src/backend/executor/execMain.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * execMain.c
   4  *        top level executor interface routines
   5  *
   6  * INTERFACE ROUTINES
   7  *      ExecutorStart()
   8  *      ExecutorRun()
   9  *      ExecutorEnd()
  10  *
  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),
  12  *      ExecutorRun() and ExecutorEnd()
  13  *
  14  *      These three procedures are the external interfaces to the executor.
  15  *      In each case, the query descriptor is required as an argument.
  16  *
  17  *      ExecutorStart() must be called at the beginning of execution of any
  18  *      query plan and ExecutorEnd() should always be called at the end of
  19  *      execution of a plan.
  20  *
  21  *      ExecutorRun accepts direction and count arguments that specify whether
  22  *      the plan is to be executed forwards, backwards, and for how many tuples.
  23  *
  24  * Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
  25  * Portions Copyright (c) 1994, Regents of the University of California
  26  *
  27  *
  28  * IDENTIFICATION
  29  *        $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.235 2004/08/29 04:12:31 momjian Exp $
  30  *
  31  *-------------------------------------------------------------------------
  32  */
  33 #include "postgres.h"
  34
  35 #include "access/heapam.h"
  36 #include "catalog/heap.h"
  37 #include "catalog/namespace.h"
  38 #include "commands/tablecmds.h"
  39 #include "commands/trigger.h"
  40 #include "executor/execdebug.h"
  41 #include "executor/execdefs.h"
  42 #include "miscadmin.h"
  43 #include "optimizer/clauses.h"
  44 #include "optimizer/var.h"
  45 #include "parser/parsetree.h"
  46 #include "utils/acl.h"
  47 #include "utils/guc.h"
  48 #include "utils/lsyscache.h"
  49
  50
  51 typedef struct execRowMark
  52 {
  53         Relation        relation;
  54         Index           rti;
  55         char            resname[32];
  56 } execRowMark;
  57
  58 typedef struct evalPlanQual
  59 {
  60         Index           rti;
  61         EState     *estate;
  62         PlanState  *planstate;
  63         struct evalPlanQual *next;      /* stack of active PlanQual plans */
  64         struct evalPlanQual *free;      /* list of free PlanQual plans */
  65 } evalPlanQual;
  66
  67 /* decls for local routines only used within this module */
  68 static void InitPlan(QueryDesc *queryDesc, bool explainOnly);
  69 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  70                                   Index resultRelationIndex,
  71                                   List *rangeTable,
  72                                   CmdType operation);
  73 static TupleTableSlot *ExecutePlan(EState *estate, PlanState *planstate,
  74                         CmdType operation,
  75                         long numberTuples,
  76                         ScanDirection direction,
  77                         DestReceiver *dest);
  78 static void ExecSelect(TupleTableSlot *slot,
  79                    DestReceiver *dest,
  80                    EState *estate);
  81 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
  82                    EState *estate);
  83 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  84                    EState *estate);
  85 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
  86                    EState *estate);
  87 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  88 static void EndEvalPlanQual(EState *estate);
  89 static void ExecCheckRTEPerms(RangeTblEntry *rte);
  90 static void ExecCheckXactReadOnly(Query *parsetree);
  91 static void EvalPlanQualStart(evalPlanQual *epq, EState *estate,
  92                                   evalPlanQual *priorepq);
  93 static void EvalPlanQualStop(evalPlanQual *epq);
  94
  95 /* end of local decls */
  96
  97
  98 /* ----------------------------------------------------------------
  99  *              ExecutorStart
 100  *
 101  *              This routine must be called at the beginning of any execution of any
 102  *              query plan
 103  *
 104  * Takes a QueryDesc previously created by CreateQueryDesc (it's not real
 105  * clear why we bother to separate the two functions, but...).  The tupDesc
 106  * field of the QueryDesc is filled in to describe the tuples that will be
 107  * returned, and the internal fields (estate and planstate) are set up.
 108  *
 109  * If useCurrentSnapshot is true, run the query with the latest available
 110  * snapshot, instead of the normal QuerySnapshot.  Also, if it's an update
 111  * or delete query, check that the rows to be updated or deleted would be
 112  * visible to the normal QuerySnapshot.  (This is a special-case behavior
 113  * needed for referential integrity updates in serializable transactions.
