each name and return its attnum and type OID
4092  */
4093 static int
4094 transformColumnNameList(Oid relId, List *colList,
4095                                                 int16 *attnums, Oid *atttypids)
4096 {
4097         ListCell   *l;
4098         int                     attnum;
4099
4100         attnum = 0;
4101         foreach(l, colList)
4102         {
4103                 char       *attname = strVal(lfirst(l));
4104                 HeapTuple       atttuple;
4105
4106                 atttuple = SearchSysCacheAttName(relId, attname);
4107                 if (!HeapTupleIsValid(atttuple))
4108                         ereport(ERROR,
4109                                         (errcode(ERRCODE_UNDEFINED_COLUMN),
4110                                          errmsg("column \"%s\" referenced in foreign key constraint does not exist",
4111                                                         attname)));
4112                 if (attnum >= INDEX_MAX_KEYS)
4113                         ereport(ERROR,
4114                                         (errcode(ERRCODE_TOO_MANY_COLUMNS),
4115                                          errmsg("cannot have more than %d keys in a foreign key",
4116                                                         INDEX_MAX_KEYS)));
4117                 attnums[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->attnum;
4118                 atttypids[attnum] = ((Form_pg_attribute) GETSTRUCT(atttuple))->atttypid;
4119                 ReleaseSysCache(atttuple);
4120                 attnum++;
4121         }
4122
4123         return attnum;
4124 }
4125
4126 /*
4127  * transformFkeyGetPrimaryKey -
4128  *
4129  *      Look up the names, attnums, and types of the primary key attributes
4130  *      for the pkrel.  Also return the index OID and index opclasses of the
4131  *      index supporting the primary key.
4132  *
4133  *      All parameters except pkrel are output parameters.      Also, the function
4134  *      return value is the number of attributes in the primary key.
4135  *
4136  *      Used when the column list in the REFERENCES specification is omitted.
4137  */
4138 static int
4139 transformFkeyGetPrimaryKey(Relation pkrel, Oid *indexOid,
4140                                                    List **attnamelist,
4141                                                    int16 *attnums, Oid *atttypids,
4142                                                    Oid *opclasses)
4143 {
4144         List       *indexoidlist;
4145         ListCell   *indexoidscan;
4146         HeapTuple       indexTuple = NULL;
4147         Form_pg_index indexStruct = NULL;
4148         Datum           indclassDatum;
4149         bool            isnull;
4150         oidvector  *indclass;
4151         int                     i;
4152
4153         /*
4154          * Get the list of index OIDs for the table from the relcache, and look up
4155          * each one in the pg_index syscache until we find one marked primary key
4156          * (hopefully there isn't more than one such).
4157          */
4158         *indexOid = InvalidOid;
4159
4160         indexoidlist = RelationGetIndexList(pkrel);
4161
4162         foreach(indexoidscan, indexoidlist)
4163         {
4164                 Oid                     indexoid = lfirst_oid(indexoidscan);
4165
4166                 indexTuple = SearchSysCache(INDEXRELID,
4167                                                                         ObjectIdGetDatum(indexoid),
4168                                                                         0, 0, 0);
4169                 if (!HeapTupleIsValid(indexTuple))
4170                         elog(ERROR, "cache lookup failed for index %u", indexoid);
4171                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
4172                 if (indexStruct->indisprimary)
4173                 {
4174                         *indexOid = indexoid;
4175                         break;
4176                 }
4177                 ReleaseSysCache(indexTuple);
4178         }
4179
4180         list_free(indexoidlist);
4181
4182         /*
4183          * Check that we found it
4184          */
4185         if (!OidIsValid(*indexOid))
4186                 ereport(ERROR,
4187                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
4188                                  errmsg("there is no primary key for referenced table \"%s\"",
4189                                                 RelationGetRelationName(pkrel))));
4190
4191         /* Must get indclass the hard way */
4192         indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
4193                                                                         Anum_pg_index_indclass, &isnull);
4194         Assert(!isnull);
4195         indclass = (oidvector *) DatumGetPointer(indclassDatum);
4196
4197         /*
4198          * Now build the list of PK attributes from the indkey definition (we
4199          * assume a primary key cannot have expressional elements)
4200          */
4201         *attnamelist = NIL;
4202         for (i = 0; i < indexStruct->indnatts; i++)
4203         {
4204                 int                     pkattno = indexStruct->indkey.values[i];
4205
4206                 attnums[i] = pkattno;
4207                 atttypids[i] = attnumTypeId(pkrel, pkattno);
4208                 opclasses[i] = indclass->values[i];
4209                 *attnamelist = lappend(*attnamelist,
4210                            makeString(pstrdup(NameStr(*attnumAttName(pkrel, pkattno)))));
4211         }
4212
4213         ReleaseSysCache(indexTuple);
4214
4215         return i;
4216 }
4217
4218 /*
4219  * transformFkeyCheckAttrs -
4220  *
4221  *      Make sure that the attributes of a referenced table belong to a unique
4222  *      (or primary key) constraint.  Return the OID of the index supporting
4223  *      the constraint, as well as the opclasses associated with the index
4224  *      columns.
4225  */
4226 static Oid
4227 transformFkeyCheckAttrs(Relation pkrel,
4228                                                 int numattrs, int16 *attnums,
4229                                                 Oid *opclasses) /* output parameter */
4230 {
4231         Oid                     indexoid = InvalidOid;
4232         bool            found = false;
4233         List       *indexoidlist;
4234         ListCell   *indexoidscan;
4235
4236         /*
4237          * Get the list of index OIDs for the table from the relcache, and look up
4238          * each one in the pg_index syscache, and match unique indexes to the list
4239          * of attnums we are given.
4240          */
4241         indexoidlist = RelationGetIndexList(pkrel);
4242
4243         foreach(indexoidscan, indexoidlist)
4244         {
4245                 HeapTuple       indexTuple;
4246                 Form_pg_index indexStruct;
4247                 int                     i,
4248                                         j;
4249
4250                 indexoid = lfirst_oid(indexoidscan);
4251                 indexTuple = SearchSysCache(INDEXRELID,
4252                                                                         ObjectIdGetDatum(indexoid),
4253                                                                         0, 0, 0);
4254                 if (!HeapTupleIsValid(indexTuple))
4255                         elog(ERROR, "cache lookup failed for index %u", indexoid);
4256                 indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
4257
4258                 /*
4259                  * Must have the right number of columns; must be unique and not a
4260                  * partial index; forget it if there are any expressions, too
4261                  */
4262                 if (indexStruct->indnatts == numattrs &&
4263                         indexStruct->indisunique &&
4264                         heap_attisnull(indexTuple, Anum_pg_index_indpred) &&
4265                         heap_attisnull(indexTuple, Anum_pg_index_indexprs))
4266                 {
4267                         /* Must get indclass the hard way */
4268                         Datum           indclassDatum;
4269                         bool            isnull;
4270                         oidvector  *indclass;
4271
4272                         indclassDatum = SysCacheGetAttr(INDEXRELID, indexTuple,
4273                                                                                         Anum_pg_index_indclass, &isnull);
4274                         Assert(!isnull);
4275                         indclass = (oidvector *) DatumGetPointer(indclassDatum);
4276
4277                         /*
4278                          * The given attnum list may match the index columns in any order.
4279                          * Check that each list is a subset of the other.
4280                          */
4281                         for (i = 0; i < numattrs; i++)
4282                         {
4283                                 found = false;
4284                                 for (j = 0; j < numattrs; j++)
4285                                 {
4286                                         if (attnums[i] == indexStruct->indkey.values[j])
4287                                         {
4288                                                 found = true;
4289                                                 break;
4290                                         }
4291                                 }
4292                                 if (!found)
4293                                         break;
4294                         }
4295                         if (found)
4296                         {
4297                                 for (i = 0; i < numattrs; i++)
4298                                 {
4299                                         found = false;
4300                                         for (j = 0; j < numattrs; j++)
4301                                         {
4302                                                 if (attnums[j] == indexStruct->indkey.values[i])
4303                                                 {
4304                                                         opclasses[j] = indclass->values[i];
4305                                                         found = true;
4306                                                         break;
4307                                                 }
4308                                         }
4309                                         if (!found)
4310                                                 break;
4311                                 }
4312                         }
4313                 }
4314                 ReleaseSysCache(indexTuple);
4315                 if (found)
4316                         break;
4317         }
4318
4319         if (!found)
4320                 ereport(ERROR,
4321                                 (errcode(ERRCODE_INVALID_FOREIGN_KEY),
4322                                  errmsg("there is no unique constraint matching given keys for referenced table \"%s\"",
4323                                                 RelationGetRelationName(pkrel))));
4324
4325         list_free(indexoidlist);
4326
4327         return indexoid;
4328 }
4329
4330 /*
4331  * Scan the existing rows in a table to verify they meet a proposed FK
4332  * constraint.
4333  *
4334  * Caller must have opened and locked both relations.
4335  */
4336 static void
4337 validateForeignKeyConstraint(FkConstraint *fkconstraint,
4338                                                          Relation rel,
4339                                                          Relation pkrel)
4340 {
4341         HeapScanDesc scan;
4342         HeapTuple       tuple;
4343         Trigger         trig;
4344         ListCell   *list;
4345         int                     count;
4346
4347         /*
4348          * See if we can do it with a single LEFT JOIN query.  A FALSE result
4349          * indicates we must proceed with the fire-the-trigger method.
4350          */
4351         if (RI_Initial_Check(fkconstraint, rel, pkrel))
4352                 return;
4353
4354         /*
4355          * Scan through each tuple, calling RI_FKey_check_ins (insert trigger) as
4356          * if that tuple had just been inserted.  If any of those fail, it should
4357          * ereport(ERROR) and that's that.
4358          */
4359         MemSet(&trig, 0, sizeof(trig));
4360         trig.tgoid = InvalidOid;
4361         trig.tgname = fkconstraint->constr_name;
4362         trig.tgenabled = TRUE;
4363         trig.tgisconstraint = TRUE;
4364         trig.tgconstrrelid = RelationGetRelid(pkrel);
4365         trig.tgdeferrable = FALSE;
4366         trig.tginitdeferred = FALSE;
4367
4368         trig.tgargs = (char **) palloc(sizeof(char *) *
4369                                                                    (4 + list_length(fkconstraint->fk_attrs)
4370                                                                         + list_length(fkconstraint->pk_attrs)));
4371
4372         trig.tgargs[0] = trig.tgname;
4373         trig.tgargs[1] = RelationGetRelationName(rel);
4374         trig.tgargs[2] = RelationGetRelationName(pkrel);
4375         trig.tgargs[3] = fkMatchTypeToString(fkconstraint->fk_matchtype);
4376         count = 4;
4377         foreach(list, fkconstraint->fk_attrs)
4378         {
4379                 char       *fk_at = strVal(lfirst(list));
4380
4381                 trig.tgargs[count] = fk_at;
4382                 count += 2;
4383         }
4384         count = 5;
4385         foreach(list, fkconstraint->pk_attrs)
4386         {
4387                 char       *pk_at = strVal(lfirst(list));
4388
4389                 trig.tgargs[count] = pk_at;
4390                 count += 2;
4391         }
4392         trig.tgnargs = count - 1;
4393
4394         scan = heap_beginscan(rel, SnapshotNow, 0, NULL);
4395
4396         while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
4397         {
4398                 FunctionCallInfoData fcinfo;
4399                 TriggerData trigdata;
4400
4401                 /*
4402                  * Make a call to the trigger function
4403                  *
4404                  * No parameters are passed, but we do set a context
4405                  */
4406                 MemSet(&fcinfo, 0, sizeof(fcinfo));
4407
4408                 /*
4409                  * We assume RI_FKey_check_ins won't look at flinfo...
