src/backend/optimizer/plan/setrefs.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * setrefs.c
   4  *        Post-processing of a completed plan tree: fix references to subplan
   5  *        vars, compute regproc values for operators, etc
   6  *
   7  * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
   8  * Portions Copyright (c) 1994, Regents of the University of California
   9  *
  10  *
  11  * IDENTIFICATION
  12  *        src/backend/optimizer/plan/setrefs.c
  13  *
  14  *-------------------------------------------------------------------------
  15  */
  16 #include "postgres.h"
  17
  18 #include "access/transam.h"
  19 #include "catalog/pg_type.h"
  20 #include "nodes/makefuncs.h"
  21 #include "nodes/nodeFuncs.h"
  22 #include "optimizer/clauses.h"
  23 #include "optimizer/planmain.h"
  24 #include "optimizer/tlist.h"
  25 #include "parser/parsetree.h"
  26 #include "utils/lsyscache.h"
  27 #include "utils/syscache.h"
  28
  29
  30 typedef struct
  31 {
  32         Index           varno;                  /* RT index of Var */
  33         AttrNumber      varattno;               /* attr number of Var */
  34         AttrNumber      resno;                  /* TLE position of Var */
  35 } tlist_vinfo;
  36
  37 typedef struct
  38 {
  39         List       *tlist;                      /* underlying target list */
  40         int                     num_vars;               /* number of plain Var tlist entries */
  41         bool            has_ph_vars;    /* are there PlaceHolderVar entries? */
  42         bool            has_non_vars;   /* are there other entries? */
  43         /* array of num_vars entries: */
  44         tlist_vinfo vars[1];            /* VARIABLE LENGTH ARRAY */
  45 } indexed_tlist;                                /* VARIABLE LENGTH STRUCT */
  46
  47 typedef struct
  48 {
  49         PlannerGlobal *glob;
  50         int                     rtoffset;
  51 } fix_scan_expr_context;
  52
  53 typedef struct
  54 {
  55         PlannerGlobal *glob;
  56         indexed_tlist *outer_itlist;
  57         indexed_tlist *inner_itlist;
  58         Index           acceptable_rel;
  59         int                     rtoffset;
  60 } fix_join_expr_context;
  61
  62 typedef struct
  63 {
  64         PlannerGlobal *glob;
  65         indexed_tlist *subplan_itlist;
  66         int                     rtoffset;
  67 } fix_upper_expr_context;
  68
  69 /*
  70  * Check if a Const node is a regclass value.  We accept plain OID too,
  71  * since a regclass Const will get folded to that type if it's an argument
  72  * to oideq or similar operators.  (This might result in some extraneous
  73  * values in a plan's list of relation dependencies, but the worst result
  74  * would be occasional useless replans.)
  75  */
  76 #define ISREGCLASSCONST(con) \
  77         (((con)->consttype == REGCLASSOID || (con)->consttype == OIDOID) && \
  78          !(con)->constisnull)
  79
  80 #define fix_scan_list(glob, lst, rtoffset) \
  81         ((List *) fix_scan_expr(glob, (Node *) (lst), rtoffset))
  82
  83 static Plan *set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset);
  84 static Plan *set_subqueryscan_references(PlannerGlobal *glob,
  85                                                         SubqueryScan *plan,
  86                                                         int rtoffset);
  87 static bool trivial_subqueryscan(SubqueryScan *plan);
  88 static Node *fix_scan_expr(PlannerGlobal *glob, Node *node, int rtoffset);
  89 static Node *fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context);
  90 static bool fix_scan_expr_walker(Node *node, fix_scan_expr_context *context);
  91 static void set_join_references(PlannerGlobal *glob, Join *join, int rtoffset);
  92 static void set_upper_references(PlannerGlobal *glob, Plan *plan, int rtoffset);
  93 static void set_dummy_tlist_references(Plan *plan, int rtoffset);
  94 static indexed_tlist *build_tlist_index(List *tlist);
  95 static Var *search_indexed_tlist_for_var(Var *var,
  96                                                          indexed_tlist *itlist,
  97                                                          Index newvarno,
  98                                                          int rtoffset);
  99 static Var *search_indexed_tlist_for_non_var(Node *node,
 100                                                                  indexed_tlist *itlist,
 101                                                                  Index newvarno);
 102 static Var *search_indexed_tlist_for_sortgroupref(Node *node,
 103                                                                           Index sortgroupref,
 104                                                                           indexed_tlist *itlist,
 105                                                                           Index newvarno);
 106 static List *fix_join_expr(PlannerGlobal *glob,
 107                           List *clauses,
 108                           indexed_tlist *outer_itlist,
 109                           indexed_tlist *inner_itlist,
 110                           Index acceptable_rel, int rtoffset);
 111 static Node *fix_join_expr_mutator(Node *node,
 112                                           fix_join_expr_context *context);
 113 static Node *fix_upper_expr(PlannerGlobal *glob,
 114                            Node *node,
 115                            indexed_tlist *subplan_itlist,
 116                            int rtoffset);
 117 static Node *fix_upper_expr_mutator(Node *node,
 118                                            fix_upper_expr_context *context);
 119 static bool fix_opfuncids_walker(Node *node, void *context);
 120 static bool extract_query_dependencies_walker(Node *node,
 121                                                                   PlannerGlobal *context);
 122
 123
 124 /*****************************************************************************
 125  *
 126  *              SUBPLAN REFERENCES
 127  *
 128  *****************************************************************************/
 129
 130 /*
 131  * set_plan_references
 132  *
 133  * This is the final processing pass of the planner/optimizer.  The plan
 134  * tree is complete; we just have to adjust some representational details
 135  * for the convenience of the executor:
 136  *
 137  * 1. We flatten the various subquery rangetables into a single list, and
 138  * zero out RangeTblEntry fields that are not useful to the executor.
 139  *
 140  * 2. We adjust Vars in scan nodes to be consistent with the flat rangetable.
 141  *
 142  * 3. We adjust Vars in upper plan nodes to refer to the outputs of their
 143  * subplans.
 144  *
 145  * 4. We compute regproc OIDs for operators (ie, we look up the function
 146  * that implements each op).
 147  *
 148  * 5. We create lists of specific objects that the plan depends on.
 149  * This will be used by plancache.c to drive invalidation of cached plans.
 150  * Relation dependencies are represented by OIDs, and everything else by
 151  * PlanInvalItems (this distinction is motivated by the shared-inval APIs).
 152  * Currently, relations and user-defined functions are the only types of
 153  * objects that are explicitly tracked this way.
 154  *
 155  * We also perform one final optimization step, which is to delete
 156  * SubqueryScan plan nodes that aren't doing anything useful (ie, have
 157  * no qual and a no-op targetlist).  The reason for doing this last is that
 158  * it can't readily be done before set_plan_references, because it would
 159  * break set_upper_references: the Vars in the subquery's top tlist
 160  * wouldn't match up with the Vars in the outer plan tree.  The SubqueryScan
 161  * serves a necessary function as a buffer between outer query and subquery
 162  * variable numbering ... but after we've flattened the rangetable this is
 163  * no longer a problem, since then there's only one rtindex namespace.
 164  *
 165  * set_plan_references recursively traverses the whole plan tree.
 166  *
 167  * Inputs:
 168  *      glob: global data for planner run
 169  *      plan: the topmost node of the plan
 170  *      rtable: the rangetable for the current subquery
 171  *      rowmarks: the PlanRowMark list for the current subquery
 172  *
 173  * The return value is normally the same Plan node passed in, but can be
 174  * different when the passed-in Plan is a SubqueryScan we decide isn't needed.
 175  *
 176  * The flattened rangetable entries are appended to glob->finalrtable.
 177  * Also, rowmarks entries are appended to glob->finalrowmarks, and the
 178  * RT indexes of ModifyTable result relations to glob->resultRelations.
 179  * Plan dependencies are appended to glob->relationOids (for relations)
 180  * and glob->invalItems (for everything else).
 181  *
 182  * Notice that we modify Plan nodes in-place, but use expression_tree_mutator
 183  * to process targetlist and qual expressions.  We can assume that the Plan
 184  * nodes were just built by the planner and are not multiply referenced, but
 185  * it's not so safe to assume that for expression tree nodes.
 186  */
 187 Plan *
 188 set_plan_references(PlannerGlobal *glob, Plan *plan,
 189                                         List *rtable, List *rowmarks)
 190 {
 191         int                     rtoffset = list_length(glob->finalrtable);
 192         ListCell   *lc;
 193
 194         /*
 195          * In the flat rangetable, we zero out substructure pointers that are not
 196          * needed by the executor; this reduces the storage space and copying cost
 197          * for cached plans.  We keep only the alias and eref Alias fields, which
 198          * are needed by EXPLAIN, and the selectedCols and modifiedCols bitmaps,
 199          * which are needed for executor-startup permissions checking and for
 200          * trigger event checking.