 114  * We must check all currently-committed rows, but we want to throw a
 115  * can't-serialize error if any rows that would need updates would not be
 116  * visible under the normal serializable snapshot.)
 117  *
 118  * If explainOnly is true, we are not actually intending to run the plan,
 119  * only to set up for EXPLAIN; so skip unwanted side-effects.
 120  *
 121  * NB: the CurrentMemoryContext when this is called will become the parent
 122  * of the per-query context used for this Executor invocation.
 123  * ----------------------------------------------------------------
 124  */
 125 void
 126 ExecutorStart(QueryDesc *queryDesc, bool useCurrentSnapshot, bool explainOnly)
 127 {
 128         EState     *estate;
 129         MemoryContext oldcontext;
 130
 131         /* sanity checks: queryDesc must not be started already */
 132         Assert(queryDesc != NULL);
 133         Assert(queryDesc->estate == NULL);
 134
 135         /*
 136          * If the transaction is read-only, we need to check if any writes are
 137          * planned to non-temporary tables.
 138          */
 139         if (XactReadOnly && !explainOnly)
 140                 ExecCheckXactReadOnly(queryDesc->parsetree);
 141
 142         /*
 143          * Build EState, switch into per-query memory context for startup.
 144          */
 145         estate = CreateExecutorState();
 146         queryDesc->estate = estate;
 147
 148         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 149
 150         /*
 151          * Fill in parameters, if any, from queryDesc
 152          */
 153         estate->es_param_list_info = queryDesc->params;
 154
 155         if (queryDesc->plantree->nParamExec > 0)
 156                 estate->es_param_exec_vals = (ParamExecData *)
 157                         palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 158
 159         estate->es_instrument = queryDesc->doInstrument;
 160
 161         /*
 162          * Make our own private copy of the current query snapshot data.
 163          *
 164          * This "freezes" our idea of which tuples are good and which are not for
 165          * the life of this query, even if it outlives the current command and
 166          * current snapshot.
 167          */
 168         if (useCurrentSnapshot)
 169         {
 170                 /* RI update/delete query --- must use an up-to-date snapshot */
 171                 estate->es_snapshot = CopyCurrentSnapshot();
 172                 /* crosscheck updates/deletes against transaction snapshot */
 173                 estate->es_crosscheck_snapshot = CopyQuerySnapshot();
 174         }
 175         else
 176         {
 177                 /* normal query --- use query snapshot, no crosscheck */
 178                 estate->es_snapshot = CopyQuerySnapshot();
 179                 estate->es_crosscheck_snapshot = SnapshotAny;
 180         }
 181
 182         /*
 183          * Initialize the plan state tree
 184          */
 185         InitPlan(queryDesc, explainOnly);
 186
 187         MemoryContextSwitchTo(oldcontext);
 188 }
 189
 190 /* ----------------------------------------------------------------
 191  *              ExecutorRun
 192  *
 193  *              This is the main routine of the executor module. It accepts
 194  *              the query descriptor from the traffic cop and executes the
 195  *              query plan.
 196  *
 197  *              ExecutorStart must have been called already.
 198  *
 199  *              If direction is NoMovementScanDirection then nothing is done
 200  *              except to start up/shut down the destination.  Otherwise,
 201  *              we retrieve up to 'count' tuples in the specified direction.
 202  *
 203  *              Note: count = 0 is interpreted as no portal limit, i.e., run to
 204  *              completion.
 205  *
 206  * ----------------------------------------------------------------
 207  */
 208 TupleTableSlot *
 209 ExecutorRun(QueryDesc *queryDesc,
 210                         ScanDirection direction, long count)
 211 {
 212         EState     *estate;
 213         CmdType         operation;
 214         DestReceiver *dest;
 215         TupleTableSlot *result;
 216         MemoryContext oldcontext;
 217
 218         /* sanity checks */
 219         Assert(queryDesc != NULL);
 220
 221         estate = queryDesc->estate;
 222
 223         Assert(estate != NULL);
 224
 225         /*
 226          * Switch into per-query memory context
 227          */
 228         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 229
 230         /*
 231          * extract information from the query descriptor and the query
 232          * feature.