4410                  */
4411                 trigdata.type = T_TriggerData;
4412                 trigdata.tg_event = TRIGGER_EVENT_INSERT | TRIGGER_EVENT_ROW;
4413                 trigdata.tg_relation = rel;
4414                 trigdata.tg_trigtuple = tuple;
4415                 trigdata.tg_newtuple = NULL;
4416                 trigdata.tg_trigger = &trig;
4417                 trigdata.tg_trigtuplebuf = scan->rs_cbuf;
4418                 trigdata.tg_newtuplebuf = InvalidBuffer;
4419
4420                 fcinfo.context = (Node *) &trigdata;
4421
4422                 RI_FKey_check_ins(&fcinfo);
4423         }
4424
4425         heap_endscan(scan);
4426
4427         pfree(trig.tgargs);
4428 }
4429
4430 static void
4431 CreateFKCheckTrigger(RangeVar *myRel, FkConstraint *fkconstraint,
4432                                          ObjectAddress *constrobj, ObjectAddress *trigobj,
4433                                          bool on_insert)
4434 {
4435         CreateTrigStmt *fk_trigger;
4436         ListCell   *fk_attr;
4437         ListCell   *pk_attr;
4438
4439         fk_trigger = makeNode(CreateTrigStmt);
4440         fk_trigger->trigname = fkconstraint->constr_name;
4441         fk_trigger->relation = myRel;
4442         fk_trigger->before = false;
4443         fk_trigger->row = true;
4444
4445         /* Either ON INSERT or ON UPDATE */
4446         if (on_insert)
4447         {
4448                 fk_trigger->funcname = SystemFuncName("RI_FKey_check_ins");
4449                 fk_trigger->actions[0] = 'i';
4450         }
4451         else
4452         {
4453                 fk_trigger->funcname = SystemFuncName("RI_FKey_check_upd");
4454                 fk_trigger->actions[0] = 'u';
4455         }
4456         fk_trigger->actions[1] = '\0';
4457
4458         fk_trigger->isconstraint = true;
4459         fk_trigger->deferrable = fkconstraint->deferrable;
4460         fk_trigger->initdeferred = fkconstraint->initdeferred;
4461         fk_trigger->constrrel = fkconstraint->pktable;
4462
4463         fk_trigger->args = NIL;
4464         fk_trigger->args = lappend(fk_trigger->args,
4465                                                            makeString(fkconstraint->constr_name));
4466         fk_trigger->args = lappend(fk_trigger->args,
4467                                                            makeString(myRel->relname));
4468         fk_trigger->args = lappend(fk_trigger->args,
4469                                                            makeString(fkconstraint->pktable->relname));
4470         fk_trigger->args = lappend(fk_trigger->args,
4471                                 makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
4472         if (list_length(fkconstraint->fk_attrs) != list_length(fkconstraint->pk_attrs))
4473                 ereport(ERROR,
4474                                 (errcode(ERRCODE_INVALID_FOREIGN_KEY),
4475                                  errmsg("number of referencing and referenced columns for foreign key disagree")));
4476
4477         forboth(fk_attr, fkconstraint->fk_attrs,
4478                         pk_attr, fkconstraint->pk_attrs)
4479         {
4480                 fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr));
4481                 fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr));
4482         }
4483
4484         trigobj->objectId = CreateTrigger(fk_trigger, true);
4485
4486         /* Register dependency from trigger to constraint */
4487         recordDependencyOn(trigobj, constrobj, DEPENDENCY_INTERNAL);
4488
4489         /* Make changes-so-far visible */
4490         CommandCounterIncrement();
4491 }
4492
4493 /*
4494  * Create the triggers that implement an FK constraint.
4495  */
4496 static void
4497 createForeignKeyTriggers(Relation rel, FkConstraint *fkconstraint,
4498                                                  Oid constrOid)
4499 {
4500         RangeVar   *myRel;
4501         CreateTrigStmt *fk_trigger;
4502         ListCell   *fk_attr;
4503         ListCell   *pk_attr;
4504         ObjectAddress trigobj,
4505                                 constrobj;
4506
4507         /*
4508          * Reconstruct a RangeVar for my relation (not passed in, unfortunately).
4509          */
4510         myRel = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)),
4511                                                  pstrdup(RelationGetRelationName(rel)));
4512
4513         /*
4514          * Preset objectAddress fields
4515          */
4516         constrobj.classId = ConstraintRelationId;
4517         constrobj.objectId = constrOid;
4518         constrobj.objectSubId = 0;
4519         trigobj.classId = TriggerRelationId;
4520         trigobj.objectSubId = 0;
4521
4522         /* Make changes-so-far visible */
4523         CommandCounterIncrement();
4524
4525         /*
4526          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the CHECK
4527          * action for both INSERTs and UPDATEs on the referencing table.
4528          */
4529         CreateFKCheckTrigger(myRel, fkconstraint, &constrobj, &trigobj, true);
4530         CreateFKCheckTrigger(myRel, fkconstraint, &constrobj, &trigobj, false);
4531
4532         /*
4533          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
4534          * DELETE action on the referenced table.
4535          */
4536         fk_trigger = makeNode(CreateTrigStmt);
4537         fk_trigger->trigname = fkconstraint->constr_name;
4538         fk_trigger->relation = fkconstraint->pktable;
4539         fk_trigger->before = false;
4540         fk_trigger->row = true;
4541         fk_trigger->actions[0] = 'd';
4542         fk_trigger->actions[1] = '\0';
4543
4544         fk_trigger->isconstraint = true;
4545         fk_trigger->constrrel = myRel;
4546         switch (fkconstraint->fk_del_action)
4547         {
4548                 case FKCONSTR_ACTION_NOACTION:
4549                         fk_trigger->deferrable = fkconstraint->deferrable;
4550                         fk_trigger->initdeferred = fkconstraint->initdeferred;
4551                         fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_del");
4552                         break;
4553                 case FKCONSTR_ACTION_RESTRICT:
4554                         fk_trigger->deferrable = false;
4555                         fk_trigger->initdeferred = false;
4556                         fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_del");
4557                         break;
4558                 case FKCONSTR_ACTION_CASCADE:
4559                         fk_trigger->deferrable = false;
4560                         fk_trigger->initdeferred = false;
4561                         fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_del");
4562                         break;
4563                 case FKCONSTR_ACTION_SETNULL:
4564                         fk_trigger->deferrable = false;
4565                         fk_trigger->initdeferred = false;
4566                         fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_del");
4567                         break;
4568                 case FKCONSTR_ACTION_SETDEFAULT:
4569                         fk_trigger->deferrable = false;
4570                         fk_trigger->initdeferred = false;
4571                         fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_del");
4572                         break;
4573                 default:
4574                         elog(ERROR, "unrecognized FK action type: %d",
4575                                  (int) fkconstraint->fk_del_action);
4576                         break;
4577         }
4578
4579         fk_trigger->args = NIL;
4580         fk_trigger->args = lappend(fk_trigger->args,
4581                                                            makeString(fkconstraint->constr_name));
4582         fk_trigger->args = lappend(fk_trigger->args,
4583                                                            makeString(myRel->relname));
4584         fk_trigger->args = lappend(fk_trigger->args,
4585                                                            makeString(fkconstraint->pktable->relname));
4586         fk_trigger->args = lappend(fk_trigger->args,
4587                                 makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
4588         forboth(fk_attr, fkconstraint->fk_attrs,
4589                         pk_attr, fkconstraint->pk_attrs)
4590         {
4591                 fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr));
4592                 fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr));
4593         }
4594
4595         trigobj.objectId = CreateTrigger(fk_trigger, true);
4596
4597         /* Register dependency from trigger to constraint */
4598         recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL);
4599
4600         /* Make changes-so-far visible */
4601         CommandCounterIncrement();
4602
4603         /*
4604          * Build and execute a CREATE CONSTRAINT TRIGGER statement for the ON
4605          * UPDATE action on the referenced table.
4606          */
4607         fk_trigger = makeNode(CreateTrigStmt);
4608         fk_trigger->trigname = fkconstraint->constr_name;
4609         fk_trigger->relation = fkconstraint->pktable;
4610         fk_trigger->before = false;
4611         fk_trigger->row = true;
4612         fk_trigger->actions[0] = 'u';
4613         fk_trigger->actions[1] = '\0';
4614         fk_trigger->isconstraint = true;
4615         fk_trigger->constrrel = myRel;
4616         switch (fkconstraint->fk_upd_action)
4617         {
4618                 case FKCONSTR_ACTION_NOACTION:
4619                         fk_trigger->deferrable = fkconstraint->deferrable;
4620                         fk_trigger->initdeferred = fkconstraint->initdeferred;
4621                         fk_trigger->funcname = SystemFuncName("RI_FKey_noaction_upd");
4622                         break;
4623                 case FKCONSTR_ACTION_RESTRICT:
4624                         fk_trigger->deferrable = false;
4625                         fk_trigger->initdeferred = false;
4626                         fk_trigger->funcname = SystemFuncName("RI_FKey_restrict_upd");
4627                         break;
4628                 case FKCONSTR_ACTION_CASCADE:
4629                         fk_trigger->deferrable = false;
4630                         fk_trigger->initdeferred = false;
4631                         fk_trigger->funcname = SystemFuncName("RI_FKey_cascade_upd");
4632                         break;
4633                 case FKCONSTR_ACTION_SETNULL:
4634                         fk_trigger->deferrable = false;
4635                         fk_trigger->initdeferred = false;
4636                         fk_trigger->funcname = SystemFuncName("RI_FKey_setnull_upd");
4637                         break;
4638                 case FKCONSTR_ACTION_SETDEFAULT:
4639                         fk_trigger->deferrable = false;
4640                         fk_trigger->initdeferred = false;
4641                         fk_trigger->funcname = SystemFuncName("RI_FKey_setdefault_upd");
4642                         break;
4643                 default:
4644                         elog(ERROR, "unrecognized FK action type: %d",
4645                                  (int) fkconstraint->fk_upd_action);
4646                         break;
4647         }
4648
4649         fk_trigger->args = NIL;
4650         fk_trigger->args = lappend(fk_trigger->args,
4651                                                            makeString(fkconstraint->constr_name));
4652         fk_trigger->args = lappend(fk_trigger->args,
4653                                                            makeString(myRel->relname));
4654         fk_trigger->args = lappend(fk_trigger->args,
4655                                                            makeString(fkconstraint->pktable->relname));
4656         fk_trigger->args = lappend(fk_trigger->args,
4657                                 makeString(fkMatchTypeToString(fkconstraint->fk_matchtype)));
4658         forboth(fk_attr, fkconstraint->fk_attrs,
4659                         pk_attr, fkconstraint->pk_attrs)
4660         {
4661                 fk_trigger->args = lappend(fk_trigger->args, lfirst(fk_attr));
4662                 fk_trigger->args = lappend(fk_trigger->args, lfirst(pk_attr));
4663         }
4664
4665         trigobj.objectId = CreateTrigger(fk_trigger, true);
4666
4667         /* Register dependency from trigger to constraint */
4668         recordDependencyOn(&trigobj, &constrobj, DEPENDENCY_INTERNAL);
4669 }
4670
4671 /*
4672  * fkMatchTypeToString -
4673  *        convert FKCONSTR_MATCH_xxx code to string to use in trigger args
4674  */
4675 static char *
4676 fkMatchTypeToString(char match_type)
4677 {
4678         switch (match_type)
4679         {
4680                 case FKCONSTR_MATCH_FULL:
4681                         return pstrdup("FULL");
4682                 case FKCONSTR_MATCH_PARTIAL:
4683                         return pstrdup("PARTIAL");
4684                 case FKCONSTR_MATCH_UNSPECIFIED:
4685                         return pstrdup("UNSPECIFIED");
4686                 default:
4687                         elog(ERROR, "unrecognized match type: %d",
4688                                  (int) match_type);
4689         }
4690         return NULL;                            /* can't get here */
4691 }
4692
4693 /*
4694  * ALTER TABLE DROP CONSTRAINT
4695  */
4696 static void
4697 ATPrepDropConstraint(List **wqueue, Relation rel,
4698                                          bool recurse, AlterTableCmd *cmd)
4699 {
4700         /*
4701          * We don't want errors or noise from child tables, so we have to pass
4702          * down a modified command.