 201          */
 202         foreach(lc, rtable)
 203         {
 204                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
 205                 RangeTblEntry *newrte;
 206
 207                 /* flat copy to duplicate all the scalar fields */
 208                 newrte = (RangeTblEntry *) palloc(sizeof(RangeTblEntry));
 209                 memcpy(newrte, rte, sizeof(RangeTblEntry));
 210
 211                 /* zap unneeded sub-structure */
 212                 newrte->subquery = NULL;
 213                 newrte->joinaliasvars = NIL;
 214                 newrte->funcexpr = NULL;
 215                 newrte->funccoltypes = NIL;
 216                 newrte->funccoltypmods = NIL;
 217                 newrte->funccolcollations = NIL;
 218                 newrte->values_lists = NIL;
 219                 newrte->values_collations = NIL;
 220                 newrte->ctecoltypes = NIL;
 221                 newrte->ctecoltypmods = NIL;
 222                 newrte->ctecolcollations = NIL;
 223
 224                 glob->finalrtable = lappend(glob->finalrtable, newrte);
 225
 226                 /*
 227                  * If it's a plain relation RTE, add the table to relationOids.
 228                  *
 229                  * We do this even though the RTE might be unreferenced in the plan
 230                  * tree; this would correspond to cases such as views that were
 231                  * expanded, child tables that were eliminated by constraint
 232                  * exclusion, etc.      Schema invalidation on such a rel must still force
 233                  * rebuilding of the plan.
 234                  *
 235                  * Note we don't bother to avoid duplicate list entries.  We could,
 236                  * but it would probably cost more cycles than it would save.
 237                  */
 238                 if (newrte->rtekind == RTE_RELATION)
 239                         glob->relationOids = lappend_oid(glob->relationOids,
 240                                                                                          newrte->relid);
 241         }
 242
 243         /*
 244          * Adjust RT indexes of PlanRowMarks and add to final rowmarks list
 245          */
 246         foreach(lc, rowmarks)
 247         {
 248                 PlanRowMark *rc = (PlanRowMark *) lfirst(lc);
 249                 PlanRowMark *newrc;
 250
 251                 Assert(IsA(rc, PlanRowMark));
 252
 253                 /* flat copy is enough since all fields are scalars */
 254                 newrc = (PlanRowMark *) palloc(sizeof(PlanRowMark));
 255                 memcpy(newrc, rc, sizeof(PlanRowMark));
 256
 257                 /* adjust indexes ... but *not* the rowmarkId */
 258                 newrc->rti += rtoffset;
 259                 newrc->prti += rtoffset;
 260
 261                 glob->finalrowmarks = lappend(glob->finalrowmarks, newrc);
 262         }
 263
 264         /* Now fix the Plan tree */
 265         return set_plan_refs(glob, plan, rtoffset);
 266 }
 267
 268 /*
 269  * set_plan_refs: recurse through the Plan nodes of a single subquery level
 270  */
 271 static Plan *
 272 set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset)
 273 {
 274         ListCell   *l;
 275
 276         if (plan == NULL)
 277                 return NULL;
 278
 279         /*
 280          * Plan-type-specific fixes
 281          */
 282         switch (nodeTag(plan))
 283         {
 284                 case T_SeqScan:
 285                         {
 286                                 SeqScan    *splan = (SeqScan *) plan;
 287
 288                                 splan->scanrelid += rtoffset;
 289                                 splan->plan.targetlist =
 290                                         fix_scan_list(glob, splan->plan.targetlist, rtoffset);
 291                                 splan->plan.qual =
 292                                         fix_scan_list(glob, splan->plan.qual, rtoffset);
 293                         }
 294                         break;
 295                 case T_IndexScan:
 296                         {
 297                                 IndexScan  *splan = (IndexScan *) plan;
 298
 299                                 splan->scan.scanrelid += rtoffset;
 300                                 splan->scan.plan.targetlist =
 301                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 302                                 splan->scan.plan.qual =
 303                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 304                                 splan->indexqual =
 305                                         fix_scan_list(glob, splan->indexqual, rtoffset);
 306                                 splan->indexqualorig =
 307                                         fix_scan_list(glob, splan->indexqualorig, rtoffset);
 308                                 splan->indexorderby =
 309                                         fix_scan_list(glob, splan->indexorderby, rtoffset);
 310                                 splan->indexorderbyorig =
 311                                         fix_scan_list(glob, splan->indexorderbyorig, rtoffset);
 312                         }
 313                         break;
 314                 case T_BitmapIndexScan:
 315                         {
 316                                 BitmapIndexScan *splan = (BitmapIndexScan *) plan;
 317
 318                                 splan->scan.scanrelid += rtoffset;
 319                                 /* no need to fix targetlist and qual */
 320                                 Assert(splan->scan.plan.targetlist == NIL);
 321                                 Assert(splan->scan.plan.qual == NIL);
 322                                 splan->indexqual =
 323                                         fix_scan_list(glob, splan->indexqual, rtoffset);
 324                                 splan->indexqualorig =
 325                                         fix_scan_list(glob, splan->indexqualorig, rtoffset);
 326                         }
 327                         break;
 328                 case T_BitmapHeapScan:
 329                         {
 330                                 BitmapHeapScan *splan = (BitmapHeapScan *) plan;
 331
 332                                 splan->scan.scanrelid += rtoffset;
 333                                 splan->scan.plan.targetlist =
 334                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 335                                 splan->scan.plan.qual =
 336                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 337                                 splan->bitmapqualorig =
 338                                         fix_scan_list(glob, splan->bitmapqualorig, rtoffset);
 339                         }
 340                         break;
 341                 case T_TidScan:
 342                         {
 343                                 TidScan    *splan = (TidScan *) plan;
 344
 345                                 splan->scan.scanrelid += rtoffset;
 346                                 splan->scan.plan.targetlist =
 347                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 348                                 splan->scan.plan.qual =
 349                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 350                                 splan->tidquals =
 351                                         fix_scan_list(glob, splan->tidquals, rtoffset);
 352                         }
 353                         break;
 354                 case T_SubqueryScan:
 355                         /* Needs special treatment, see comments below */
 356                         return set_subqueryscan_references(glob,
 357                                                                                            (SubqueryScan *) plan,
 358                                                                                            rtoffset);
 359                 case T_FunctionScan:
 360                         {
 361                                 FunctionScan *splan = (FunctionScan *) plan;
 362
 363                                 splan->scan.scanrelid += rtoffset;
 364                                 splan->scan.plan.targetlist =
 365                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 366                                 splan->scan.plan.qual =
 367                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 368                                 splan->funcexpr =
 369                                         fix_scan_expr(glob, splan->funcexpr, rtoffset);
 370                         }
 371                         break;
 372                 case T_ValuesScan:
 373                         {
 374                                 ValuesScan *splan = (ValuesScan *) plan;
 375
 376                                 splan->scan.scanrelid += rtoffset;
 377                                 splan->scan.plan.targetlist =
 378                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 379                                 splan->scan.plan.qual =
 380                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 381                                 splan->values_lists =
 382                                         fix_scan_list(glob, splan->values_lists, rtoffset);
 383                         }
 384                         break;
 385                 case T_CteScan:
 386                         {
 387                                 CteScan    *splan = (CteScan *) plan;
 388
 389                                 splan->scan.scanrelid += rtoffset;
 390                                 splan->scan.plan.targetlist =
 391                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 392                                 splan->scan.plan.qual =
 393                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 394                         }
 395                         break;
 396                 case T_WorkTableScan:
 397                         {
 398                                 WorkTableScan *splan = (WorkTableScan *) plan;
 399
 400                                 splan->scan.scanrelid += rtoffset;
 401                                 splan->scan.plan.targetlist =
 402                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 403                                 splan->scan.plan.qual =
 404                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 405                         }
 406                         break;
 407                 case T_ForeignScan:
 408                         {
 409                                 ForeignScan *splan = (ForeignScan *) plan;
 410
 411                                 splan->scan.scanrelid += rtoffset;
 412                                 splan->scan.plan.targetlist =
 413                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 414                                 splan->scan.plan.qual =
 415                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 416                         }
 417                         break;
 418
 419                 case T_NestLoop:
 420                 case T_MergeJoin:
 421                 case T_HashJoin:
 422                         set_join_references(glob, (Join *) plan, rtoffset);
 423                         break;
 424
 425                 case T_Hash:
 426                 case T_Material:
 427                 case T_Sort:
 428                 case T_Unique:
 429                 case T_SetOp:
 430
 431                         /*
 432                          * These plan types don't actually bother to evaluate their
 433                          * targetlists, because they just return their unmodified input
 434                          * tuples.      Even though the targetlist won't be used by the
 435                          * executor, we fix it up for possible use by EXPLAIN (not to
 436                          * mention ease of debugging --- wrong varnos are very confusing).