 233          */
 234         operation = queryDesc->operation;
 235         dest = queryDesc->dest;
 236
 237         /*
 238          * startup tuple receiver
 239          */
 240         estate->es_processed = 0;
 241         estate->es_lastoid = InvalidOid;
 242
 243         (*dest->rStartup) (dest, operation, queryDesc->tupDesc);
 244
 245         /*
 246          * run plan
 247          */
 248         if (direction == NoMovementScanDirection)
 249                 result = NULL;
 250         else
 251                 result = ExecutePlan(estate,
 252                                                          queryDesc->planstate,
 253                                                          operation,
 254                                                          count,
 255                                                          direction,
 256                                                          dest);
 257
 258         /*
 259          * shutdown receiver
 260          */
 261         (*dest->rShutdown) (dest);
 262
 263         MemoryContextSwitchTo(oldcontext);
 264
 265         return result;
 266 }
 267
 268 /* ----------------------------------------------------------------
 269  *              ExecutorEnd
 270  *
 271  *              This routine must be called at the end of execution of any
 272  *              query plan
 273  * ----------------------------------------------------------------
 274  */
 275 void
 276 ExecutorEnd(QueryDesc *queryDesc)
 277 {
 278         EState     *estate;
 279         MemoryContext oldcontext;
 280
 281         /* sanity checks */
 282         Assert(queryDesc != NULL);
 283
 284         estate = queryDesc->estate;
 285
 286         Assert(estate != NULL);
 287
 288         /*
 289          * Switch into per-query memory context to run ExecEndPlan
 290          */
 291         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 292
 293         ExecEndPlan(queryDesc->planstate, estate);
 294
 295         /*
 296          * Must switch out of context before destroying it
 297          */
 298         MemoryContextSwitchTo(oldcontext);
 299
 300         /*
 301          * Release EState and per-query memory context.  This should release
 302          * everything the executor has allocated.
 303          */
 304         FreeExecutorState(estate);
 305
 306         /* Reset queryDesc fields that no longer point to anything */
 307         queryDesc->tupDesc = NULL;
 308         queryDesc->estate = NULL;
 309         queryDesc->planstate = NULL;
 310 }
 311
 312 /* ----------------------------------------------------------------
 313  *              ExecutorRewind
 314  *
 315  *              This routine may be called on an open queryDesc to rewind it
 316  *              to the start.
 317  * ----------------------------------------------------------------
 318  */
 319 void
 320 ExecutorRewind(QueryDesc *queryDesc)
 321 {
 322         EState     *estate;
 323         MemoryContext oldcontext;
 324
 325         /* sanity checks */
 326         Assert(queryDesc != NULL);
 327
 328         estate = queryDesc->estate;
 329
 330         Assert(estate != NULL);
 331
 332         /* It's probably not sensible to rescan updating queries */
 333         Assert(queryDesc->operation == CMD_SELECT);
 334
 335         /*
 336          * Switch into per-query memory context
 337          */
 338         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 339
 340         /*
 341          * rescan plan
 342          */
 343         ExecReScan(queryDesc->planstate, NULL);
 344
 345         MemoryContextSwitchTo(oldcontext);
 346 }
 347
 348
 349 /*
 350  * ExecCheckRTPerms
 351  *              Check access permissions for all relations listed in a range table.
 352  */
 353 void
 354 ExecCheckRTPerms(List *rangeTable)
 355 {
 356         ListCell   *l;
 357
 358         foreach(l, rangeTable)
 359         {
 360                 RangeTblEntry *rte = lfirst(l);
 361
 362                 ExecCheckRTEPerms(rte);
 363         }
 364 }
 365
 366 /*
 367  * ExecCheckRTEPerms
 368  *              Check access permissions for a single RTE.
 369  */
 370 static void
 371 ExecCheckRTEPerms(RangeTblEntry *rte)
 372 {
 373         AclMode         requiredPerms;
 374         Oid                     relOid;
 375         AclId           userid;
 376
 377         /*
 378          * If it's a subquery, recursively examine its rangetable.
 379          */
 380         if (rte->rtekind == RTE_SUBQUERY)
 381         {
 382                 ExecCheckRTPerms(rte->subquery->rtable);
 383                 return;
 384         }
 385
 386         /*
 387          * Otherwise, only plain-relation RTEs need to be checked here.