4703          */
4704         if (recurse)
4705         {
4706                 AlterTableCmd *childCmd = copyObject(cmd);
4707
4708                 childCmd->subtype = AT_DropConstraintQuietly;
4709                 ATSimpleRecursion(wqueue, rel, childCmd, recurse);
4710         }
4711 }
4712
4713 static void
4714 ATExecDropConstraint(Relation rel, const char *constrName,
4715                                          DropBehavior behavior, bool quiet)
4716 {
4717         int                     deleted;
4718
4719         deleted = RemoveRelConstraints(rel, constrName, behavior);
4720
4721         if (!quiet)
4722         {
4723                 /* If zero constraints deleted, complain */
4724                 if (deleted == 0)
4725                         ereport(ERROR,
4726                                         (errcode(ERRCODE_UNDEFINED_OBJECT),
4727                                          errmsg("constraint \"%s\" does not exist",
4728                                                         constrName)));
4729                 /* Otherwise if more than one constraint deleted, notify */
4730                 else if (deleted > 1)
4731                         ereport(NOTICE,
4732                                         (errmsg("multiple constraints named \"%s\" were dropped",
4733                                                         constrName)));
4734         }
4735 }
4736
4737 /*
4738  * ALTER COLUMN TYPE
4739  */
4740 static void
4741 ATPrepAlterColumnType(List **wqueue,
4742                                           AlteredTableInfo *tab, Relation rel,
4743                                           bool recurse, bool recursing,
4744                                           AlterTableCmd *cmd)
4745 {
4746         char       *colName = cmd->name;
4747         TypeName   *typename = (TypeName *) cmd->def;
4748         HeapTuple       tuple;
4749         Form_pg_attribute attTup;
4750         AttrNumber      attnum;
4751         Oid                     targettype;
4752         Node       *transform;
4753         NewColumnValue *newval;
4754         ParseState *pstate = make_parsestate(NULL);
4755
4756         /* lookup the attribute so we can check inheritance status */
4757         tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
4758         if (!HeapTupleIsValid(tuple))
4759                 ereport(ERROR,
4760                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
4761                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
4762                                                 colName, RelationGetRelationName(rel))));
4763         attTup = (Form_pg_attribute) GETSTRUCT(tuple);
4764         attnum = attTup->attnum;
4765
4766         /* Can't alter a system attribute */
4767         if (attnum <= 0)
4768                 ereport(ERROR,
4769                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4770                                  errmsg("cannot alter system column \"%s\"",
4771                                                 colName)));
4772
4773         /* Don't alter inherited columns */
4774         if (attTup->attinhcount > 0 && !recursing)
4775                 ereport(ERROR,
4776                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
4777                                  errmsg("cannot alter inherited column \"%s\"",
4778                                                 colName)));
4779
4780         /* Look up the target type */
4781         targettype = LookupTypeName(typename);
4782         if (!OidIsValid(targettype))
4783                 ereport(ERROR,
4784                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
4785                                  errmsg("type \"%s\" does not exist",
4786                                                 TypeNameToString(typename))));
4787
4788         /* make sure datatype is legal for a column */
4789         CheckAttributeType(colName, targettype);
4790
4791         /*
4792          * Set up an expression to transform the old data value to the new type.
4793          * If a USING option was given, transform and use that expression, else
4794          * just take the old value and try to coerce it.  We do this first so that
4795          * type incompatibility can be detected before we waste effort, and
4796          * because we need the expression to be parsed against the original table
4797          * rowtype.
4798          */
4799         if (cmd->transform)
4800         {
4801                 RangeTblEntry *rte;
4802
4803                 /* Expression must be able to access vars of old table */
4804                 rte = addRangeTableEntryForRelation(pstate,
4805                                                                                         rel,
4806                                                                                         NULL,
4807                                                                                         false,
4808                                                                                         true);
4809                 addRTEtoQuery(pstate, rte, false, true, true);
4810
4811                 transform = transformExpr(pstate, cmd->transform);
4812
4813                 /* It can't return a set */
4814                 if (expression_returns_set(transform))
4815                         ereport(ERROR,
4816                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
4817                                          errmsg("transform expression must not return a set")));
4818
4819                 /* No subplans or aggregates, either... */
4820                 if (pstate->p_hasSubLinks)
4821                         ereport(ERROR,
4822                                         (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4823                                          errmsg("cannot use subquery in transform expression")));
4824                 if (pstate->p_hasAggs)
4825                         ereport(ERROR,
4826                                         (errcode(ERRCODE_GROUPING_ERROR),
4827                         errmsg("cannot use aggregate function in transform expression")));
4828         }
4829         else
4830         {
4831                 transform = (Node *) makeVar(1, attnum,
4832                                                                          attTup->atttypid, attTup->atttypmod,
4833                                                                          0);
4834         }
4835
4836         transform = coerce_to_target_type(pstate,
4837                                                                           transform, exprType(transform),
4838                                                                           targettype, typename->typmod,
4839                                                                           COERCION_ASSIGNMENT,
4840                                                                           COERCE_IMPLICIT_CAST);
4841         if (transform == NULL)
4842                 ereport(ERROR,
4843                                 (errcode(ERRCODE_DATATYPE_MISMATCH),
4844                                  errmsg("column \"%s\" cannot be cast to type \"%s\"",
4845                                                 colName, TypeNameToString(typename))));
4846
4847         /*
4848          * Add a work queue item to make ATRewriteTable update the column
4849          * contents.
4850          */
4851         newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
4852         newval->attnum = attnum;
4853         newval->expr = (Expr *) transform;
4854
4855         tab->newvals = lappend(tab->newvals, newval);
4856
4857         ReleaseSysCache(tuple);
4858
4859         /*
4860          * The recursion case is handled by ATSimpleRecursion.  However, if we are
4861          * told not to recurse, there had better not be any child tables; else the
4862          * alter would put them out of step.
4863          */
4864         if (recurse)
4865                 ATSimpleRecursion(wqueue, rel, cmd, recurse);
4866         else if (!recursing &&
4867                          find_inheritance_children(RelationGetRelid(rel)) != NIL)
4868                 ereport(ERROR,
4869                                 (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
4870                                  errmsg("type of inherited column \"%s\" must be changed in child tables too",
4871                                                 colName)));
4872 }
4873
4874 static void
4875 ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
4876                                           const char *colName, TypeName *typename)
4877 {
4878         HeapTuple       heapTup;
4879         Form_pg_attribute attTup;
4880         AttrNumber      attnum;
4881         HeapTuple       typeTuple;
4882         Form_pg_type tform;
4883         Oid                     targettype;
4884         Node       *defaultexpr;
4885         Relation        attrelation;
4886         Relation        depRel;
4887         ScanKeyData key[3];
4888         SysScanDesc scan;
4889         HeapTuple       depTup;
4890
4891         attrelation = heap_open(AttributeRelationId, RowExclusiveLock);
4892
4893         /* Look up the target column */
4894         heapTup = SearchSysCacheCopyAttName(RelationGetRelid(rel), colName);
4895         if (!HeapTupleIsValid(heapTup))         /* shouldn't happen */
4896                 ereport(ERROR,
4897                                 (errcode(ERRCODE_UNDEFINED_COLUMN),
4898                                  errmsg("column \"%s\" of relation \"%s\" does not exist",
4899                                                 colName, RelationGetRelationName(rel))));
4900         attTup = (Form_pg_attribute) GETSTRUCT(heapTup);
4901         attnum = attTup->attnum;
4902
4903         /* Check for multiple ALTER TYPE on same column --- can't cope */
4904         if (attTup->atttypid != tab->oldDesc->attrs[attnum - 1]->atttypid ||
4905                 attTup->atttypmod != tab->oldDesc->attrs[attnum - 1]->atttypmod)
4906                 ereport(ERROR,
4907                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4908                                  errmsg("cannot alter type of column \"%s\" twice",
4909                                                 colName)));
4910
4911         /* Look up the target type (should not fail, since prep found it) */
4912         typeTuple = typenameType(typename);
4913         tform = (Form_pg_type) GETSTRUCT(typeTuple);
4914         targettype = HeapTupleGetOid(typeTuple);
4915
4916         /*
4917          * If there is a default expression for the column, get it and ensure we
4918          * can coerce it to the new datatype.  (We must do this before changing
4919          * the column type, because build_column_default itself will try to
4920          * coerce, and will not issue the error message we want if it fails.)
4921          *
4922          * We remove any implicit coercion steps at the top level of the old
4923          * default expression; this has been agreed to satisfy the principle of
4924          * least surprise.      (The conversion to the new column type should act like
4925          * it started from what the user sees as the stored expression, and the
4926          * implicit coercions aren't going to be shown.)
4927          */
4928         if (attTup->atthasdef)
4929         {
4930                 defaultexpr = build_column_default(rel, attnum);
4931                 Assert(defaultexpr);
4932                 defaultexpr = strip_implicit_coercions(defaultexpr);
4933                 defaultexpr = coerce_to_target_type(NULL,               /* no UNKNOWN params */
4934                                                                                   defaultexpr, exprType(defaultexpr),
4935                                                                                         targettype, typename->typmod,
4936                                                                                         COERCION_ASSIGNMENT,
4937                                                                                         COERCE_IMPLICIT_CAST);
4938                 if (defaultexpr == NULL)
4939                         ereport(ERROR,
4940                                         (errcode(ERRCODE_DATATYPE_MISMATCH),
4941                         errmsg("default for column \"%s\" cannot be cast to type \"%s\"",
4942                                    colName, TypeNameToString(typename))));
4943         }
4944         else
4945                 defaultexpr = NULL;
4946
4947         /*
4948          * Find everything that depends on the column (constraints, indexes, etc),
4949          * and record enough information to let us recreate the objects.
4950          *
4951          * The actual recreation does not happen here, but only after we have
4952          * performed all the individual ALTER TYPE operations.  We have to save
4953          * the info before executing ALTER TYPE, though, else the deparser will
4954          * get confused.
4955          *
4956          * There could be multiple entries for the same object, so we must check
4957          * to ensure we process each one only once.  Note: we assume that an index
4958          * that implements a constraint will not show a direct dependency on the
4959          * column.
4960          */
4961         depRel = heap_open(DependRelationId, RowExclusiveLock);
4962
4963         ScanKeyInit(&key[0],
4964                                 Anum_pg_depend_refclassid,
4965                                 BTEqualStrategyNumber, F_OIDEQ,
4966                                 ObjectIdGetDatum(RelationRelationId));
4967         ScanKeyInit(&key[1],
4968                                 Anum_pg_depend_refobjid,
4969                                 BTEqualStrategyNumber, F_OIDEQ,
4970                                 ObjectIdGetDatum(RelationGetRelid(rel)));
4971         ScanKeyInit(&key[2],
4972                                 Anum_pg_depend_refobjsubid,
4973                                 BTEqualStrategyNumber, F_INT4EQ,
4974                                 Int32GetDatum((int32) attnum));
4975
4976         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
4977                                                           SnapshotNow, 3, key);
4978
4979         while (HeapTupleIsValid(depTup = systable_getnext(scan)))
4980         {
4981                 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
4982                 ObjectAddress foundObject;
4983
4984                 /* We don't expect any PIN dependencies on columns */
4985                 if (foundDep->deptype == DEPENDENCY_PIN)
4986                         elog(ERROR, "cannot alter type of a pinned column");
4987
4988                 foundObject.classId = foundDep->classid;
4989                 foundObject.objectId = foundDep->objid;
4990                 foundObject.objectSubId = foundDep->objsubid;
4991
4992                 switch (getObjectClass(&foundObject))
4993                 {
4994                         case OCLASS_CLASS:
4995                                 {
4996                                         char            relKind = get_rel_relkind(foundObject.objectId);
4997
4998                                         if (relKind == RELKIND_INDEX)
4999                                         {
5000                                                 Assert(foundObject.objectSubId == 0);
5001                                                 if (!list_member_oid(tab->changedIndexOids, foundObject.objectId))
5002                                                 {
5003                                                         tab->changedIndexOids = lappend_oid(tab->changedIndexOids,
5004                                                                                                            foundObject.objectId);
5005                                                         tab->changedIndexDefs = lappend(tab->changedIndexDefs,
5006                                                            pg_get_indexdef_string(foundObject.objectId));
5007                                                 }
5008                                         }
5009                                         else if (relKind == RELKIND_SEQUENCE)
5010                                         {
5011                                                 /*
5012                                                  * This must be a SERIAL column's sequence.  We need
5013                                                  * not do anything to it.