 437                          */
 438                         set_dummy_tlist_references(plan, rtoffset);
 439
 440                         /*
 441                          * Since these plan types don't check quals either, we should not
 442                          * find any qual expression attached to them.
 443                          */
 444                         Assert(plan->qual == NIL);
 445                         break;
 446                 case T_LockRows:
 447                         {
 448                                 LockRows   *splan = (LockRows *) plan;
 449
 450                                 /*
 451                                  * Like the plan types above, LockRows doesn't evaluate its
 452                                  * tlist or quals.      But we have to fix up the RT indexes in
 453                                  * its rowmarks.
 454                                  */
 455                                 set_dummy_tlist_references(plan, rtoffset);
 456                                 Assert(splan->plan.qual == NIL);
 457
 458                                 foreach(l, splan->rowMarks)
 459                                 {
 460                                         PlanRowMark *rc = (PlanRowMark *) lfirst(l);
 461
 462                                         rc->rti += rtoffset;
 463                                         rc->prti += rtoffset;
 464                                 }
 465                         }
 466                         break;
 467                 case T_Limit:
 468                         {
 469                                 Limit      *splan = (Limit *) plan;
 470
 471                                 /*
 472                                  * Like the plan types above, Limit doesn't evaluate its tlist
 473                                  * or quals.  It does have live expressions for limit/offset,
 474                                  * however; and those cannot contain subplan variable refs, so
 475                                  * fix_scan_expr works for them.
 476                                  */
 477                                 set_dummy_tlist_references(plan, rtoffset);
 478                                 Assert(splan->plan.qual == NIL);
 479
 480                                 splan->limitOffset =
 481                                         fix_scan_expr(glob, splan->limitOffset, rtoffset);
 482                                 splan->limitCount =
 483                                         fix_scan_expr(glob, splan->limitCount, rtoffset);
 484                         }
 485                         break;
 486                 case T_Agg:
 487                 case T_Group:
 488                         set_upper_references(glob, plan, rtoffset);
 489                         break;
 490                 case T_WindowAgg:
 491                         {
 492                                 WindowAgg  *wplan = (WindowAgg *) plan;
 493
 494                                 set_upper_references(glob, plan, rtoffset);
 495
 496                                 /*
 497                                  * Like Limit node limit/offset expressions, WindowAgg has
 498                                  * frame offset expressions, which cannot contain subplan
 499                                  * variable refs, so fix_scan_expr works for them.
 500                                  */
 501                                 wplan->startOffset =
 502                                         fix_scan_expr(glob, wplan->startOffset, rtoffset);
 503                                 wplan->endOffset =
 504                                         fix_scan_expr(glob, wplan->endOffset, rtoffset);
 505                         }
 506                         break;
 507                 case T_Result:
 508                         {
 509                                 Result     *splan = (Result *) plan;
 510
 511                                 /*
 512                                  * Result may or may not have a subplan; if not, it's more
 513                                  * like a scan node than an upper node.
 514                                  */
 515                                 if (splan->plan.lefttree != NULL)
 516                                         set_upper_references(glob, plan, rtoffset);
 517                                 else
 518                                 {
 519                                         splan->plan.targetlist =
 520                                                 fix_scan_list(glob, splan->plan.targetlist, rtoffset);
 521                                         splan->plan.qual =
 522                                                 fix_scan_list(glob, splan->plan.qual, rtoffset);
 523                                 }
 524                                 /* resconstantqual can't contain any subplan variable refs */
 525                                 splan->resconstantqual =
 526                                         fix_scan_expr(glob, splan->resconstantqual, rtoffset);
 527                         }
 528                         break;
 529                 case T_ModifyTable:
 530                         {
 531                                 ModifyTable *splan = (ModifyTable *) plan;
 532
 533                                 /*
 534                                  * planner.c already called set_returning_clause_references,
 535                                  * so we should not process either the targetlist or the
 536                                  * returningLists.
 537                                  */
 538                                 Assert(splan->plan.qual == NIL);
 539
 540                                 foreach(l, splan->resultRelations)
 541                                 {
 542                                         lfirst_int(l) += rtoffset;
 543                                 }
 544                                 foreach(l, splan->rowMarks)
 545                                 {
 546                                         PlanRowMark *rc = (PlanRowMark *) lfirst(l);
 547
 548                                         rc->rti += rtoffset;
 549                                         rc->prti += rtoffset;
 550                                 }
 551                                 foreach(l, splan->plans)
 552                                 {
 553                                         lfirst(l) = set_plan_refs(glob,
 554                                                                                           (Plan *) lfirst(l),
 555                                                                                           rtoffset);
 556                                 }
 557
 558                                 /*
 559                                  * Append this ModifyTable node's final result relation RT
 560                                  * index(es) to the global list for the plan, and set its
 561                                  * resultRelIndex to reflect their starting position in the
 562                                  * global list.
 563                                  */
 564                                 splan->resultRelIndex = list_length(glob->resultRelations);
 565                                 glob->resultRelations =
 566                                         list_concat(glob->resultRelations,
 567                                                                 list_copy(splan->resultRelations));
 568                         }
 569                         break;
 570                 case T_Append:
 571                         {
 572                                 Append     *splan = (Append *) plan;
 573
 574                                 /*
 575                                  * Append, like Sort et al, doesn't actually evaluate its
 576                                  * targetlist or check quals.
 577                                  */
 578                                 set_dummy_tlist_references(plan, rtoffset);
 579                                 Assert(splan->plan.qual == NIL);
 580                                 foreach(l, splan->appendplans)
 581                                 {
 582                                         lfirst(l) = set_plan_refs(glob,
 583                                                                                           (Plan *) lfirst(l),
 584                                                                                           rtoffset);
 585                                 }
 586                         }
 587                         break;
 588                 case T_MergeAppend:
 589                         {
 590                                 MergeAppend *splan = (MergeAppend *) plan;
 591
 592                                 /*
 593                                  * MergeAppend, like Sort et al, doesn't actually evaluate its
 594                                  * targetlist or check quals.
 595                                  */
 596                                 set_dummy_tlist_references(plan, rtoffset);
 597                                 Assert(splan->plan.qual == NIL);
 598                                 foreach(l, splan->mergeplans)
 599                                 {
 600                                         lfirst(l) = set_plan_refs(glob,
 601                                                                                           (Plan *) lfirst(l),
 602                                                                                           rtoffset);
 603                                 }
 604                         }
 605                         break;
 606                 case T_RecursiveUnion:
 607                         /* This doesn't evaluate targetlist or check quals either */
 608                         set_dummy_tlist_references(plan, rtoffset);
 609                         Assert(plan->qual == NIL);
 610                         break;
 611                 case T_BitmapAnd:
 612                         {
 613                                 BitmapAnd  *splan = (BitmapAnd *) plan;
 614
 615                                 /* BitmapAnd works like Append, but has no tlist */
 616                                 Assert(splan->plan.targetlist == NIL);
 617                                 Assert(splan->plan.qual == NIL);
 618                                 foreach(l, splan->bitmapplans)
 619                                 {
 620                                         lfirst(l) = set_plan_refs(glob,
 621                                                                                           (Plan *) lfirst(l),
 622                                                                                           rtoffset);
 623                                 }
 624                         }
 625                         break;
 626                 case T_BitmapOr:
 627                         {
 628                                 BitmapOr   *splan = (BitmapOr *) plan;
 629
 630                                 /* BitmapOr works like Append, but has no tlist */
 631                                 Assert(splan->plan.targetlist == NIL);
 632                                 Assert(splan->plan.qual == NIL);
 633                                 foreach(l, splan->bitmapplans)
 634                                 {
 635                                         lfirst(l) = set_plan_refs(glob,
 636                                                                                           (Plan *) lfirst(l),
 637                                                                                           rtoffset);
 638                                 }
 639                         }
 640                         break;
 641                 default:
 642                         elog(ERROR, "unrecognized node type: %d",
 643                                  (int) nodeTag(plan));
 644                         break;
 645         }
 646
 647         /*
 648          * Now recurse into child plans, if any
 649          *
 650          * NOTE: it is essential that we recurse into child plans AFTER we set
 651          * subplan references in this plan's tlist and quals.  If we did the
 652          * reference-adjustments bottom-up, then we would fail to match this
 653          * plan's var nodes against the already-modified nodes of the children.
 654          */
 655         plan->lefttree = set_plan_refs(glob, plan->lefttree, rtoffset);
 656         plan->righttree = set_plan_refs(glob, plan->righttree, rtoffset);
 657
 658         return plan;
 659 }
 660
 661 /*
 662  * set_subqueryscan_references
 663  *              Do set_plan_references processing on a SubqueryScan
 664  *
 665  * We try to strip out the SubqueryScan entirely; if we can't, we have
 666  * to do the normal processing on it.