 388          * Function RTEs are checked by init_fcache when the function is
 389          * prepared for execution. Join and special RTEs need no checks.
 390          */
 391         if (rte->rtekind != RTE_RELATION)
 392                 return;
 393
 394         /*
 395          * No work if requiredPerms is empty.
 396          */
 397         requiredPerms = rte->requiredPerms;
 398         if (requiredPerms == 0)
 399                 return;
 400
 401         relOid = rte->relid;
 402
 403         /*
 404          * userid to check as: current user unless we have a setuid
 405          * indication.
 406          *
 407          * Note: GetUserId() is presently fast enough that there's no harm in
 408          * calling it separately for each RTE.  If that stops being true, we
 409          * could call it once in ExecCheckRTPerms and pass the userid down
 410          * from there.  But for now, no need for the extra clutter.
 411          */
 412         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 413
 414         /*
 415          * We must have *all* the requiredPerms bits, so use aclmask not
 416          * aclcheck.
 417          */
 418         if (pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL)
 419                 != requiredPerms)
 420                 aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS,
 421                                            get_rel_name(relOid));
 422 }
 423
 424 /*
 425  * Check that the query does not imply any writes to non-temp tables.
 426  */
 427 static void
 428 ExecCheckXactReadOnly(Query *parsetree)
 429 {
 430         ListCell   *l;
 431
 432         /*
 433          * CREATE TABLE AS or SELECT INTO?
 434          *
 435          * XXX should we allow this if the destination is temp?
 436          */
 437         if (parsetree->into != NULL)
 438                 goto fail;
 439
 440         /* Fail if write permissions are requested on any non-temp table */
 441         foreach(l, parsetree->rtable)
 442         {
 443                 RangeTblEntry *rte = lfirst(l);
 444
 445                 if (rte->rtekind == RTE_SUBQUERY)
 446                 {
 447                         ExecCheckXactReadOnly(rte->subquery);
 448                         continue;
 449                 }
 450
 451                 if (rte->rtekind != RTE_RELATION)
 452                         continue;
 453
 454                 if ((rte->requiredPerms & (~ACL_SELECT)) == 0)
 455                         continue;
 456
 457                 if (isTempNamespace(get_rel_namespace(rte->relid)))
 458                         continue;
 459
 460                 goto fail;
 461         }
 462
 463         return;
 464
 465 fail:
 466         ereport(ERROR,
 467                         (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
 468                          errmsg("transaction is read-only")));
 469 }
 470
 471
 472 /* ----------------------------------------------------------------
 473  *              InitPlan
 474  *
 475  *              Initializes the query plan: open files, allocate storage
 476  *              and start up the rule manager
 477  * ----------------------------------------------------------------
 478  */
 479 static void
 480 InitPlan(QueryDesc *queryDesc, bool explainOnly)
 481 {
 482         CmdType         operation = queryDesc->operation;
 483         Query      *parseTree = queryDesc->parsetree;
 484         Plan       *plan = queryDesc->plantree;
 485         EState     *estate = queryDesc->estate;
 486         PlanState  *planstate;
 487         List       *rangeTable;
 488         Relation        intoRelationDesc;
 489         bool            do_select_into;
 490         TupleDesc       tupType;
 491
 492         /*
 493          * Do permissions checks.  It's sufficient to examine the query's top
 494          * rangetable here --- subplan RTEs will be checked during
 495          * ExecInitSubPlan().