5014                                                  */
5015                                                 Assert(foundObject.objectSubId == 0);
5016                                         }
5017                                         else
5018                                         {
5019                                                 /* Not expecting any other direct dependencies... */
5020                                                 elog(ERROR, "unexpected object depending on column: %s",
5021                                                          getObjectDescription(&foundObject));
5022                                         }
5023                                         break;
5024                                 }
5025
5026                         case OCLASS_CONSTRAINT:
5027                                 Assert(foundObject.objectSubId == 0);
5028                                 if (!list_member_oid(tab->changedConstraintOids,
5029                                                                          foundObject.objectId))
5030                                 {
5031                                         char *defstring = pg_get_constraintdef_string(foundObject.objectId);
5032
5033                                         /*
5034                                          * Put NORMAL dependencies at the front of the list and
5035                                          * AUTO dependencies at the back.  This makes sure that
5036                                          * foreign-key constraints depending on this column will
5037                                          * be dropped before unique or primary-key constraints of
5038                                          * the column; which we must have because the FK
5039                                          * constraints depend on the indexes belonging to the
5040                                          * unique constraints.
5041                                          */
5042                                         if (foundDep->deptype == DEPENDENCY_NORMAL)
5043                                         {
5044                                                 tab->changedConstraintOids =
5045                                                         lcons_oid(foundObject.objectId,
5046                                                                           tab->changedConstraintOids);
5047                                                 tab->changedConstraintDefs =
5048                                                         lcons(defstring,
5049                                                                   tab->changedConstraintDefs);
5050                                         }
5051                                         else
5052                                         {
5053                                                 tab->changedConstraintOids =
5054                                                         lappend_oid(tab->changedConstraintOids,
5055                                                                                 foundObject.objectId);
5056                                                 tab->changedConstraintDefs =
5057                                                         lappend(tab->changedConstraintDefs,
5058                                                                         defstring);
5059                                         }
5060                                 }
5061                                 break;
5062
5063                         case OCLASS_REWRITE:
5064                                 /* XXX someday see if we can cope with revising views */
5065                                 ereport(ERROR,
5066                                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5067                                                  errmsg("cannot alter type of a column used by a view or rule"),
5068                                                  errdetail("%s depends on column \"%s\"",
5069                                                                    getObjectDescription(&foundObject),
5070                                                                    colName)));
5071                                 break;
5072
5073                         case OCLASS_DEFAULT:
5074
5075                                 /*
5076                                  * Ignore the column's default expression, since we will fix
5077                                  * it below.
5078                                  */
5079                                 Assert(defaultexpr);
5080                                 break;
5081
5082                         case OCLASS_PROC:
5083                         case OCLASS_TYPE:
5084                         case OCLASS_CAST:
5085                         case OCLASS_CONVERSION:
5086                         case OCLASS_LANGUAGE:
5087                         case OCLASS_OPERATOR:
5088                         case OCLASS_OPCLASS:
5089                         case OCLASS_TRIGGER:
5090                         case OCLASS_SCHEMA:
5091
5092                                 /*
5093                                  * We don't expect any of these sorts of objects to depend on
5094                                  * a column.
5095                                  */
5096                                 elog(ERROR, "unexpected object depending on column: %s",
5097                                          getObjectDescription(&foundObject));
5098                                 break;
5099
5100                         default:
5101                                 elog(ERROR, "unrecognized object class: %u",
5102                                          foundObject.classId);
5103                 }
5104         }
5105
5106         systable_endscan(scan);
5107
5108         /*
5109          * Now scan for dependencies of this column on other things.  The only
5110          * thing we should find is the dependency on the column datatype, which we
5111          * want to remove.
5112          */
5113         ScanKeyInit(&key[0],
5114                                 Anum_pg_depend_classid,
5115                                 BTEqualStrategyNumber, F_OIDEQ,
5116                                 ObjectIdGetDatum(RelationRelationId));
5117         ScanKeyInit(&key[1],
5118                                 Anum_pg_depend_objid,
5119                                 BTEqualStrategyNumber, F_OIDEQ,
5120                                 ObjectIdGetDatum(RelationGetRelid(rel)));
5121         ScanKeyInit(&key[2],
5122                                 Anum_pg_depend_objsubid,
5123                                 BTEqualStrategyNumber, F_INT4EQ,
5124                                 Int32GetDatum((int32) attnum));
5125
5126         scan = systable_beginscan(depRel, DependDependerIndexId, true,
5127                                                           SnapshotNow, 3, key);
5128
5129         while (HeapTupleIsValid(depTup = systable_getnext(scan)))
5130         {
5131                 Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(depTup);
5132
5133                 if (foundDep->deptype != DEPENDENCY_NORMAL)
5134                         elog(ERROR, "found unexpected dependency type '%c'",
5135                                  foundDep->deptype);
5136                 if (foundDep->refclassid != TypeRelationId ||
5137                         foundDep->refobjid != attTup->atttypid)
5138                         elog(ERROR, "found unexpected dependency for column");
5139
5140                 simple_heap_delete(depRel, &depTup->t_self);
5141         }
5142
5143         systable_endscan(scan);
5144
5145         heap_close(depRel, RowExclusiveLock);
5146
5147         /*
5148          * Here we go --- change the recorded column type.      (Note heapTup is a
5149          * copy of the syscache entry, so okay to scribble on.)
5150          */
5151         attTup->atttypid = targettype;
5152         attTup->atttypmod = typename->typmod;
5153         attTup->attndims = list_length(typename->arrayBounds);
5154         attTup->attlen = tform->typlen;
5155         attTup->attbyval = tform->typbyval;
5156         attTup->attalign = tform->typalign;
5157         attTup->attstorage = tform->typstorage;
5158
5159         ReleaseSysCache(typeTuple);
5160
5161         simple_heap_update(attrelation, &heapTup->t_self, heapTup);
5162
5163         /* keep system catalog indexes current */
5164         CatalogUpdateIndexes(attrelation, heapTup);
5165
5166         heap_close(attrelation, RowExclusiveLock);
5167
5168         /* Install dependency on new datatype */
5169         add_column_datatype_dependency(RelationGetRelid(rel), attnum, targettype);
5170
5171         /*
5172          * Drop any pg_statistic entry for the column, since it's now wrong type
5173          */
5174         RemoveStatistics(RelationGetRelid(rel), attnum);
5175
5176         /*
5177          * Update the default, if present, by brute force --- remove and re-add
5178          * the default.  Probably unsafe to take shortcuts, since the new version
5179          * may well have additional dependencies.  (It's okay to do this now,
5180          * rather than after other ALTER TYPE commands, since the default won't
5181          * depend on other column types.)
5182          */
5183         if (defaultexpr)
5184         {
5185                 /* Must make new row visible since it will be updated again */
5186                 CommandCounterIncrement();
5187
5188                 /*
5189                  * We use RESTRICT here for safety, but at present we do not expect
5190                  * anything to depend on the default.
5191                  */
5192                 RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT, true);
5193
5194                 StoreAttrDefault(rel, attnum, nodeToString(defaultexpr));
5195         }
5196
5197         /* Cleanup */
5198         heap_freetuple(heapTup);
5199 }
5200
5201 /*
5202  * Cleanup after we've finished all the ALTER TYPE operations for a
5203  * particular relation.  We have to drop and recreate all the indexes
5204  * and constraints that depend on the altered columns.
5205  */
5206 static void
5207 ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab)
5208 {
5209         ObjectAddress obj;
5210         ListCell   *l;
5211
5212         /*
5213          * Re-parse the index and constraint definitions, and attach them to the
5214          * appropriate work queue entries.      We do this before dropping because in
5215          * the case of a FOREIGN KEY constraint, we might not yet have exclusive
5216          * lock on the table the constraint is attached to, and we need to get
5217          * that before dropping.  It's safe because the parser won't actually look
5218          * at the catalogs to detect the existing entry.
5219          */
5220         foreach(l, tab->changedIndexDefs)
5221                 ATPostAlterTypeParse((char *) lfirst(l), wqueue);
5222         foreach(l, tab->changedConstraintDefs)
5223                 ATPostAlterTypeParse((char *) lfirst(l), wqueue);
5224
5225         /*
5226          * Now we can drop the existing constraints and indexes --- constraints
5227          * first, since some of them might depend on the indexes.  In fact, we
5228          * have to delete FOREIGN KEY constraints before UNIQUE constraints,
5229          * but we already ordered the constraint list to ensure that would happen.
5230          * It should be okay to use DROP_RESTRICT here, since nothing else should
5231          * be depending on these objects.
5232          */
5233         foreach(l, tab->changedConstraintOids)
5234         {
5235                 obj.classId = ConstraintRelationId;
5236                 obj.objectId = lfirst_oid(l);
5237                 obj.objectSubId = 0;
5238                 performDeletion(&obj, DROP_RESTRICT);
5239         }
5240
5241         foreach(l, tab->changedIndexOids)
5242         {
5243                 obj.classId = RelationRelationId;
5244                 obj.objectId = lfirst_oid(l);
5245                 obj.objectSubId = 0;
5246                 performDeletion(&obj, DROP_RESTRICT);
5247         }
5248
5249         /*
5250          * The objects will get recreated during subsequent passes over the work
5251          * queue.
5252          */
5253 }
5254
5255 static void
5256 ATPostAlterTypeParse(char *cmd, List **wqueue)
5257 {
5258         List       *raw_parsetree_list;
5259         List       *querytree_list;
5260         ListCell   *list_item;
5261
5262         /*
5263          * We expect that we only have to do raw parsing and parse analysis, not
5264          * any rule rewriting, since these will all be utility statements.
5265          */
5266         raw_parsetree_list = raw_parser(cmd);
5267         querytree_list = NIL;
5268         foreach(list_item, raw_parsetree_list)
5269         {
5270                 Node       *parsetree = (Node *) lfirst(list_item);
5271
5272                 querytree_list = list_concat(querytree_list,
5273                                                                          parse_analyze(parsetree, NULL, 0));
5274         }
5275
5276         /*
5277          * Attach each generated command to the proper place in the work queue.
5278          * Note this could result in creation of entirely new work-queue entries.
5279          */
5280         foreach(list_item, querytree_list)
5281         {
5282                 Query      *query = (Query *) lfirst(list_item);
5283                 Relation        rel;
5284                 AlteredTableInfo *tab;
5285
5286                 Assert(IsA(query, Query));
5287                 Assert(query->commandType == CMD_UTILITY);
5288                 switch (nodeTag(query->utilityStmt))
5289                 {
5290                         case T_IndexStmt:
5291                                 {
5292                                         IndexStmt  *stmt = (IndexStmt *) query->utilityStmt;
5293                                         AlterTableCmd *newcmd;
5294
5295                                         rel = relation_openrv(stmt->relation, AccessExclusiveLock);
5296                                         tab = ATGetQueueEntry(wqueue, rel);
5297                                         newcmd = makeNode(AlterTableCmd);
5298                                         newcmd->subtype = AT_ReAddIndex;
5299                                         newcmd->def = (Node *) stmt;
5300                                         tab->subcmds[AT_PASS_OLD_INDEX] =
5301                                                 lappend(tab->subcmds[AT_PASS_OLD_INDEX], newcmd);
5302                                         relation_close(rel, NoLock);
5303                                         break;
5304                                 }
5305                         case T_AlterTableStmt:
5306                                 {
5307                                         AlterTableStmt *stmt = (AlterTableStmt *) query->utilityStmt;
5308                                         ListCell   *lcmd;
5309
5310                                         rel = relation_openrv(stmt->relation, AccessExclusiveLock);
5311                                         tab = ATGetQueueEntry(wqueue, rel);
5312                                         foreach(lcmd, stmt->cmds)
5313                                         {
5314                                                 AlterTableCmd *cmd = (AlterTableCmd *) lfirst(lcmd);
5315
5316                                                 switch (cmd->subtype)
5317                                                 {
5318                                                         case AT_AddIndex:
5319                                                                 cmd->subtype = AT_ReAddIndex;
5320                                                                 tab->subcmds[AT_PASS_OLD_INDEX] =
5321                                                                         lappend(tab->subcmds[AT_PASS_OLD_INDEX], cmd);
5322                                                                 break;
5323                                                         case AT_AddConstraint:
5324                                                                 tab->subcmds[AT_PASS_OLD_CONSTR] =
5325                                                                         lappend(tab->subcmds[AT_PASS_OLD_CONSTR], cmd);
5326                                                                 break;
5327                                                         default:
5328                                                                 elog(ERROR, "unexpected statement type: %d",
5329                                                                          (int) cmd->subtype);
5330                                                 }
5331                                         }
5332                                         relation_close(rel, NoLock);
5333                                         break;
5334                                 }
5335                         default:
5336                                 elog(ERROR, "unexpected statement type: %d",
5337                                          (int) nodeTag(query->utilityStmt));
5338                 }
5339         }
5340 }
5341
5342
5343 /*
5344  * ALTER TABLE OWNER
5345  *
5346  * recursing is true if we are recursing from a table to its indexes or
5347  * toast table.  We don't allow the ownership of those things to be
5348  * changed separately from the parent table.  Also, we can skip permission
5349  * checks (this is necessary not just an optimization, else we'd fail to
5350  * handle toast tables properly).