 667  */
 668 static Plan *
 669 set_subqueryscan_references(PlannerGlobal *glob,
 670                                                         SubqueryScan *plan,
 671                                                         int rtoffset)
 672 {
 673         Plan       *result;
 674
 675         /* First, recursively process the subplan */
 676         plan->subplan = set_plan_references(glob, plan->subplan,
 677                                                                                 plan->subrtable, plan->subrowmark);
 678
 679         /* subrtable/subrowmark are no longer needed in the plan tree */
 680         plan->subrtable = NIL;
 681         plan->subrowmark = NIL;
 682
 683         if (trivial_subqueryscan(plan))
 684         {
 685                 /*
 686                  * We can omit the SubqueryScan node and just pull up the subplan.
 687                  */
 688                 ListCell   *lp,
 689                                    *lc;
 690
 691                 result = plan->subplan;
 692
 693                 /* We have to be sure we don't lose any initplans */
 694                 result->initPlan = list_concat(plan->scan.plan.initPlan,
 695                                                                            result->initPlan);
 696
 697                 /*
 698                  * We also have to transfer the SubqueryScan's result-column names
 699                  * into the subplan, else columns sent to client will be improperly
 700                  * labeled if this is the topmost plan level.  Copy the "source
 701                  * column" information too.
 702                  */
 703                 forboth(lp, plan->scan.plan.targetlist, lc, result->targetlist)
 704                 {
 705                         TargetEntry *ptle = (TargetEntry *) lfirst(lp);
 706                         TargetEntry *ctle = (TargetEntry *) lfirst(lc);
 707
 708                         ctle->resname = ptle->resname;
 709                         ctle->resorigtbl = ptle->resorigtbl;
 710                         ctle->resorigcol = ptle->resorigcol;
 711                 }
 712         }
 713         else
 714         {
 715                 /*
 716                  * Keep the SubqueryScan node.  We have to do the processing that
 717                  * set_plan_references would otherwise have done on it.  Notice we do
 718                  * not do set_upper_references() here, because a SubqueryScan will
 719                  * always have been created with correct references to its subplan's
 720                  * outputs to begin with.
 721                  */
 722                 plan->scan.scanrelid += rtoffset;
 723                 plan->scan.plan.targetlist =
 724                         fix_scan_list(glob, plan->scan.plan.targetlist, rtoffset);
 725                 plan->scan.plan.qual =
 726                         fix_scan_list(glob, plan->scan.plan.qual, rtoffset);
 727
 728                 result = (Plan *) plan;
 729         }
 730
 731         return result;
 732 }
 733
 734 /*
 735  * trivial_subqueryscan
 736  *              Detect whether a SubqueryScan can be deleted from the plan tree.
 737  *
 738  * We can delete it if it has no qual to check and the targetlist just
 739  * regurgitates the output of the child plan.
 740  */
 741 static bool
 742 trivial_subqueryscan(SubqueryScan *plan)
 743 {
 744         int                     attrno;
 745         ListCell   *lp,
 746                            *lc;
 747
 748         if (plan->scan.plan.qual != NIL)
 749                 return false;
 750
 751         if (list_length(plan->scan.plan.targetlist) !=
 752                 list_length(plan->subplan->targetlist))
 753                 return false;                   /* tlists not same length */
 754
 755         attrno = 1;
 756         forboth(lp, plan->scan.plan.targetlist, lc, plan->subplan->targetlist)
 757         {
 758                 TargetEntry *ptle = (TargetEntry *) lfirst(lp);
 759                 TargetEntry *ctle = (TargetEntry *) lfirst(lc);
 760
 761                 if (ptle->resjunk != ctle->resjunk)
 762                         return false;           /* tlist doesn't match junk status */
 763
 764                 /*
 765                  * We accept either a Var referencing the corresponding element of the
 766                  * subplan tlist, or a Const equaling the subplan element. See
 767                  * generate_setop_tlist() for motivation.
 768                  */
 769                 if (ptle->expr && IsA(ptle->expr, Var))
 770                 {
 771                         Var                *var = (Var *) ptle->expr;
 772
 773                         Assert(var->varno == plan->scan.scanrelid);
 774                         Assert(var->varlevelsup == 0);
 775                         if (var->varattno != attrno)
 776                                 return false;   /* out of order */
 777                 }
 778                 else if (ptle->expr && IsA(ptle->expr, Const))
 779                 {
 780                         if (!equal(ptle->expr, ctle->expr))
 781                                 return false;
 782                 }
 783                 else
 784                         return false;
 785
 786                 attrno++;
 787         }
 788
 789         return true;
 790 }
 791
 792 /*
 793  * copyVar
 794  *              Copy a Var node.
 795  *
 796  * fix_scan_expr and friends do this enough times that it's worth having
 797  * a bespoke routine instead of using the generic copyObject() function.
 798  */
 799 static inline Var *
 800 copyVar(Var *var)
 801 {
 802         Var                *newvar = (Var *) palloc(sizeof(Var));
 803
 804         *newvar = *var;
 805         return newvar;
 806 }
 807
 808 /*
 809  * fix_expr_common
 810  *              Do generic set_plan_references processing on an expression node
 811  *
 812  * This is code that is common to all variants of expression-fixing.
 813  * We must look up operator opcode info for OpExpr and related nodes,
 814  * add OIDs from regclass Const nodes into glob->relationOids,
 815  * and add catalog TIDs for user-defined functions into glob->invalItems.
 816  *
 817  * We assume it's okay to update opcode info in-place.  So this could possibly
 818  * scribble on the planner's input data structures, but it's OK.
 819  */
 820 static void
 821 fix_expr_common(PlannerGlobal *glob, Node *node)
 822 {
 823         /* We assume callers won't call us on a NULL pointer */
 824         if (IsA(node, Aggref))
 825         {
 826                 record_plan_function_dependency(glob,
 827                                                                                 ((Aggref *) node)->aggfnoid);
 828         }
 829         else if (IsA(node, WindowFunc))
 830         {
 831                 record_plan_function_dependency(glob,
 832                                                                                 ((WindowFunc *) node)->winfnoid);
 833         }
 834         else if (IsA(node, FuncExpr))
 835         {
 836                 record_plan_function_dependency(glob,
 837                                                                                 ((FuncExpr *) node)->funcid);
 838         }
 839         else if (IsA(node, OpExpr))
 840         {
 841                 set_opfuncid((OpExpr *) node);
 842                 record_plan_function_dependency(glob,
 843                                                                                 ((OpExpr *) node)->opfuncid);
 844         }
 845         else if (IsA(node, DistinctExpr))
 846         {
 847                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
 848                 record_plan_function_dependency(glob,
 849                                                                                 ((DistinctExpr *) node)->opfuncid);
 850         }
 851         else if (IsA(node, NullIfExpr))
 852         {
 853                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
 854                 record_plan_function_dependency(glob,
 855                                                                                 ((NullIfExpr *) node)->opfuncid);
 856         }
 857         else if (IsA(node, ScalarArrayOpExpr))
 858         {
 859                 set_sa_opfuncid((ScalarArrayOpExpr *) node);
 860                 record_plan_function_dependency(glob,
 861                                                                          ((ScalarArrayOpExpr *) node)->opfuncid);
 862         }
 863         else if (IsA(node, ArrayCoerceExpr))
 864         {
 865                 if (OidIsValid(((ArrayCoerceExpr *) node)->elemfuncid))
 866                         record_plan_function_dependency(glob,
 867                                                                          ((ArrayCoerceExpr *) node)->elemfuncid);
 868         }
 869         else if (IsA(node, Const))
 870         {
 871                 Const      *con = (Const *) node;
 872
 873                 /* Check for regclass reference */
 874                 if (ISREGCLASSCONST(con))
 875                         glob->relationOids =
 876                                 lappend_oid(glob->relationOids,
 877                                                         DatumGetObjectId(con->constvalue));
 878         }
 879 }
 880
 881 /*
 882  * fix_scan_expr
 883  *              Do set_plan_references processing on a scan-level expression
 884  *
 885  * This consists of incrementing all Vars' varnos by rtoffset,
 886  * looking up operator opcode info for OpExpr and related nodes,
 887  * and adding OIDs from regclass Const nodes into glob->relationOids.
 888  */
 889 static Node *
 890 fix_scan_expr(PlannerGlobal *glob, Node *node, int rtoffset)
 891 {
 892         fix_scan_expr_context context;
 893
 894         context.glob = glob;
 895         context.rtoffset = rtoffset;
 896
 897         if (rtoffset != 0 || glob->lastPHId != 0)
 898         {
 899                 return fix_scan_expr_mutator(node, &context);
 900         }
 901         else
 902         {
 903                 /*
 904                  * If rtoffset == 0, we don't need to change any Vars, and if there
 905                  * are no placeholders anywhere we won't need to remove them.  Then
 906                  * it's OK to just scribble on the input node tree instead of copying
 907                  * (since the only change, filling in any unset opfuncid fields, is
 908                  * harmless).  This saves just enough cycles to be noticeable on
 909                  * trivial queries.