 496          */
 497         ExecCheckRTPerms(parseTree->rtable);
 498
 499         /*
 500          * get information from query descriptor
 501          */
 502         rangeTable = parseTree->rtable;
 503
 504         /*
 505          * initialize the node's execution state
 506          */
 507         estate->es_range_table = rangeTable;
 508
 509         /*
 510          * if there is a result relation, initialize result relation stuff
 511          */
 512         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 513         {
 514                 List       *resultRelations = parseTree->resultRelations;
 515                 int                     numResultRelations;
 516                 ResultRelInfo *resultRelInfos;
 517
 518                 if (resultRelations != NIL)
 519                 {
 520                         /*
 521                          * Multiple result relations (due to inheritance)
 522                          * parseTree->resultRelations identifies them all
 523                          */
 524                         ResultRelInfo   *resultRelInfo;
 525                         ListCell                *l;
 526
 527                         numResultRelations = list_length(resultRelations);
 528                         resultRelInfos = (ResultRelInfo *)
 529                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 530                         resultRelInfo = resultRelInfos;
 531                         foreach(l, resultRelations)
 532                         {
 533                                 initResultRelInfo(resultRelInfo,
 534                                                                   lfirst_int(l),
 535                                                                   rangeTable,
 536                                                                   operation);
 537                                 resultRelInfo++;
 538                         }
 539                 }
 540                 else
 541                 {
 542                         /*
 543                          * Single result relation identified by
 544                          * parseTree->resultRelation
 545                          */
 546                         numResultRelations = 1;
 547                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 548                         initResultRelInfo(resultRelInfos,
 549                                                           parseTree->resultRelation,
 550                                                           rangeTable,
 551                                                           operation);
 552                 }
 553
 554                 estate->es_result_relations = resultRelInfos;
 555                 estate->es_num_result_relations = numResultRelations;
 556                 /* Initialize to first or only result rel */
 557                 estate->es_result_relation_info = resultRelInfos;
 558         }
 559         else
 560         {
 561                 /*
 562                  * if no result relation, then set state appropriately
 563                  */
 564                 estate->es_result_relations = NULL;
 565                 estate->es_num_result_relations = 0;
 566                 estate->es_result_relation_info = NULL;
 567         }
 568
 569         /*
 570          * Detect whether we're doing SELECT INTO.  If so, set the force_oids
 571          * flag appropriately so that the plan tree will be initialized with
 572          * the correct tuple descriptors.
 573          */
 574         do_select_into = false;
 575
 576         if (operation == CMD_SELECT && parseTree->into != NULL)
 577         {
 578                 do_select_into = true;
 579                 estate->es_select_into = true;
 580                 estate->es_into_oids = parseTree->intoHasOids;
 581         }
 582
 583         /*
 584          * Have to lock relations selected for update
 585          */
 586         estate->es_rowMark = NIL;
 587         if (parseTree->rowMarks != NIL)
 588         {
 589                 ListCell   *l;
 590
 591                 foreach(l, parseTree->rowMarks)
 592                 {
 593                         Index           rti = lfirst_int(l);
 594                         Oid                     relid = getrelid(rti, rangeTable);
 595                         Relation        relation;
 596                         execRowMark *erm;
 597
 598                         relation = heap_open(relid, RowShareLock);
 599                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 600                         erm->relation = relation;
 601                         erm->rti = rti;
 602                         snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
 603                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 604                 }
 605         }
 606
 607         /*
 608          * initialize the executor "tuple" table.  We need slots for all the
 609          * plan nodes, plus possibly output slots for the junkfilter(s). At
 610          * this point we aren't sure if we need junkfilters, so just add slots
 611          * for them unconditionally.
 612          */
 613         {
 614                 int                     nSlots = ExecCountSlotsNode(plan);
 615
 616                 if (parseTree->resultRelations != NIL)
 617                         nSlots += list_length(parseTree->resultRelations);
 618                 else
 619                         nSlots += 1;
 620                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 621         }
 622
 623         /* mark EvalPlanQual not active */
 624         estate->es_topPlan = plan;
 625         estate->es_evalPlanQual = NULL;
 626         estate->es_evTupleNull = NULL;
 627         estate->es_evTuple = NULL;
 628         estate->es_useEvalPlan = false;
 629
 630         /*
 631          * initialize the private state information for all the nodes in the
 632          * query tree.  This opens files, allocates storage and leaves us
 633          * ready to start processing tuples.
 634          */
 635         planstate = ExecInitNode(plan, estate);
 636
 637         /*
 638          * Get the tuple descriptor describing the type of tuples to return.
 639          * (this is especially important if we are creating a relation with
 640          * "SELECT INTO")
 641          */
 642         tupType = ExecGetResultType(planstate);
 643
 644         /*
 645          * Initialize the junk filter if needed.  SELECT and INSERT queries
 646          * need a filter if there are any junk attrs in the tlist.      INSERT and
 647          * SELECT INTO also need a filter if the plan may return raw disk tuples
 648          * (else heap_insert will be scribbling on the source relation!).
 649          * UPDATE and DELETE always need a filter, since there's always a junk
 650          * 'ctid' attribute present --- no need to look first.