5351  */
5352 void
5353 ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing)
5354 {
5355         Relation        target_rel;
5356         Relation        class_rel;
5357         HeapTuple       tuple;
5358         Form_pg_class tuple_class;
5359
5360         /*
5361          * Get exclusive lock till end of transaction on the target table. Use
5362          * relation_open so that we can work on indexes and sequences.
5363          */
5364         target_rel = relation_open(relationOid, AccessExclusiveLock);
5365
5366         /* Get its pg_class tuple, too */
5367         class_rel = heap_open(RelationRelationId, RowExclusiveLock);
5368
5369         tuple = SearchSysCache(RELOID,
5370                                                    ObjectIdGetDatum(relationOid),
5371                                                    0, 0, 0);
5372         if (!HeapTupleIsValid(tuple))
5373                 elog(ERROR, "cache lookup failed for relation %u", relationOid);
5374         tuple_class = (Form_pg_class) GETSTRUCT(tuple);
5375
5376         /* Can we change the ownership of this tuple? */
5377         switch (tuple_class->relkind)
5378         {
5379                 case RELKIND_RELATION:
5380                 case RELKIND_VIEW:
5381                 case RELKIND_SEQUENCE:
5382                         /* ok to change owner */
5383                         break;
5384                 case RELKIND_INDEX:
5385                         if (!recursing)
5386                         {
5387                                 /*
5388                                  * Because ALTER INDEX OWNER used to be allowed, and in fact
5389                                  * is generated by old versions of pg_dump, we give a warning
5390                                  * and do nothing rather than erroring out.  Also, to avoid
5391                                  * unnecessary chatter while restoring those old dumps, say
5392                                  * nothing at all if the command would be a no-op anyway.
5393                                  */
5394                                 if (tuple_class->relowner != newOwnerId)
5395                                         ereport(WARNING,
5396                                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
5397                                                          errmsg("cannot change owner of index \"%s\"",
5398                                                                         NameStr(tuple_class->relname)),
5399                                                          errhint("Change the ownership of the index's table, instead.")));
5400                                 /* quick hack to exit via the no-op path */
5401                                 newOwnerId = tuple_class->relowner;
5402                         }
5403                         break;
5404                 case RELKIND_TOASTVALUE:
5405                         if (recursing)
5406                                 break;
5407                         /* FALL THRU */
5408                 default:
5409                         ereport(ERROR,
5410                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
5411                                          errmsg("\"%s\" is not a table, view, or sequence",
5412                                                         NameStr(tuple_class->relname))));
5413         }
5414
5415         /*
5416          * If the new owner is the same as the existing owner, consider the
5417          * command to have succeeded.  This is for dump restoration purposes.
5418          */
5419         if (tuple_class->relowner != newOwnerId)
5420         {
5421                 Datum           repl_val[Natts_pg_class];
5422                 char            repl_null[Natts_pg_class];
5423                 char            repl_repl[Natts_pg_class];
5424                 Acl                *newAcl;
5425                 Datum           aclDatum;
5426                 bool            isNull;
5427                 HeapTuple       newtuple;
5428
5429                 /* skip permission checks when recursing to index or toast table */
5430                 if (!recursing)
5431                 {
5432                         /* Superusers can always do it */
5433                         if (!superuser())
5434                         {
5435                                 Oid                     namespaceOid = tuple_class->relnamespace;
5436                                 AclResult       aclresult;
5437
5438                                 /* Otherwise, must be owner of the existing object */
5439                                 if (!pg_class_ownercheck(relationOid, GetUserId()))
5440                                         aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
5441                                                                    RelationGetRelationName(target_rel));
5442
5443                                 /* Must be able to become new owner */
5444                                 check_is_member_of_role(GetUserId(), newOwnerId);
5445
5446                                 /* New owner must have CREATE privilege on namespace */
5447                                 aclresult = pg_namespace_aclcheck(namespaceOid, newOwnerId,
5448                                                                                                   ACL_CREATE);
5449                                 if (aclresult != ACLCHECK_OK)
5450                                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
5451                                                                    get_namespace_name(namespaceOid));
5452                         }
5453                 }
5454
5455                 memset(repl_null, ' ', sizeof(repl_null));
5456                 memset(repl_repl, ' ', sizeof(repl_repl));
5457
5458                 repl_repl[Anum_pg_class_relowner - 1] = 'r';
5459                 repl_val[Anum_pg_class_relowner - 1] = ObjectIdGetDatum(newOwnerId);
5460
5461                 /*
5462                  * Determine the modified ACL for the new owner.  This is only
5463                  * necessary when the ACL is non-null.
5464                  */
5465                 aclDatum = SysCacheGetAttr(RELOID, tuple,
5466                                                                    Anum_pg_class_relacl,
5467                                                                    &isNull);
5468                 if (!isNull)
5469                 {
5470                         newAcl = aclnewowner(DatumGetAclP(aclDatum),
5471                                                                  tuple_class->relowner, newOwnerId);
5472                         repl_repl[Anum_pg_class_relacl - 1] = 'r';
5473                         repl_val[Anum_pg_class_relacl - 1] = PointerGetDatum(newAcl);
5474                 }
5475
5476                 newtuple = heap_modifytuple(tuple, RelationGetDescr(class_rel), repl_val, repl_null, repl_repl);
5477
5478                 simple_heap_update(class_rel, &newtuple->t_self, newtuple);
5479                 CatalogUpdateIndexes(class_rel, newtuple);
5480
5481                 heap_freetuple(newtuple);
5482
5483                 /* Update owner dependency reference */
5484                 changeDependencyOnOwner(RelationRelationId, relationOid, newOwnerId);
5485
5486                 /*
5487                  * Also change the ownership of the table's rowtype, if it has one
5488                  */
5489                 if (tuple_class->relkind != RELKIND_INDEX)
5490                         AlterTypeOwnerInternal(tuple_class->reltype, newOwnerId);
5491
5492                 /*
5493                  * If we are operating on a table, also change the ownership of any
5494                  * indexes and sequences that belong to the table, as well as the
5495                  * table's toast table (if it has one)
5496                  */
5497                 if (tuple_class->relkind == RELKIND_RELATION ||
5498                         tuple_class->relkind == RELKIND_TOASTVALUE)
5499                 {
5500                         List       *index_oid_list;
5501                         ListCell   *i;
5502
5503                         /* Find all the indexes belonging to this relation */
5504                         index_oid_list = RelationGetIndexList(target_rel);
5505
5506                         /* For each index, recursively change its ownership */
5507                         foreach(i, index_oid_list)
5508                                 ATExecChangeOwner(lfirst_oid(i), newOwnerId, true);
5509
5510                         list_free(index_oid_list);
5511                 }
5512
5513                 if (tuple_class->relkind == RELKIND_RELATION)
5514                 {
5515                         /* If it has a toast table, recurse to change its ownership */
5516                         if (tuple_class->reltoastrelid != InvalidOid)
5517                                 ATExecChangeOwner(tuple_class->reltoastrelid, newOwnerId,
5518                                                                   true);
5519
5520                         /* If it has dependent sequences, recurse to change them too */
5521                         change_owner_recurse_to_sequences(relationOid, newOwnerId);
5522                 }
5523         }
5524
5525         ReleaseSysCache(tuple);
5526         heap_close(class_rel, RowExclusiveLock);
5527         relation_close(target_rel, NoLock);
5528 }
5529
5530 /*
5531  * change_owner_recurse_to_sequences
5532  *
5533  * Helper function for ATExecChangeOwner.  Examines pg_depend searching
5534  * for sequences that are dependent on serial columns, and changes their
5535  * ownership.
5536  */
5537 static void
5538 change_owner_recurse_to_sequences(Oid relationOid, Oid newOwnerId)
5539 {
5540         Relation        depRel;
5541         SysScanDesc scan;
5542         ScanKeyData key[2];
5543         HeapTuple       tup;
5544
5545         /*
5546          * SERIAL sequences are those having an internal dependency on one of the
5547          * table's columns (we don't care *which* column, exactly).
5548          */
5549         depRel = heap_open(DependRelationId, AccessShareLock);
5550
5551         ScanKeyInit(&key[0],
5552                                 Anum_pg_depend_refclassid,
5553                                 BTEqualStrategyNumber, F_OIDEQ,
5554                                 ObjectIdGetDatum(RelationRelationId));
5555         ScanKeyInit(&key[1],
5556                                 Anum_pg_depend_refobjid,
5557                                 BTEqualStrategyNumber, F_OIDEQ,
5558                                 ObjectIdGetDatum(relationOid));
5559         /* we leave refobjsubid unspecified */
5560
5561         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
5562                                                           SnapshotNow, 2, key);
5563
5564         while (HeapTupleIsValid(tup = systable_getnext(scan)))
5565         {
5566                 Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
5567                 Relation        seqRel;
5568
5569                 /* skip dependencies other than internal dependencies on columns */
5570                 if (depForm->refobjsubid == 0 ||
5571                         depForm->classid != RelationRelationId ||
5572                         depForm->objsubid != 0 ||
5573                         depForm->deptype != DEPENDENCY_INTERNAL)
5574                         continue;
5575
5576                 /* Use relation_open just in case it's an index */
5577                 seqRel = relation_open(depForm->objid, AccessExclusiveLock);
5578
5579                 /* skip non-sequence relations */
5580                 if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
5581                 {
5582                         /* No need to keep the lock */
5583                         relation_close(seqRel, AccessExclusiveLock);
5584                         continue;
5585                 }
5586
5587                 /* We don't need to close the sequence while we alter it. */
5588                 ATExecChangeOwner(depForm->objid, newOwnerId, false);
5589
5590                 /* Now we can close it.  Keep the lock till end of transaction. */
5591                 relation_close(seqRel, NoLock);
5592         }
5593
5594         systable_endscan(scan);
5595
5596         relation_close(depRel, AccessShareLock);
5597 }
5598
5599 /*
5600  * ALTER TABLE CLUSTER ON
5601  *
5602  * The only thing we have to do is to change the indisclustered bits.
5603  */
5604 static void
5605 ATExecClusterOn(Relation rel, const char *indexName)
5606 {
5607         Oid                     indexOid;
5608
5609         indexOid = get_relname_relid(indexName, rel->rd_rel->relnamespace);
5610
5611         if (!OidIsValid(indexOid))
5612                 ereport(ERROR,
5613                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
5614                                  errmsg("index \"%s\" for table \"%s\" does not exist",
5615                                                 indexName, RelationGetRelationName(rel))));
5616
5617         /* Check index is valid to cluster on */
5618         check_index_is_clusterable(rel, indexOid, false);
5619
5620         /* And do the work */
5621         mark_index_clustered(rel, indexOid);
5622 }
5623
5624 /*
5625  * ALTER TABLE SET WITHOUT CLUSTER
5626  *
5627  * We have to find any indexes on the table that have indisclustered bit
5628  * set and turn it off.
5629  */
5630 static void
5631 ATExecDropCluster(Relation rel)
5632 {
5633         mark_index_clustered(rel, InvalidOid);
5634 }
5635
5636 /*
5637  * ALTER TABLE SET TABLESPACE
5638  */
5639 static void
5640 ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel, char *tablespacename)
5641 {
5642         Oid                     tablespaceId;
5643         AclResult       aclresult;
5644
5645         /*
5646          * We do our own permission checking because we want to allow this on
5647          * indexes.