 910                  */
 911                 (void) fix_scan_expr_walker(node, &context);
 912                 return node;
 913         }
 914 }
 915
 916 static Node *
 917 fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
 918 {
 919         if (node == NULL)
 920                 return NULL;
 921         if (IsA(node, Var))
 922         {
 923                 Var                *var = copyVar((Var *) node);
 924
 925                 Assert(var->varlevelsup == 0);
 926
 927                 /*
 928                  * We should not see any Vars marked INNER or OUTER.
 929                  */
 930                 Assert(var->varno != INNER);
 931                 Assert(var->varno != OUTER);
 932                 var->varno += context->rtoffset;
 933                 if (var->varnoold > 0)
 934                         var->varnoold += context->rtoffset;
 935                 return (Node *) var;
 936         }
 937         if (IsA(node, CurrentOfExpr))
 938         {
 939                 CurrentOfExpr *cexpr = (CurrentOfExpr *) copyObject(node);
 940
 941                 Assert(cexpr->cvarno != INNER);
 942                 Assert(cexpr->cvarno != OUTER);
 943                 cexpr->cvarno += context->rtoffset;
 944                 return (Node *) cexpr;
 945         }
 946         if (IsA(node, PlaceHolderVar))
 947         {
 948                 /* At scan level, we should always just evaluate the contained expr */
 949                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
 950
 951                 return fix_scan_expr_mutator((Node *) phv->phexpr, context);
 952         }
 953         fix_expr_common(context->glob, node);
 954         return expression_tree_mutator(node, fix_scan_expr_mutator,
 955                                                                    (void *) context);
 956 }
 957
 958 static bool
 959 fix_scan_expr_walker(Node *node, fix_scan_expr_context *context)
 960 {
 961         if (node == NULL)
 962                 return false;
 963         Assert(!IsA(node, PlaceHolderVar));
 964         fix_expr_common(context->glob, node);
 965         return expression_tree_walker(node, fix_scan_expr_walker,
 966                                                                   (void *) context);
 967 }
 968
 969 /*
 970  * set_join_references
 971  *        Modify the target list and quals of a join node to reference its
 972  *        subplans, by setting the varnos to OUTER or INNER and setting attno
 973  *        values to the result domain number of either the corresponding outer
 974  *        or inner join tuple item.  Also perform opcode lookup for these
 975  *        expressions. and add regclass OIDs to glob->relationOids.
 976  */
 977 static void
 978 set_join_references(PlannerGlobal *glob, Join *join, int rtoffset)
 979 {
 980         Plan       *outer_plan = join->plan.lefttree;
 981         Plan       *inner_plan = join->plan.righttree;
 982         indexed_tlist *outer_itlist;
 983         indexed_tlist *inner_itlist;
 984
 985         outer_itlist = build_tlist_index(outer_plan->targetlist);
 986         inner_itlist = build_tlist_index(inner_plan->targetlist);
 987
 988         /* All join plans have tlist, qual, and joinqual */
 989         join->plan.targetlist = fix_join_expr(glob,
 990                                                                                   join->plan.targetlist,
 991                                                                                   outer_itlist,
 992                                                                                   inner_itlist,
 993                                                                                   (Index) 0,
 994                                                                                   rtoffset);
 995         join->plan.qual = fix_join_expr(glob,
 996                                                                         join->plan.qual,
 997                                                                         outer_itlist,
 998                                                                         inner_itlist,
 999                                                                         (Index) 0,
1000                                                                         rtoffset);
1001         join->joinqual = fix_join_expr(glob,
1002                                                                    join->joinqual,
1003                                                                    outer_itlist,
1004                                                                    inner_itlist,
1005                                                                    (Index) 0,
1006                                                                    rtoffset);
1007
1008         /* Now do join-type-specific stuff */
1009         if (IsA(join, NestLoop))
1010         {
1011                 NestLoop   *nl = (NestLoop *) join;
1012                 ListCell   *lc;
1013
1014                 foreach(lc, nl->nestParams)
1015                 {
1016                         NestLoopParam *nlp = (NestLoopParam *) lfirst(lc);
1017
1018                         nlp->paramval = (Var *) fix_upper_expr(glob,
1019                                                                                                    (Node *) nlp->paramval,
1020                                                                                                    outer_itlist,
1021                                                                                                    rtoffset);
1022                 }
1023         }
1024         else if (IsA(join, MergeJoin))
1025         {
1026                 MergeJoin  *mj = (MergeJoin *) join;
1027
1028                 mj->mergeclauses = fix_join_expr(glob,
1029                                                                                  mj->mergeclauses,
1030                                                                                  outer_itlist,
1031                                                                                  inner_itlist,
1032                                                                                  (Index) 0,
1033                                                                                  rtoffset);
1034         }
1035         else if (IsA(join, HashJoin))
1036         {
1037                 HashJoin   *hj = (HashJoin *) join;
1038
1039                 hj->hashclauses = fix_join_expr(glob,
1040                                                                                 hj->hashclauses,
1041                                                                                 outer_itlist,
1042                                                                                 inner_itlist,
1043                                                                                 (Index) 0,
1044                                                                                 rtoffset);
1045         }
1046
1047         pfree(outer_itlist);
1048         pfree(inner_itlist);
1049 }
1050
1051 /*
1052  * set_upper_references
1053  *        Update the targetlist and quals of an upper-level plan node
1054  *        to refer to the tuples returned by its lefttree subplan.
1055  *        Also perform opcode lookup for these expressions, and
1056  *        add regclass OIDs to glob->relationOids.
1057  *
1058  * This is used for single-input plan types like Agg, Group, Result.
1059  *
1060  * In most cases, we have to match up individual Vars in the tlist and
1061  * qual expressions with elements of the subplan's tlist (which was
1062  * generated by flatten_tlist() from these selfsame expressions, so it
1063  * should have all the required variables).  There is an important exception,
1064  * however: GROUP BY and ORDER BY expressions will have been pushed into the
1065  * subplan tlist unflattened.  If these values are also needed in the output
1066  * then we want to reference the subplan tlist element rather than recomputing
1067  * the expression.
1068  */
1069 static void
1070 set_upper_references(PlannerGlobal *glob, Plan *plan, int rtoffset)
1071 {
1072         Plan       *subplan = plan->lefttree;
1073         indexed_tlist *subplan_itlist;
1074         List       *output_targetlist;
1075         ListCell   *l;
1076
1077         subplan_itlist = build_tlist_index(subplan->targetlist);
1078
1079         output_targetlist = NIL;
1080         foreach(l, plan->targetlist)
1081         {
1082                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1083                 Node       *newexpr;
1084
1085                 /* If it's a non-Var sort/group item, first try to match by sortref */
1086                 if (tle->ressortgroupref != 0 && !IsA(tle->expr, Var))
1087                 {
1088                         newexpr = (Node *)
1089                                 search_indexed_tlist_for_sortgroupref((Node *) tle->expr,
1090                                                                                                           tle->ressortgroupref,
1091                                                                                                           subplan_itlist,
1092                                                                                                           OUTER);
1093                         if (!newexpr)
1094                                 newexpr = fix_upper_expr(glob,
1095                                                                                  (Node *) tle->expr,
1096                                                                                  subplan_itlist,
1097                                                                                  rtoffset);
1098                 }
1099                 else
1100                         newexpr = fix_upper_expr(glob,
1101                                                                          (Node *) tle->expr,
1102                                                                          subplan_itlist,
1103                                                                          rtoffset);
1104                 tle = flatCopyTargetEntry(tle);
1105                 tle->expr = (Expr *) newexpr;
1106                 output_targetlist = lappend(output_targetlist, tle);
1107         }
1108         plan->targetlist = output_targetlist;
1109
1110         plan->qual = (List *)
1111                 fix_upper_expr(glob,
1112                                            (Node *) plan->qual,
1113                                            subplan_itlist,
1114                                            rtoffset);
1115
1116         pfree(subplan_itlist);
1117 }
1118
1119 /*
1120  * set_dummy_tlist_references
1121  *        Replace the targetlist of an upper-level plan node with a simple
1122  *        list of OUTER references to its child.
1123  *
1124  * This is used for plan types like Sort and Append that don't evaluate
1125  * their targetlists.  Although the executor doesn't care at all what's in
1126  * the tlist, EXPLAIN needs it to be realistic.
1127  *
1128  * Note: we could almost use set_upper_references() here, but it fails for
1129  * Append for lack of a lefttree subplan.  Single-purpose code is faster
1130  * anyway.