 651          */
 652         {
 653                 bool            junk_filter_needed = false;
 654                 ListCell   *tlist;
 655
 656                 switch (operation)
 657                 {
 658                         case CMD_SELECT:
 659                         case CMD_INSERT:
 660                                 foreach(tlist, plan->targetlist)
 661                                 {
 662                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 663
 664                                         if (tle->resdom->resjunk)
 665                                         {
 666                                                 junk_filter_needed = true;
 667                                                 break;
 668                                         }
 669                                 }
 670                                 if (!junk_filter_needed &&
 671                                         (operation == CMD_INSERT || do_select_into) &&
 672                                         ExecMayReturnRawTuples(planstate))
 673                                         junk_filter_needed = true;
 674                                 break;
 675                         case CMD_UPDATE:
 676                         case CMD_DELETE:
 677                                 junk_filter_needed = true;
 678                                 break;
 679                         default:
 680                                 break;
 681                 }
 682
 683                 if (junk_filter_needed)
 684                 {
 685                         /*
 686                          * If there are multiple result relations, each one needs its
 687                          * own junk filter.  Note this is only possible for
 688                          * UPDATE/DELETE, so we can't be fooled by some needing a
 689                          * filter and some not.
 690                          */
 691                         if (parseTree->resultRelations != NIL)
 692                         {
 693                                 PlanState **appendplans;
 694                                 int                     as_nplans;
 695                                 ResultRelInfo *resultRelInfo;
 696                                 int                     i;
 697
 698                                 /* Top plan had better be an Append here. */
 699                                 Assert(IsA(plan, Append));
 700                                 Assert(((Append *) plan)->isTarget);
 701                                 Assert(IsA(planstate, AppendState));
 702                                 appendplans = ((AppendState *) planstate)->appendplans;
 703                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 704                                 Assert(as_nplans == estate->es_num_result_relations);
 705                                 resultRelInfo = estate->es_result_relations;
 706                                 for (i = 0; i < as_nplans; i++)
 707                                 {
 708                                         PlanState  *subplan = appendplans[i];
 709                                         JunkFilter *j;
 710
 711                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 712                                                                                    ExecGetResultType(subplan),
 713                                                           ExecAllocTableSlot(estate->es_tupleTable));
 714                                         resultRelInfo->ri_junkFilter = j;
 715                                         resultRelInfo++;
 716                                 }
 717
 718                                 /*
 719                                  * Set active junkfilter too; at this point ExecInitAppend
 720                                  * has already selected an active result relation...
 721                                  */
 722                                 estate->es_junkFilter =
 723                                         estate->es_result_relation_info->ri_junkFilter;
 724                         }
 725                         else
 726                         {
 727                                 /* Normal case with just one JunkFilter */
 728                                 JunkFilter *j;
 729
 730                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 731                                                                            tupType,
 732                                                           ExecAllocTableSlot(estate->es_tupleTable));
 733                                 estate->es_junkFilter = j;
 734                                 if (estate->es_result_relation_info)
 735                                         estate->es_result_relation_info->ri_junkFilter = j;
 736
 737                                 /* For SELECT, want to return the cleaned tuple type */
 738                                 if (operation == CMD_SELECT)
 739                                         tupType = j->jf_cleanTupType;
 740                         }
 741                 }
 742                 else
 743                         estate->es_junkFilter = NULL;
 744         }
 745
 746         /*
 747          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 748          * till now so we have the "clean" result tuple type to create the new
 749          * table from.
 750          *
 751          * If EXPLAIN, skip creating the "into" relation.