5648          */
5649         if (rel->rd_rel->relkind != RELKIND_RELATION &&
5650                 rel->rd_rel->relkind != RELKIND_INDEX)
5651                 ereport(ERROR,
5652                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
5653                                  errmsg("\"%s\" is not a table or index",
5654                                                 RelationGetRelationName(rel))));
5655
5656         /* Permissions checks */
5657         if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
5658                 aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
5659                                            RelationGetRelationName(rel));
5660
5661         if (!allowSystemTableMods && IsSystemRelation(rel))
5662                 ereport(ERROR,
5663                                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
5664                                  errmsg("permission denied: \"%s\" is a system catalog",
5665                                                 RelationGetRelationName(rel))));
5666
5667         /* Check that the tablespace exists */
5668         tablespaceId = get_tablespace_oid(tablespacename);
5669         if (!OidIsValid(tablespaceId))
5670                 ereport(ERROR,
5671                                 (errcode(ERRCODE_UNDEFINED_OBJECT),
5672                                  errmsg("tablespace \"%s\" does not exist", tablespacename)));
5673
5674         /* Check its permissions */
5675         aclresult = pg_tablespace_aclcheck(tablespaceId, GetUserId(), ACL_CREATE);
5676         if (aclresult != ACLCHECK_OK)
5677                 aclcheck_error(aclresult, ACL_KIND_TABLESPACE, tablespacename);
5678
5679         /* Save info for Phase 3 to do the real work */
5680         if (OidIsValid(tab->newTableSpace))
5681                 ereport(ERROR,
5682                                 (errcode(ERRCODE_SYNTAX_ERROR),
5683                                  errmsg("cannot have multiple SET TABLESPACE subcommands")));
5684         tab->newTableSpace = tablespaceId;
5685 }
5686
5687 /*
5688  * Execute ALTER TABLE SET TABLESPACE for cases where there is no tuple
5689  * rewriting to be done, so we just want to copy the data as fast as possible.
5690  */
5691 static void
5692 ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
5693 {
5694         Relation        rel;
5695         Oid                     oldTableSpace;
5696         Oid                     reltoastrelid;
5697         Oid                     reltoastidxid;
5698         RelFileNode newrnode;
5699         SMgrRelation dstrel;
5700         Relation        pg_class;
5701         HeapTuple       tuple;
5702         Form_pg_class rd_rel;
5703
5704         rel = relation_open(tableOid, NoLock);
5705
5706         /*
5707          * We can never allow moving of shared or nailed-in-cache relations,
5708          * because we can't support changing their reltablespace values.
5709          */
5710         if (rel->rd_rel->relisshared || rel->rd_isnailed)
5711                 ereport(ERROR,
5712                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5713                                  errmsg("cannot move system relation \"%s\"",
5714                                                 RelationGetRelationName(rel))));
5715
5716         /*
5717          * Don't allow moving temp tables of other backends ... their local buffer
5718          * manager is not going to cope.
5719          */
5720         if (isOtherTempNamespace(RelationGetNamespace(rel)))
5721                 ereport(ERROR,
5722                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5723                                  errmsg("cannot move temporary tables of other sessions")));
5724
5725         /*
5726          * No work if no change in tablespace.
5727          */
5728         oldTableSpace = rel->rd_rel->reltablespace;
5729         if (newTableSpace == oldTableSpace ||
5730                 (newTableSpace == MyDatabaseTableSpace && oldTableSpace == 0))
5731         {
5732                 relation_close(rel, NoLock);
5733                 return;
5734         }
5735
5736         reltoastrelid = rel->rd_rel->reltoastrelid;
5737         reltoastidxid = rel->rd_rel->reltoastidxid;
5738
5739         /* Get a modifiable copy of the relation's pg_class row */
5740         pg_class = heap_open(RelationRelationId, RowExclusiveLock);
5741
5742         tuple = SearchSysCacheCopy(RELOID,
5743                                                            ObjectIdGetDatum(tableOid),
5744                                                            0, 0, 0);
5745         if (!HeapTupleIsValid(tuple))
5746                 elog(ERROR, "cache lookup failed for relation %u", tableOid);
5747         rd_rel = (Form_pg_class) GETSTRUCT(tuple);
5748
5749         /* create another storage file. Is it a little ugly ? */
5750         /* NOTE: any conflict in relfilenode value will be caught here */
5751         newrnode = rel->rd_node;
5752         newrnode.spcNode = newTableSpace;
5753
5754         dstrel = smgropen(newrnode);
5755         smgrcreate(dstrel, rel->rd_istemp, false);
5756
5757         /* copy relation data to the new physical file */
5758         copy_relation_data(rel, dstrel);
5759
5760         /* schedule unlinking old physical file */
5761         RelationOpenSmgr(rel);
5762         smgrscheduleunlink(rel->rd_smgr, rel->rd_istemp);
5763
5764         /*
5765          * Now drop smgr references.  The source was already dropped by
5766          * smgrscheduleunlink.
5767          */
5768         smgrclose(dstrel);
5769
5770         /* update the pg_class row */
5771         rd_rel->reltablespace = (newTableSpace == MyDatabaseTableSpace) ? InvalidOid : newTableSpace;
5772         simple_heap_update(pg_class, &tuple->t_self, tuple);
5773         CatalogUpdateIndexes(pg_class, tuple);
5774
5775         heap_freetuple(tuple);
5776
5777         heap_close(pg_class, RowExclusiveLock);
5778
5779         relation_close(rel, NoLock);
5780
5781         /* Make sure the reltablespace change is visible */
5782         CommandCounterIncrement();
5783
5784         /* Move associated toast relation and/or index, too */
5785         if (OidIsValid(reltoastrelid))
5786                 ATExecSetTableSpace(reltoastrelid, newTableSpace);
5787         if (OidIsValid(reltoastidxid))
5788                 ATExecSetTableSpace(reltoastidxid, newTableSpace);
5789 }
5790
5791 /*
5792  * Copy data, block by block
5793  */
5794 static void
5795 copy_relation_data(Relation rel, SMgrRelation dst)
5796 {
5797         SMgrRelation src;
5798         bool            use_wal;
5799         BlockNumber nblocks;
5800         BlockNumber blkno;
5801         char            buf[BLCKSZ];
5802         Page            page = (Page) buf;
5803
5804         /*
5805          * Since we copy the file directly without looking at the shared buffers,
5806          * we'd better first flush out any pages of the source relation that are
5807          * in shared buffers.  We assume no new changes will be made while we are
5808          * holding exclusive lock on the rel.
5809          */
5810         FlushRelationBuffers(rel);
5811
5812         /*
5813          * We need to log the copied data in WAL iff WAL archiving is enabled AND
5814          * it's not a temp rel.
5815          */
5816         use_wal = XLogArchivingActive() && !rel->rd_istemp;
5817
5818         nblocks = RelationGetNumberOfBlocks(rel);
5819         /* RelationGetNumberOfBlocks will certainly have opened rd_smgr */
5820         src = rel->rd_smgr;
5821
5822         for (blkno = 0; blkno < nblocks; blkno++)
5823         {
5824                 smgrread(src, blkno, buf);
5825
5826                 /* XLOG stuff */
5827                 if (use_wal)
5828                 {
5829                         xl_heap_newpage xlrec;
5830                         XLogRecPtr      recptr;
5831                         XLogRecData rdata[2];
5832
5833                         /* NO ELOG(ERROR) from here till newpage op is logged */
5834                         START_CRIT_SECTION();
5835
5836                         xlrec.node = dst->smgr_rnode;
5837                         xlrec.blkno = blkno;
5838
5839                         rdata[0].data = (char *) &xlrec;
5840                         rdata[0].len = SizeOfHeapNewpage;
5841                         rdata[0].buffer = InvalidBuffer;
5842                         rdata[0].next = &(rdata[1]);
5843
5844                         rdata[1].data = (char *) page;
5845                         rdata[1].len = BLCKSZ;
5846                         rdata[1].buffer = InvalidBuffer;
5847                         rdata[1].next = NULL;
5848
5849                         recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_NEWPAGE, rdata);
5850
5851                         PageSetLSN(page, recptr);
5852                         PageSetTLI(page, ThisTimeLineID);
5853
5854                         END_CRIT_SECTION();
5855                 }
5856
5857                 /*
5858                  * Now write the page.  We say isTemp = true even if it's not a temp
5859                  * rel, because there's no need for smgr to schedule an fsync for this
5860                  * write; we'll do it ourselves below.
5861                  */
5862                 smgrwrite(dst, blkno, buf, true);
5863         }
5864
5865         /*
5866          * If the rel isn't temp, we must fsync it down to disk before it's safe
5867          * to commit the transaction.  (For a temp rel we don't care since the rel
5868          * will be uninteresting after a crash anyway.)
5869          *
5870          * It's obvious that we must do this when not WAL-logging the copy. It's
5871          * less obvious that we have to do it even if we did WAL-log the copied
5872          * pages. The reason is that since we're copying outside shared buffers, a
5873          * CHECKPOINT occurring during the copy has no way to flush the previously
5874          * written data to disk (indeed it won't know the new rel even exists).  A
5875          * crash later on would replay WAL from the checkpoint, therefore it
5876          * wouldn't replay our earlier WAL entries. If we do not fsync those pages
5877          * here, they might still not be on disk when the crash occurs.
5878          */
5879         if (!rel->rd_istemp)
5880                 smgrimmedsync(dst);
5881 }
5882
5883 /*
5884  * ALTER TABLE ENABLE/DISABLE TRIGGER
5885  *
5886  * We just pass this off to trigger.c.
5887  */
5888 static void
5889 ATExecEnableDisableTrigger(Relation rel, char *trigname,
5890                                                    bool enable, bool skip_system)
5891 {
5892         EnableDisableTrigger(rel, trigname, enable, skip_system);
5893 }
5894
5895 /*
5896  * ALTER TABLE CREATE TOAST TABLE
5897  *
5898  * Note: this is also invoked from outside this module; in such cases we
5899  * expect the caller to have verified that the relation is a table and we
5900  * have all the right permissions.      Callers expect this function
5901  * to end with CommandCounterIncrement if it makes any changes.
5902  */
5903 void
5904 AlterTableCreateToastTable(Oid relOid, bool silent)
5905 {
5906         Relation        rel;
5907         HeapTuple       reltup;
5908         TupleDesc       tupdesc;
5909         bool            shared_relation;
5910         Relation        class_rel;
5911         Oid                     toast_relid;
5912         Oid                     toast_idxid;
5913         char            toast_relname[NAMEDATALEN];
5914         char            toast_idxname[NAMEDATALEN];
5915         IndexInfo  *indexInfo;
5916         Oid                     classObjectId[2];
5917         ObjectAddress baseobject,
5918                                 toastobject;
5919
5920         /*
5921          * Grab an exclusive lock on the target table, which we will NOT release
5922          * until end of transaction.  (This is probably redundant in all present
5923          * uses...)
5924          */
5925         rel = heap_open(relOid, AccessExclusiveLock);
5926
5927         /*
5928          * Toast table is shared if and only if its parent is.
5929          *
5930          * We cannot allow toasting a shared relation after initdb (because
5931          * there's no way to mark it toasted in other databases' pg_class).
5932          * Unfortunately we can't distinguish initdb from a manually started
5933          * standalone backend (toasting happens after the bootstrap phase, so
5934          * checking IsBootstrapProcessingMode() won't work).  However, we can at
5935          * least prevent this mistake under normal multi-user operation.
5936          */
5937         shared_relation = rel->rd_rel->relisshared;
5938         if (shared_relation && IsUnderPostmaster)
5939                 ereport(ERROR,
5940                                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5941                                  errmsg("shared tables cannot be toasted after initdb")));
5942
5943         /*
5944          * Is it already toasted?
5945          */
5946         if (rel->rd_rel->reltoastrelid != InvalidOid)
5947         {
5948                 if (silent)
5949                 {
5950                         heap_close(rel, NoLock);
5951                         return;
5952                 }
5953
5954                 ereport(ERROR,
5955                                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5956                                  errmsg("table \"%s\" already has a TOAST table",
5957                                                 RelationGetRelationName(rel))));
5958         }
5959
5960         /*
5961          * Check to see whether the table actually needs a TOAST table.