1131  */
1132 static void
1133 set_dummy_tlist_references(Plan *plan, int rtoffset)
1134 {
1135         List       *output_targetlist;
1136         ListCell   *l;
1137
1138         output_targetlist = NIL;
1139         foreach(l, plan->targetlist)
1140         {
1141                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1142                 Var                *oldvar = (Var *) tle->expr;
1143                 Var                *newvar;
1144
1145                 newvar = makeVar(OUTER,
1146                                                  tle->resno,
1147                                                  exprType((Node *) oldvar),
1148                                                  exprTypmod((Node *) oldvar),
1149                                                  exprCollation((Node *) oldvar),
1150                                                  0);
1151                 if (IsA(oldvar, Var))
1152                 {
1153                         newvar->varnoold = oldvar->varno + rtoffset;
1154                         newvar->varoattno = oldvar->varattno;
1155                 }
1156                 else
1157                 {
1158                         newvar->varnoold = 0;           /* wasn't ever a plain Var */
1159                         newvar->varoattno = 0;
1160                 }
1161
1162                 tle = flatCopyTargetEntry(tle);
1163                 tle->expr = (Expr *) newvar;
1164                 output_targetlist = lappend(output_targetlist, tle);
1165         }
1166         plan->targetlist = output_targetlist;
1167
1168         /* We don't touch plan->qual here */
1169 }
1170
1171
1172 /*
1173  * build_tlist_index --- build an index data structure for a child tlist
1174  *
1175  * In most cases, subplan tlists will be "flat" tlists with only Vars,
1176  * so we try to optimize that case by extracting information about Vars
1177  * in advance.  Matching a parent tlist to a child is still an O(N^2)
1178  * operation, but at least with a much smaller constant factor than plain
1179  * tlist_member() searches.
1180  *
1181  * The result of this function is an indexed_tlist struct to pass to
1182  * search_indexed_tlist_for_var() or search_indexed_tlist_for_non_var().
1183  * When done, the indexed_tlist may be freed with a single pfree().
1184  */
1185 static indexed_tlist *
1186 build_tlist_index(List *tlist)
1187 {
1188         indexed_tlist *itlist;
1189         tlist_vinfo *vinfo;
1190         ListCell   *l;
1191
1192         /* Create data structure with enough slots for all tlist entries */
1193         itlist = (indexed_tlist *)
1194                 palloc(offsetof(indexed_tlist, vars) +
1195                            list_length(tlist) * sizeof(tlist_vinfo));
1196
1197         itlist->tlist = tlist;
1198         itlist->has_ph_vars = false;
1199         itlist->has_non_vars = false;
1200
1201         /* Find the Vars and fill in the index array */
1202         vinfo = itlist->vars;
1203         foreach(l, tlist)
1204         {
1205                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1206
1207                 if (tle->expr && IsA(tle->expr, Var))
1208                 {
1209                         Var                *var = (Var *) tle->expr;
1210
1211                         vinfo->varno = var->varno;
1212                         vinfo->varattno = var->varattno;
1213                         vinfo->resno = tle->resno;
1214                         vinfo++;
1215                 }
1216                 else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
1217                         itlist->has_ph_vars = true;
1218                 else
1219                         itlist->has_non_vars = true;
1220         }
1221
1222         itlist->num_vars = (vinfo - itlist->vars);
1223
1224         return itlist;
1225 }
1226
1227 /*
1228  * build_tlist_index_other_vars --- build a restricted tlist index
1229  *
1230  * This is like build_tlist_index, but we only index tlist entries that
1231  * are Vars belonging to some rel other than the one specified.  We will set
1232  * has_ph_vars (allowing PlaceHolderVars to be matched), but not has_non_vars
1233  * (so nothing other than Vars and PlaceHolderVars can be matched).
1234  */
1235 static indexed_tlist *
1236 build_tlist_index_other_vars(List *tlist, Index ignore_rel)
1237 {
1238         indexed_tlist *itlist;
1239         tlist_vinfo *vinfo;
1240         ListCell   *l;
1241
1242         /* Create data structure with enough slots for all tlist entries */
1243         itlist = (indexed_tlist *)
1244                 palloc(offsetof(indexed_tlist, vars) +
1245                            list_length(tlist) * sizeof(tlist_vinfo));
1246
1247         itlist->tlist = tlist;
1248         itlist->has_ph_vars = false;
1249         itlist->has_non_vars = false;
1250
1251         /* Find the desired Vars and fill in the index array */
1252         vinfo = itlist->vars;
1253         foreach(l, tlist)
1254         {
1255                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1256
1257                 if (tle->expr && IsA(tle->expr, Var))
1258                 {
1259                         Var                *var = (Var *) tle->expr;
1260
1261                         if (var->varno != ignore_rel)
1262                         {
1263                                 vinfo->varno = var->varno;
1264                                 vinfo->varattno = var->varattno;
1265                                 vinfo->resno = tle->resno;
1266                                 vinfo++;
1267                         }
1268                 }
1269                 else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
1270                         itlist->has_ph_vars = true;
1271         }
1272
1273         itlist->num_vars = (vinfo - itlist->vars);
1274
1275         return itlist;
1276 }
1277
1278 /*
1279  * search_indexed_tlist_for_var --- find a Var in an indexed tlist
1280  *
1281  * If a match is found, return a copy of the given Var with suitably
1282  * modified varno/varattno (to wit, newvarno and the resno of the TLE entry).
1283  * Also ensure that varnoold is incremented by rtoffset.
1284  * If no match, return NULL.
1285  */
1286 static Var *
1287 search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
1288                                                          Index newvarno, int rtoffset)
1289 {
1290         Index           varno = var->varno;
1291         AttrNumber      varattno = var->varattno;
1292         tlist_vinfo *vinfo;
1293         int                     i;
1294
1295         vinfo = itlist->vars;
1296         i = itlist->num_vars;
1297         while (i-- > 0)
1298         {
1299                 if (vinfo->varno == varno && vinfo->varattno == varattno)
1300                 {
1301                         /* Found a match */
1302                         Var                *newvar = copyVar(var);
1303
1304                         newvar->varno = newvarno;
1305                         newvar->varattno = vinfo->resno;
1306                         if (newvar->varnoold > 0)
1307                                 newvar->varnoold += rtoffset;
1308                         return newvar;
1309                 }
1310                 vinfo++;
1311         }
1312         return NULL;                            /* no match */
1313 }
1314
1315 /*
1316  * search_indexed_tlist_for_non_var --- find a non-Var in an indexed tlist
1317  *
1318  * If a match is found, return a Var constructed to reference the tlist item.
1319  * If no match, return NULL.
1320  *
1321  * NOTE: it is a waste of time to call this unless itlist->has_ph_vars or
1322  * itlist->has_non_vars
1323  */
1324 static Var *
1325 search_indexed_tlist_for_non_var(Node *node,
1326                                                                  indexed_tlist *itlist, Index newvarno)
1327 {
1328         TargetEntry *tle;
1329
1330         tle = tlist_member(node, itlist->tlist);
1331         if (tle)
1332         {
1333                 /* Found a matching subplan output expression */
1334                 Var                *newvar;
1335
1336                 newvar = makeVarFromTargetEntry(newvarno, tle);
1337                 newvar->varnoold = 0;   /* wasn't ever a plain Var */
1338                 newvar->varoattno = 0;
1339                 return newvar;
1340         }
1341         return NULL;                            /* no match */
1342 }
1343
1344 /*
1345  * search_indexed_tlist_for_sortgroupref --- find a sort/group expression
1346  *              (which is assumed not to be just a Var)
1347  *
1348  * If a match is found, return a Var constructed to reference the tlist item.
1349  * If no match, return NULL.
1350  *
1351  * This is needed to ensure that we select the right subplan TLE in cases
1352  * where there are multiple textually-equal()-but-volatile sort expressions.
1353  * And it's also faster than search_indexed_tlist_for_non_var.
1354  */
1355 static Var *
1356 search_indexed_tlist_for_sortgroupref(Node *node,
1357                                                                           Index sortgroupref,
1358                                                                           indexed_tlist *itlist,
1359                                                                           Index newvarno)
1360 {
1361         ListCell   *lc;
1362
1363         foreach(lc, itlist->tlist)
1364         {
1365                 TargetEntry *tle = (TargetEntry *) lfirst(lc);
1366
1367                 /* The equal() check should be redundant, but let's be paranoid */
1368                 if (tle->ressortgroupref == sortgroupref &&
1369                         equal(node, tle->expr))
1370                 {
1371                         /* Found a matching subplan output expression */
1372                         Var                *newvar;
1373
1374                         newvar = makeVarFromTargetEntry(newvarno, tle);
1375                         newvar->varnoold = 0;           /* wasn't ever a plain Var */
1376                         newvar->varoattno = 0;
1377                         return newvar;
1378                 }
1379         }
1380         return NULL;                            /* no match */
1381 }
1382
1383 /*
1384  * fix_join_expr
1385  *         Create a new set of targetlist entries or join qual clauses by
1386  *         changing the varno/varattno values of variables in the clauses
1387  *         to reference target list values from the outer and inner join
1388  *         relation target lists.  Also perform opcode lookup and add
1389  *         regclass OIDs to glob->relationOids.