5962          */
5963         if (!needs_toast_table(rel))
5964         {
5965                 if (silent)
5966                 {
5967                         heap_close(rel, NoLock);
5968                         return;
5969                 }
5970
5971                 ereport(ERROR,
5972                                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
5973                                  errmsg("table \"%s\" does not need a TOAST table",
5974                                                 RelationGetRelationName(rel))));
5975         }
5976
5977         /*
5978          * Create the toast table and its index
5979          */
5980         snprintf(toast_relname, sizeof(toast_relname),
5981                          "pg_toast_%u", relOid);
5982         snprintf(toast_idxname, sizeof(toast_idxname),
5983                          "pg_toast_%u_index", relOid);
5984
5985         /* this is pretty painful...  need a tuple descriptor */
5986         tupdesc = CreateTemplateTupleDesc(3, false);
5987         TupleDescInitEntry(tupdesc, (AttrNumber) 1,
5988                                            "chunk_id",
5989                                            OIDOID,
5990                                            -1, 0);
5991         TupleDescInitEntry(tupdesc, (AttrNumber) 2,
5992                                            "chunk_seq",
5993                                            INT4OID,
5994                                            -1, 0);
5995         TupleDescInitEntry(tupdesc, (AttrNumber) 3,
5996                                            "chunk_data",
5997                                            BYTEAOID,
5998                                            -1, 0);
5999
6000         /*
6001          * Ensure that the toast table doesn't itself get toasted, or we'll be
6002          * toast :-(.  This is essential for chunk_data because type bytea is
6003          * toastable; hit the other two just to be sure.
6004          */
6005         tupdesc->attrs[0]->attstorage = 'p';
6006         tupdesc->attrs[1]->attstorage = 'p';
6007         tupdesc->attrs[2]->attstorage = 'p';
6008
6009         /*
6010          * Note: the toast relation is placed in the regular pg_toast namespace
6011          * even if its master relation is a temp table.  There cannot be any
6012          * naming collision, and the toast rel will be destroyed when its master
6013          * is, so there's no need to handle the toast rel as temp.
6014          */
6015         toast_relid = heap_create_with_catalog(toast_relname,
6016                                                                                    PG_TOAST_NAMESPACE,
6017                                                                                    rel->rd_rel->reltablespace,
6018                                                                                    InvalidOid,
6019                                                                                    rel->rd_rel->relowner,
6020                                                                                    tupdesc,
6021                                                                                    RELKIND_TOASTVALUE,
6022                                                                                    shared_relation,
6023                                                                                    true,
6024                                                                                    0,
6025                                                                                    ONCOMMIT_NOOP,
6026                                                                                    true);
6027
6028         /* make the toast relation visible, else index creation will fail */
6029         CommandCounterIncrement();
6030
6031         /*
6032          * Create unique index on chunk_id, chunk_seq.
6033          *
6034          * NOTE: the normal TOAST access routines could actually function with a
6035          * single-column index on chunk_id only. However, the slice access
6036          * routines use both columns for faster access to an individual chunk. In
6037          * addition, we want it to be unique as a check against the possibility of
6038          * duplicate TOAST chunk OIDs. The index might also be a little more
6039          * efficient this way, since btree isn't all that happy with large numbers
6040          * of equal keys.
6041          */
6042
6043         indexInfo = makeNode(IndexInfo);
6044         indexInfo->ii_NumIndexAttrs = 2;
6045         indexInfo->ii_KeyAttrNumbers[0] = 1;
6046         indexInfo->ii_KeyAttrNumbers[1] = 2;
6047         indexInfo->ii_Expressions = NIL;
6048         indexInfo->ii_ExpressionsState = NIL;
6049         indexInfo->ii_Predicate = NIL;
6050         indexInfo->ii_PredicateState = NIL;
6051         indexInfo->ii_Unique = true;
6052
6053         classObjectId[0] = OID_BTREE_OPS_OID;
6054         classObjectId[1] = INT4_BTREE_OPS_OID;
6055
6056         toast_idxid = index_create(toast_relid, toast_idxname, InvalidOid,
6057                                                            indexInfo,
6058                                                            BTREE_AM_OID,
6059                                                            rel->rd_rel->reltablespace,
6060                                                            classObjectId,
6061                                                            true, false, true, false);
6062
6063         /*
6064          * Update toast rel's pg_class entry to show that it has an index. The
6065          * index OID is stored into the reltoastidxid field for easy access by the
6066          * tuple toaster.
6067          */
6068         setRelhasindex(toast_relid, true, true, toast_idxid);
6069
6070         /*
6071          * Store the toast table's OID in the parent relation's pg_class row
6072          */
6073         class_rel = heap_open(RelationRelationId, RowExclusiveLock);
6074
6075         reltup = SearchSysCacheCopy(RELOID,
6076                                                                 ObjectIdGetDatum(relOid),
6077                                                                 0, 0, 0);
6078         if (!HeapTupleIsValid(reltup))
6079                 elog(ERROR, "cache lookup failed for relation %u", relOid);
6080
6081         ((Form_pg_class) GETSTRUCT(reltup))->reltoastrelid = toast_relid;
6082
6083         simple_heap_update(class_rel, &reltup->t_self, reltup);
6084
6085         /* Keep catalog indexes current */
6086         CatalogUpdateIndexes(class_rel, reltup);
6087
6088         heap_freetuple(reltup);
6089
6090         heap_close(class_rel, RowExclusiveLock);
6091
6092         /*
6093          * Register dependency from the toast table to the master, so that the
6094          * toast table will be deleted if the master is.
6095          */
6096         baseobject.classId = RelationRelationId;
6097         baseobject.objectId = relOid;
6098         baseobject.objectSubId = 0;
6099         toastobject.classId = RelationRelationId;
6100         toastobject.objectId = toast_relid;
6101         toastobject.objectSubId = 0;
6102
6103         recordDependencyOn(&toastobject, &baseobject, DEPENDENCY_INTERNAL);
6104
6105         /*
6106          * Clean up and make changes visible
6107          */
6108         heap_close(rel, NoLock);
6109
6110         CommandCounterIncrement();
6111 }
6112
6113 /*
6114  * Check to see whether the table needs a TOAST table.  It does only if
6115  * (1) there are any toastable attributes, and (2) the maximum length
6116  * of a tuple could exceed TOAST_TUPLE_THRESHOLD.  (We don't want to
6117  * create a toast table for something like "f1 varchar(20)".)
6118  */
6119 static bool
6120 needs_toast_table(Relation rel)
6121 {
6122         int32           data_length = 0;
6123         bool            maxlength_unknown = false;
6124         bool            has_toastable_attrs = false;
6125         TupleDesc       tupdesc;
6126         Form_pg_attribute *att;
6127         int32           tuple_length;
6128         int                     i;
6129
6130         tupdesc = rel->rd_att;
6131         att = tupdesc->attrs;
6132
6133         for (i = 0; i < tupdesc->natts; i++)
6134         {
6135                 if (att[i]->attisdropped)
6136                         continue;
6137                 data_length = att_align(data_length, att[i]->attalign);
6138                 if (att[i]->attlen > 0)
6139                 {
6140                         /* Fixed-length types are never toastable */
6141                         data_length += att[i]->attlen;
6142                 }
6143                 else
6144                 {
6145                         int32           maxlen = type_maximum_size(att[i]->atttypid,
6146                                                                                                    att[i]->atttypmod);
6147
6148                         if (maxlen < 0)
6149                                 maxlength_unknown = true;
6150                         else
6151                                 data_length += maxlen;
6152                         if (att[i]->attstorage != 'p')
6153                                 has_toastable_attrs = true;
6154                 }
6155         }
6156         if (!has_toastable_attrs)
6157                 return false;                   /* nothing to toast? */
6158         if (maxlength_unknown)
6159                 return true;                    /* any unlimited-length attrs? */
6160         tuple_length = MAXALIGN(offsetof(HeapTupleHeaderData, t_bits) +
6161                                                         BITMAPLEN(tupdesc->natts)) +
6162                 MAXALIGN(data_length);
6163         return (tuple_length > TOAST_TUPLE_THRESHOLD);
6164 }
6165
6166
6167 /*
6168  * Execute ALTER TABLE SET SCHEMA
6169  *
6170  * Note: caller must have checked ownership of the relation already
6171  */
6172 void
6173 AlterTableNamespace(RangeVar *relation, const char *newschema)
6174 {
6175         Relation        rel;
6176         Oid                     relid;
6177         Oid                     oldNspOid;
6178         Oid                     nspOid;
6179         Relation        classRel;
6180
6181         rel = heap_openrv(relation, AccessExclusiveLock);
6182
6183         /* heap_openrv allows TOAST, but we don't want to */
6184         if (rel->rd_rel->relkind == RELKIND_TOASTVALUE)
6185                 ereport(ERROR,
6186                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
6187                                  errmsg("\"%s\" is a TOAST relation",
6188                                                 RelationGetRelationName(rel))));
6189
6190         relid = RelationGetRelid(rel);
6191         oldNspOid = RelationGetNamespace(rel);
6192
6193         /* get schema OID and check its permissions */
6194         nspOid = LookupCreationNamespace(newschema);
6195
6196         if (oldNspOid == nspOid)
6197                 ereport(ERROR,
6198                                 (errcode(ERRCODE_DUPLICATE_TABLE),
6199                                  errmsg("relation \"%s\" is already in schema \"%s\"",
6200                                                 RelationGetRelationName(rel),
6201                                                 newschema)));
6202
6203         /* disallow renaming into or out of temp schemas */
6204         if (isAnyTempNamespace(nspOid) || isAnyTempNamespace(oldNspOid))
6205                 ereport(ERROR,
6206                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
6207                         errmsg("cannot move objects into or out of temporary schemas")));
6208
6209         /* same for TOAST schema */
6210         if (nspOid == PG_TOAST_NAMESPACE || oldNspOid == PG_TOAST_NAMESPACE)
6211                 ereport(ERROR,
6212                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
6213                                  errmsg("cannot move objects into or out of TOAST schema")));
6214
6215         /* OK, modify the pg_class row and pg_depend entry */
6216         classRel = heap_open(RelationRelationId, RowExclusiveLock);
6217
6218         AlterRelationNamespaceInternal(classRel, relid, oldNspOid, nspOid, true);
6219
6220         /* Fix the table's rowtype too */
6221         AlterTypeNamespaceInternal(rel->rd_rel->reltype, nspOid, false);
6222
6223         /* Fix other dependent stuff */
6224         if (rel->rd_rel->relkind == RELKIND_RELATION)
6225         {
6226                 AlterIndexNamespaces(classRel, rel, oldNspOid, nspOid);
6227                 AlterSeqNamespaces(classRel, rel, oldNspOid, nspOid, newschema);
6228                 AlterConstraintNamespaces(relid, oldNspOid, nspOid, false);
6229         }
6230
6231         heap_close(classRel, RowExclusiveLock);
6232
6233         /* close rel, but keep lock until commit */
6234         relation_close(rel, NoLock);
6235 }
6236
6237 /*
6238  * The guts of relocating a relation to another namespace: fix the pg_class
6239  * entry, and the pg_depend entry if any.  Caller must already have
6240  * opened and write-locked pg_class.
6241  */
6242 void
6243 AlterRelationNamespaceInternal(Relation classRel, Oid relOid,
6244                                                            Oid oldNspOid, Oid newNspOid,
6245                                                            bool hasDependEntry)
6246 {
6247         HeapTuple       classTup;
6248         Form_pg_class classForm;
6249
6250         classTup = SearchSysCacheCopy(RELOID,
6251                                                                   ObjectIdGetDatum(relOid),
6252                                                                   0, 0, 0);
6253         if (!HeapTupleIsValid(classTup))
6254                 elog(ERROR, "cache lookup failed for relation %u", relOid);
6255         classForm = (Form_pg_class) GETSTRUCT(classTup);
6256
6257         Assert(classForm->relnamespace == oldNspOid);
6258
6259         /* check for duplicate name (more friendly than unique-index failure) */
6260         if (get_relname_relid(NameStr(classForm->relname),
6261                                                   newNspOid) != InvalidOid)
6262                 ereport(ERROR,
6263                                 (errcode(ERRCODE_DUPLICATE_TABLE),
6264                                  errmsg("relation \"%s\" already exists in schema \"%s\"",
6265                                                 NameStr(classForm->relname),
6266                                                 get_namespace_name(newNspOid))));
6267
6268         /* classTup is a copy, so OK to scribble on */
6269         classForm->relnamespace = newNspOid;
6270
6271         simple_heap_update(classRel, &classTup->t_self, classTup);
6272         CatalogUpdateIndexes(classRel, classTup);
6273
6274         /* Update dependency on schema if caller said so */
6275         if (hasDependEntry &&
6276                 changeDependencyFor(RelationRelationId, relOid,
6277                                                         NamespaceRelationId, oldNspOid, newNspOid) != 1)
6278                 elog(ERROR, "failed to change schema dependency for relation \"%s\"",
6279                          NameStr(classForm->relname));
6280
6281         heap_freetuple(classTup);
6282 }
6283
6284 /*
6285  * Move all indexes for the specified relation to another namespace.
6286  *
6287  * Note: we assume adequate permission checking was done by the caller,
6288  * and that the caller has a suitable lock on the owning relation.
6289  */
6290 static void
6291 AlterIndexNamespaces(Relation classRel, Relation rel,
6292                                          Oid oldNspOid, Oid newNspOid)
6293 {
6294         List       *indexList;
6295         ListCell   *l;
6296
6297         indexList = RelationGetIndexList(rel);
6298
6299         foreach(l, indexList)
6300         {
6301                 Oid                     indexOid = lfirst_oid(l);
6302
6303                 /*
6304                  * Note: currently, the index will not have its own dependency on the
6305                  * namespace, so we don't need to do changeDependencyFor(). There's no
6306                  * rowtype in pg_type, either.
6307                  */
6308                 AlterRelationNamespaceInternal(classRel, indexOid,
6309                                                                            oldNspOid, newNspOid,
6310                                                                            false);
6311         }
6312
6313         list_free(indexList);
6314 }
6315
6316 /*
6317  * Move all SERIAL-column sequences of the specified relation to another
6318  * namespace.
6319  *
6320  * Note: we assume adequate permission checking was done by the caller,
6321  * and that the caller has a suitable lock on the owning relation.
6322  */
6323 static void
6324 AlterSeqNamespaces(Relation classRel, Relation rel,
6325                                    Oid oldNspOid, Oid newNspOid, const char *newNspName)
6326 {
6327         Relation        depRel;
6328         SysScanDesc scan;
6329         ScanKeyData key[2];
6330         HeapTuple       tup;
6331
6332         /*
6333          * SERIAL sequences are those having an internal dependency on one of the
6334          * table's columns (we don't care *which* column, exactly).
6335          */
6336         depRel = heap_open(DependRelationId, AccessShareLock);
6337
6338         ScanKeyInit(&key[0],
6339                                 Anum_pg_depend_refclassid,
6340                                 BTEqualStrategyNumber, F_OIDEQ,
6341                                 ObjectIdGetDatum(RelationRelationId));
6342         ScanKeyInit(&key[1],
6343                                 Anum_pg_depend_refobjid,
6344                                 BTEqualStrategyNumber, F_OIDEQ,
6345                                 ObjectIdGetDatum(RelationGetRelid(rel)));
6346         /* we leave refobjsubid unspecified */
6347
6348         scan = systable_beginscan(depRel, DependReferenceIndexId, true,
6349                                                           SnapshotNow, 2, key);
6350
6351         while (HeapTupleIsValid(tup = systable_getnext(scan)))
6352         {
6353                 Form_pg_depend depForm = (Form_pg_depend) GETSTRUCT(tup);
6354                 Relation        seqRel;
6355
6356                 /* skip dependencies other than internal dependencies on columns */
6357                 if (depForm->refobjsubid == 0 ||
6358                         depForm->classid != RelationRelationId ||
6359                         depForm->objsubid != 0 ||
6360                         depForm->deptype != DEPENDENCY_INTERNAL)
6361                         continue;
6362
6363                 /* Use relation_open just in case it's an index */
6364                 seqRel = relation_open(depForm->objid, AccessExclusiveLock);
6365
6366                 /* skip non-sequence relations */
6367                 if (RelationGetForm(seqRel)->relkind != RELKIND_SEQUENCE)
6368                 {
6369                         /* No need to keep the lock */
6370                         relation_close(seqRel, AccessExclusiveLock);
6371                         continue;
6372                 }
6373
6374                 /* Fix the pg_class and pg_depend entries */
6375                 AlterRelationNamespaceInternal(classRel, depForm->objid,
6376                                                                            oldNspOid, newNspOid,
6377                                                                            true);
6378
6379                 /*
6380                  * Sequences have entries in pg_type. We need to be careful to move
6381                  * them to the new namespace, too.
6382                  */
6383                 AlterTypeNamespaceInternal(RelationGetForm(seqRel)->reltype,
6384                                                                    newNspOid, false);
6385
6386                 /* Now we can close it.  Keep the lock till end of transaction. */
6387                 relation_close(seqRel, NoLock);
6388         }
6389
6390         systable_endscan(scan);
6391
6392         relation_close(depRel, AccessShareLock);
6393 }
6394
6395
6396 /*
6397  * This code supports
6398  *      CREATE TEMP TABLE ... ON COMMIT { DROP | PRESERVE ROWS | DELETE ROWS }
6399  *
6400  * Because we only support this for TEMP tables, it's sufficient to remember
6401  * the state in a backend-local data structure.
6402  */
6403
6404 /*
6405  * Register a newly-created relation's ON COMMIT action.
6406  */
6407 void
6408 register_on_commit_action(Oid relid, OnCommitAction action)
6409 {
6410         OnCommitItem *oc;
6411         MemoryContext oldcxt;
6412
6413         /*
6414          * We needn't bother registering the relation unless there is an ON COMMIT
6415          * action we need to take.
6416          */
6417         if (action == ONCOMMIT_NOOP || action == ONCOMMIT_PRESERVE_ROWS)
6418                 return;
6419
6420         oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
6421
6422         oc = (OnCommitItem *) palloc(sizeof(OnCommitItem));
6423         oc->relid = relid;
6424         oc->oncommit = action;
6425         oc->creating_subid = GetCurrentSubTransactionId();
6426         oc->deleting_subid = InvalidSubTransactionId;
6427
6428         on_commits = lcons(oc, on_commits);
6429
6430         MemoryContextSwitchTo(oldcxt);
6431 }
6432
6433 /*
6434  * Unregister any ON COMMIT action when a relation is deleted.
6435  *
6436  * Actually, we only mark the OnCommitItem entry as to be deleted after commit.
6437  */
6438 void
6439 remove_on_commit_action(Oid relid)
6440 {
6441         ListCell   *l;
6442
6443         foreach(l, on_commits)
6444         {
6445                 OnCommitItem *oc = (OnCommitItem *) lfirst(l);
6446
6447                 if (oc->relid == relid)
6448                 {
6449                         oc->deleting_subid = GetCurrentSubTransactionId();
6450                         break;
6451                 }
6452         }
6453 }
6454
6455 /*
6456  * Perform ON COMMIT actions.
6457  *
6458  * This is invoked just before actually committing, since it's possible
6459  * to encounter errors.
6460  */
6461 void
6462 PreCommit_on_commit_actions(void)
6463 {
6464         ListCell   *l;
6465         List       *oids_to_truncate = NIL;
6466
6467         foreach(l, on_commits)
6468         {
6469                 OnCommitItem *oc = (OnCommitItem *) lfirst(l);
6470
6471                 /* Ignore entry if already dropped in this xact */
6472                 if (oc->deleting_subid != InvalidSubTransactionId)
6473                         continue;
6474
6475                 switch (oc->oncommit)
6476                 {
6477                         case ONCOMMIT_NOOP:
6478                         case ONCOMMIT_PRESERVE_ROWS:
6479                                 /* Do nothing (there shouldn't be such entries, actually) */
6480                                 break;
6481                         case ONCOMMIT_DELETE_ROWS:
6482                                 oids_to_truncate = lappend_oid(oids_to_truncate, oc->relid);
6483                                 break;
6484                         case ONCOMMIT_DROP:
6485                                 {
6486                                         ObjectAddress object;
6487
6488                                         object.classId = RelationRelationId;
6489                                         object.objectId = oc->relid;
6490                                         object.objectSubId = 0;
6491                                         performDeletion(&object, DROP_CASCADE);
6492
6493                                         /*
6494                                          * Note that table deletion will call
6495                                          * remove_on_commit_action, so the entry should get marked
6496                                          * as deleted.
6497                                          */
6498                                         Assert(oc->deleting_subid != InvalidSubTransactionId);
6499                                         break;
6500                                 }
6501                 }
6502         }
6503         if (oids_to_truncate != NIL)
6504         {
6505                 heap_truncate(oids_to_truncate);
6506                 CommandCounterIncrement();              /* XXX needed? */
6507         }
6508 }
6509
6510 /*
6511  * Post-commit or post-abort cleanup for ON COMMIT management.
6512  *
6513  * All we do here is remove no-longer-needed OnCommitItem entries.
6514  *
6515  * During commit, remove entries that were deleted during this transaction;
6516  * during abort, remove those created during this transaction.
6517  */
6518 void
6519 AtEOXact_on_commit_actions(bool isCommit)
6520 {
6521         ListCell   *cur_item;
6522         ListCell   *prev_item;
6523
6524         prev_item = NULL;
6525         cur_item = list_head(on_commits);
6526
6527         while (cur_item != NULL)
6528         {
6529                 OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
6530
6531                 if (isCommit ? oc->deleting_subid != InvalidSubTransactionId :
6532                         oc->creating_subid != InvalidSubTransactionId)
6533                 {
6534                         /* cur_item must be removed */
6535                         on_commits = list_delete_cell(on_commits, cur_item, prev_item);
6536                         pfree(oc);
6537                         if (prev_item)
6538                                 cur_item = lnext(prev_item);
6539                         else
6540                                 cur_item = list_head(on_commits);
6541                 }
6542                 else
6543                 {
6544                         /* cur_item must be preserved */
6545                         oc->creating_subid = InvalidSubTransactionId;
6546                         oc->deleting_subid = InvalidSubTransactionId;
6547                         prev_item = cur_item;
6548                         cur_item = lnext(prev_item);
6549                 }
6550         }
6551 }
6552
6553 /*
6554  * Post-subcommit or post-subabort cleanup for ON COMMIT management.
6555  *
6556  * During subabort, we can immediately remove entries created during this
6557  * subtransaction.      During subcommit, just relabel entries marked during
6558  * this subtransaction as being the parent's responsibility.
6559  */
6560 void
6561 AtEOSubXact_on_commit_actions(bool isCommit, SubTransactionId mySubid,
6562                                                           SubTransactionId parentSubid)
6563 {
6564         ListCell   *cur_item;
6565         ListCell   *prev_item;
6566
6567         prev_item = NULL;
6568         cur_item = list_head(on_commits);
6569
6570         while (cur_item != NULL)
6571         {
6572                 OnCommitItem *oc = (OnCommitItem *) lfirst(cur_item);
6573
6574                 if (!isCommit && oc->creating_subid == mySubid)
6575                 {
6576                         /* cur_item must be removed */
6577                         on_commits = list_delete_cell(on_commits, cur_item, prev_item);
6578                         pfree(oc);
6579                         if (prev_item)
6580                                 cur_item = lnext(prev_item);
6581                         else
6582                                 cur_item = list_head(on_commits);
6583                 }
6584                 else
6585                 {
6586                         /* cur_item must be preserved */
6587                         if (oc->creating_subid == mySubid)
6588                                 oc->creating_subid = parentSubid;
6589                         if (oc->deleting_subid == mySubid)
6590                                 oc->deleting_subid = isCommit ? parentSubid : InvalidSubTransactionId;
6591                         prev_item = cur_item;
6592                         cur_item = lnext(prev_item);
6593                 }
6594         }
6595 }