1390  *
1391  * This is used in two different scenarios: a normal join clause, where
1392  * all the Vars in the clause *must* be replaced by OUTER or INNER references;
1393  * and a RETURNING clause, which may contain both Vars of the target relation
1394  * and Vars of other relations.  In the latter case we want to replace the
1395  * other-relation Vars by OUTER references, while leaving target Vars alone.
1396  *
1397  * For a normal join, acceptable_rel should be zero so that any failure to
1398  * match a Var will be reported as an error.  For the RETURNING case, pass
1399  * inner_itlist = NULL and acceptable_rel = the ID of the target relation.
1400  *
1401  * 'clauses' is the targetlist or list of join clauses
1402  * 'outer_itlist' is the indexed target list of the outer join relation
1403  * 'inner_itlist' is the indexed target list of the inner join relation,
1404  *              or NULL
1405  * 'acceptable_rel' is either zero or the rangetable index of a relation
1406  *              whose Vars may appear in the clause without provoking an error
1407  * 'rtoffset': how much to increment varnoold by
1408  *
1409  * Returns the new expression tree.  The original clause structure is
1410  * not modified.
1411  */
1412 static List *
1413 fix_join_expr(PlannerGlobal *glob,
1414                           List *clauses,
1415                           indexed_tlist *outer_itlist,
1416                           indexed_tlist *inner_itlist,
1417                           Index acceptable_rel,
1418                           int rtoffset)
1419 {
1420         fix_join_expr_context context;
1421
1422         context.glob = glob;
1423         context.outer_itlist = outer_itlist;
1424         context.inner_itlist = inner_itlist;
1425         context.acceptable_rel = acceptable_rel;
1426         context.rtoffset = rtoffset;
1427         return (List *) fix_join_expr_mutator((Node *) clauses, &context);
1428 }
1429
1430 static Node *
1431 fix_join_expr_mutator(Node *node, fix_join_expr_context *context)
1432 {
1433         Var                *newvar;
1434
1435         if (node == NULL)
1436                 return NULL;
1437         if (IsA(node, Var))
1438         {
1439                 Var                *var = (Var *) node;
1440
1441                 /* First look for the var in the input tlists */
1442                 newvar = search_indexed_tlist_for_var(var,
1443                                                                                           context->outer_itlist,
1444                                                                                           OUTER,
1445                                                                                           context->rtoffset);
1446                 if (newvar)
1447                         return (Node *) newvar;
1448                 if (context->inner_itlist)
1449                 {
1450                         newvar = search_indexed_tlist_for_var(var,
1451                                                                                                   context->inner_itlist,
1452                                                                                                   INNER,
1453                                                                                                   context->rtoffset);
1454                         if (newvar)
1455                                 return (Node *) newvar;
1456                 }
1457
1458                 /* If it's for acceptable_rel, adjust and return it */
1459                 if (var->varno == context->acceptable_rel)
1460                 {
1461                         var = copyVar(var);
1462                         if (var->varnoold > 0)
1463                                 var->varnoold += context->rtoffset;
1464                         return (Node *) var;
1465                 }
1466
1467                 /* No referent found for Var */
1468                 elog(ERROR, "variable not found in subplan target lists");
1469         }
1470         if (IsA(node, PlaceHolderVar))
1471         {
1472                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
1473
1474                 /* See if the PlaceHolderVar has bubbled up from a lower plan node */
1475                 if (context->outer_itlist->has_ph_vars)
1476                 {
1477                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
1478                                                                                                           context->outer_itlist,
1479                                                                                                           OUTER);
1480                         if (newvar)
1481                                 return (Node *) newvar;
1482                 }
1483                 if (context->inner_itlist && context->inner_itlist->has_ph_vars)
1484                 {
1485                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
1486                                                                                                           context->inner_itlist,
1487                                                                                                           INNER);
1488                         if (newvar)
1489                                 return (Node *) newvar;
1490                 }
1491
1492                 /* If not supplied by input plans, evaluate the contained expr */
1493                 return fix_join_expr_mutator((Node *) phv->phexpr, context);
1494         }
1495         /* Try matching more complex expressions too, if tlists have any */
1496         if (context->outer_itlist->has_non_vars)
1497         {
1498                 newvar = search_indexed_tlist_for_non_var(node,
1499                                                                                                   context->outer_itlist,
1500                                                                                                   OUTER);
1501                 if (newvar)
1502                         return (Node *) newvar;
1503         }
1504         if (context->inner_itlist && context->inner_itlist->has_non_vars)
1505         {
1506                 newvar = search_indexed_tlist_for_non_var(node,
1507                                                                                                   context->inner_itlist,
1508                                                                                                   INNER);
1509                 if (newvar)
1510                         return (Node *) newvar;
1511         }
1512         fix_expr_common(context->glob, node);
1513         return expression_tree_mutator(node,
1514                                                                    fix_join_expr_mutator,
1515                                                                    (void *) context);
1516 }
1517
1518 /*
1519  * fix_upper_expr
1520  *              Modifies an expression tree so that all Var nodes reference outputs
1521  *              of a subplan.  Also performs opcode lookup, and adds regclass OIDs to
1522  *              glob->relationOids.
1523  *
1524  * This is used to fix up target and qual expressions of non-join upper-level
1525  * plan nodes.
1526  *
1527  * An error is raised if no matching var can be found in the subplan tlist
1528  * --- so this routine should only be applied to nodes whose subplans'
1529  * targetlists were generated via flatten_tlist() or some such method.
1530  *
1531  * If itlist->has_non_vars is true, then we try to match whole subexpressions
1532  * against elements of the subplan tlist, so that we can avoid recomputing
1533  * expressions that were already computed by the subplan.  (This is relatively
1534  * expensive, so we don't want to try it in the common case where the
1535  * subplan tlist is just a flattened list of Vars.)
1536  *
1537  * 'node': the tree to be fixed (a target item or qual)
1538  * 'subplan_itlist': indexed target list for subplan
1539  * 'rtoffset': how much to increment varnoold by
1540  *
1541  * The resulting tree is a copy of the original in which all Var nodes have
1542  * varno = OUTER, varattno = resno of corresponding subplan target.
1543  * The original tree is not modified.
1544  */
1545 static Node *
1546 fix_upper_expr(PlannerGlobal *glob,
1547                            Node *node,
1548                            indexed_tlist *subplan_itlist,
1549                            int rtoffset)
1550 {
1551         fix_upper_expr_context context;
1552
1553         context.glob = glob;
1554         context.subplan_itlist = subplan_itlist;
1555         context.rtoffset = rtoffset;
1556         return fix_upper_expr_mutator(node, &context);
1557 }
1558
1559 static Node *
1560 fix_upper_expr_mutator(Node *node, fix_upper_expr_context *context)
1561 {
1562         Var                *newvar;
1563
1564         if (node == NULL)
1565                 return NULL;
1566         if (IsA(node, Var))
1567         {
1568                 Var                *var = (Var *) node;
1569
1570                 newvar = search_indexed_tlist_for_var(var,
1571                                                                                           context->subplan_itlist,
1572                                                                                           OUTER,
1573                                                                                           context->rtoffset);
1574                 if (!newvar)
1575                         elog(ERROR, "variable not found in subplan target list");
1576                 return (Node *) newvar;
1577         }
1578         if (IsA(node, PlaceHolderVar))
1579         {
1580                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
1581
1582                 /* See if the PlaceHolderVar has bubbled up from a lower plan node */
1583                 if (context->subplan_itlist->has_ph_vars)
1584                 {
1585                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
1586                                                                                                           context->subplan_itlist,
1587                                                                                                           OUTER);
1588                         if (newvar)
1589                                 return (Node *) newvar;
1590                 }
1591                 /* If not supplied by input plan, evaluate the contained expr */
1592                 return fix_upper_expr_mutator((Node *) phv->phexpr, context);
1593         }
1594         /* Try matching more complex expressions too, if tlist has any */
1595         if (context->subplan_itlist->has_non_vars)
1596         {
1597                 newvar = search_indexed_tlist_for_non_var(node,
1598                                                                                                   context->subplan_itlist,
1599                                                                                                   OUTER);
1600                 if (newvar)
1601                         return (Node *) newvar;
1602         }
1603         fix_expr_common(context->glob, node);
1604         return expression_tree_mutator(node,
1605                                                                    fix_upper_expr_mutator,
1606                                                                    (void *) context);
1607 }
1608
1609 /*
1610  * set_returning_clause_references
1611  *              Perform setrefs.c's work on a RETURNING targetlist
1612  *
1613  * If the query involves more than just the result table, we have to
1614  * adjust any Vars that refer to other tables to reference junk tlist
1615  * entries in the top subplan's targetlist.  Vars referencing the result
1616  * table should be left alone, however (the executor will evaluate them
1617  * using the actual heap tuple, after firing triggers if any).  In the
1618  * adjusted RETURNING list, result-table Vars will still have their
1619  * original varno, but Vars for other rels will have varno OUTER.
1620  *
1621  * We also must perform opcode lookup and add regclass OIDs to
1622  * glob->relationOids.
1623  *
1624  * 'rlist': the RETURNING targetlist to be fixed
1625  * 'topplan': the top subplan node that will be just below the ModifyTable
1626  *              node (note it's not yet passed through set_plan_references)
1627  * 'resultRelation': RT index of the associated result relation
1628  *
1629  * Note: we assume that result relations will have rtoffset zero, that is,
1630  * they are not coming from a subplan.
1631  */
1632 List *
1633 set_returning_clause_references(PlannerGlobal *glob,
1634                                                                 List *rlist,
1635                                                                 Plan *topplan,
1636                                                                 Index resultRelation)
1637 {
1638         indexed_tlist *itlist;
1639
1640         /*
1641          * We can perform the desired Var fixup by abusing the fix_join_expr
1642          * machinery that formerly handled inner indexscan fixup.  We search the
1643          * top plan's targetlist for Vars of non-result relations, and use
1644          * fix_join_expr to convert RETURNING Vars into references to those tlist
1645          * entries, while leaving result-rel Vars as-is.
1646          *
1647          * PlaceHolderVars will also be sought in the targetlist, but no
1648          * more-complex expressions will be.  Note that it is not possible for a
1649          * PlaceHolderVar to refer to the result relation, since the result is
1650          * never below an outer join.  If that case could happen, we'd have to be
1651          * prepared to pick apart the PlaceHolderVar and evaluate its contained
1652          * expression instead.
1653          */
1654         itlist = build_tlist_index_other_vars(topplan->targetlist, resultRelation);
1655
1656         rlist = fix_join_expr(glob,
1657                                                   rlist,
1658                                                   itlist,
1659                                                   NULL,
1660                                                   resultRelation,
1661                                                   0);
1662
1663         pfree(itlist);
1664
1665         return rlist;
1666 }
1667
1668 /*****************************************************************************
1669  *                                      OPERATOR REGPROC LOOKUP
1670  *****************************************************************************/
1671
1672 /*
1673  * fix_opfuncids
1674  *        Calculate opfuncid field from opno for each OpExpr node in given tree.
1675  *        The given tree can be anything expression_tree_walker handles.
1676  *
1677  * The argument is modified in-place.  (This is OK since we'd want the
1678  * same change for any node, even if it gets visited more than once due to
1679  * shared structure.)
1680  */
1681 void
1682 fix_opfuncids(Node *node)
1683 {
1684         /* This tree walk requires no special setup, so away we go... */
1685         fix_opfuncids_walker(node, NULL);
1686 }
1687
1688 static bool
1689 fix_opfuncids_walker(Node *node, void *context)
1690 {
1691         if (node == NULL)
1692                 return false;
1693         if (IsA(node, OpExpr))
1694                 set_opfuncid((OpExpr *) node);
1695         else if (IsA(node, DistinctExpr))
1696                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
1697         else if (IsA(node, NullIfExpr))
1698                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
1699         else if (IsA(node, ScalarArrayOpExpr))
1700                 set_sa_opfuncid((ScalarArrayOpExpr *) node);
1701         return expression_tree_walker(node, fix_opfuncids_walker, context);
1702 }
1703
1704 /*
1705  * set_opfuncid
1706  *              Set the opfuncid (procedure OID) in an OpExpr node,
1707  *              if it hasn't been set already.
1708  *
1709  * Because of struct equivalence, this can also be used for
1710  * DistinctExpr and NullIfExpr nodes.
1711  */
1712 void
1713 set_opfuncid(OpExpr *opexpr)
1714 {
1715         if (opexpr->opfuncid == InvalidOid)
1716                 opexpr->opfuncid = get_opcode(opexpr->opno);
1717 }
1718
1719 /*
1720  * set_sa_opfuncid
1721  *              As above, for ScalarArrayOpExpr nodes.
1722  */
1723 void
1724 set_sa_opfuncid(ScalarArrayOpExpr *opexpr)
1725 {
1726         if (opexpr->opfuncid == InvalidOid)
1727                 opexpr->opfuncid = get_opcode(opexpr->opno);
1728 }
1729
1730 /*****************************************************************************
1731  *                                      QUERY DEPENDENCY MANAGEMENT
1732  *****************************************************************************/
1733
1734 /*
1735  * record_plan_function_dependency
1736  *              Mark the current plan as depending on a particular function.
1737  *
1738  * This is exported so that the function-inlining code can record a
1739  * dependency on a function that it's removed from the plan tree.
1740  */
1741 void
1742 record_plan_function_dependency(PlannerGlobal *glob, Oid funcid)
1743 {
1744         /*
1745          * For performance reasons, we don't bother to track built-in functions;
1746          * we just assume they'll never change (or at least not in ways that'd
1747          * invalidate plans using them).  For this purpose we can consider a
1748          * built-in function to be one with OID less than FirstBootstrapObjectId.
1749          * Note that the OID generator guarantees never to generate such an OID
1750          * after startup, even at OID wraparound.
1751          */
1752         if (funcid >= (Oid) FirstBootstrapObjectId)
1753         {
1754                 HeapTuple       func_tuple;
1755                 PlanInvalItem *inval_item;
1756
1757                 func_tuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(funcid));
1758                 if (!HeapTupleIsValid(func_tuple))
1759                         elog(ERROR, "cache lookup failed for function %u", funcid);
1760
1761                 inval_item = makeNode(PlanInvalItem);
1762
1763                 /*
1764                  * It would work to use any syscache on pg_proc, but plancache.c
1765                  * expects us to use PROCOID.
1766                  */
1767                 inval_item->cacheId = PROCOID;
1768                 inval_item->tupleId = func_tuple->t_self;
1769
1770                 glob->invalItems = lappend(glob->invalItems, inval_item);
1771
1772                 ReleaseSysCache(func_tuple);
1773         }
1774 }
1775
1776 /*
1777  * extract_query_dependencies
1778  *              Given a not-yet-planned query or queries (i.e. a Query node or list
1779  *              of Query nodes), extract dependencies just as set_plan_references
1780  *              would do.
1781  *
1782  * This is needed by plancache.c to handle invalidation of cached unplanned
1783  * queries.
1784  */
1785 void
1786 extract_query_dependencies(Node *query,
1787                                                    List **relationOids,
1788                                                    List **invalItems)
1789 {
1790         PlannerGlobal glob;
1791
1792         /* Make up a dummy PlannerGlobal so we can use this module's machinery */
1793         MemSet(&glob, 0, sizeof(glob));
1794         glob.type = T_PlannerGlobal;
1795         glob.relationOids = NIL;
1796         glob.invalItems = NIL;
1797
1798         (void) extract_query_dependencies_walker(query, &glob);
1799
1800         *relationOids = glob.relationOids;
1801         *invalItems = glob.invalItems;
1802 }
1803
1804 static bool
1805 extract_query_dependencies_walker(Node *node, PlannerGlobal *context)
1806 {
1807         if (node == NULL)
1808                 return false;
1809         Assert(!IsA(node, PlaceHolderVar));
1810         /* Extract function dependencies and check for regclass Consts */
1811         fix_expr_common(context, node);
1812         if (IsA(node, Query))
1813         {
1814                 Query      *query = (Query *) node;
1815                 ListCell   *lc;
1816
1817                 if (query->commandType == CMD_UTILITY)
1818                 {
1819                         /* Ignore utility statements, except EXPLAIN */
1820                         if (IsA(query->utilityStmt, ExplainStmt))
1821                         {
1822                                 query = (Query *) ((ExplainStmt *) query->utilityStmt)->query;
1823                                 Assert(IsA(query, Query));
1824                                 Assert(query->commandType != CMD_UTILITY);
1825                         }
1826                         else
1827                                 return false;
1828                 }
1829
1830                 /* Collect relation OIDs in this Query's rtable */
1831                 foreach(lc, query->rtable)
1832                 {
1833                         RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
1834
1835                         if (rte->rtekind == RTE_RELATION)
1836                                 context->relationOids = lappend_oid(context->relationOids,
1837                                                                                                         rte->relid);
1838                 }
1839
1840                 /* And recurse into the query's subexpressions */
1841                 return query_tree_walker(query, extract_query_dependencies_walker,
1842                                                                  (void *) context, 0);
1843         }
1844         return expression_tree_walker(node, extract_query_dependencies_walker,
1845                                                                   (void *) context);
1846 }