 752          */
 753         intoRelationDesc = NULL;
 754
 755         if (do_select_into && !explainOnly)
 756         {
 757                 char       *intoName;
 758                 Oid                     namespaceId;
 759                 AclResult       aclresult;
 760                 Oid                     intoRelationId;
 761                 TupleDesc       tupdesc;
 762
 763                 /*
 764                  * find namespace to create in, check permissions
 765                  */
 766                 intoName = parseTree->into->relname;
 767                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 768
 769                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 770                                                                                   ACL_CREATE);
 771                 if (aclresult != ACLCHECK_OK)
 772                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 773                                                    get_namespace_name(namespaceId));
 774
 775                 /*
 776                  * have to copy tupType to get rid of constraints
 777                  */
 778                 tupdesc = CreateTupleDescCopy(tupType);
 779
 780                 intoRelationId = heap_create_with_catalog(intoName,
 781                                                                                                   namespaceId,
 782                                                                                                   InvalidOid,
 783                                                                                                   tupdesc,
 784                                                                                                   RELKIND_RELATION,
 785                                                                                                   false,
 786                                                                                                   true,
 787                                                                                                   0,
 788                                                                                                   ONCOMMIT_NOOP,
 789                                                                                                   allowSystemTableMods);
 790
 791                 FreeTupleDesc(tupdesc);
 792
 793                 /*
 794                  * Advance command counter so that the newly-created relation's
 795                  * catalog tuples will be visible to heap_open.
 796                  */
 797                 CommandCounterIncrement();
 798
 799                 /*
 800                  * If necessary, create a TOAST table for the into relation. Note
 801                  * that AlterTableCreateToastTable ends with
 802                  * CommandCounterIncrement(), so that the TOAST table will be
 803                  * visible for insertion.
 804                  */
 805                 AlterTableCreateToastTable(intoRelationId, true);
 806
 807                 /*
 808                  * And open the constructed table for writing.
 809                  */
 810                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 811         }
 812
 813         estate->es_into_relation_descriptor = intoRelationDesc;
 814
 815         queryDesc->tupDesc = tupType;
 816         queryDesc->planstate = planstate;
 817 }
 818
 819 /*
 820  * Initialize ResultRelInfo data for one result relation
 821  */
 822 static void
 823 initResultRelInfo(ResultRelInfo *resultRelInfo,
 824                                   Index resultRelationIndex,
 825                                   List *rangeTable,
 826                                   CmdType operation)
 827 {
 828         Oid                     resultRelationOid;
 829         Relation        resultRelationDesc;
 830
 831         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 832         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 833
 834         switch (resultRelationDesc->rd_rel->relkind)
 835         {
 836                 case RELKIND_SEQUENCE:
 837                         ereport(ERROR,
 838                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 839                                          errmsg("cannot change sequence \"%s\"",
 840                                                   RelationGetRelationName(resultRelationDesc))));
 841                         break;
 842                 case RELKIND_TOASTVALUE:
 843                         ereport(ERROR,
 844                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 845                                          errmsg("cannot change TOAST relation \"%s\"",
 846                                                   RelationGetRelationName(resultRelationDesc))));
 847                         break;
 848                 case RELKIND_VIEW:
 849                         ereport(ERROR,
 850                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 851                                          errmsg("cannot change view \"%s\"",
 852                                                   RelationGetRelationName(resultRelationDesc))));
 853                         break;
 854         }
 855
 856         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 857         resultRelInfo->type = T_ResultRelInfo;
 858         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 859         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 860         resultRelInfo->ri_NumIndices = 0;
 861         resultRelInfo->ri_IndexRelationDescs = NULL;
 862         resultRelInfo->ri_IndexRelationInfo = NULL;
 863         /* make a copy so as not to depend on relcache info not changing... */
 864         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 865         resultRelInfo->ri_TrigFunctions = NULL;
 866         resultRelInfo->ri_ConstraintExprs = NULL;
 867         resultRelInfo->ri_junkFilter = NULL;
 868
 869         /*
 870          * If there are indices on the result relation, open them and save
 871          * descriptors in the result relation info, so that we can add new
 872          * index entries for the tuples we add/update.  We need not do this
 873          * for a DELETE, however, since deletion doesn't affect indexes.
 874          */
 875         if (resultRelationDesc->rd_rel->relhasindex &&
 876                 operation != CMD_DELETE)
 877                 ExecOpenIndices(resultRelInfo);
 878 }
 879
 880 /*
 881  *              ExecContextForcesOids
 882  *
 883  * This is pretty grotty: when doing INSERT, UPDATE, or SELECT INTO,
 884  * we need to ensure that result tuples have space for an OID iff they are
 885  * going to be stored into a relation that has OIDs.  In other contexts
 886  * we are free to choose whether to leave space for OIDs in result tuples
 887  * (we generally don't want to, but we do if a physical-tlist optimization
 888  * is possible).  This routine checks the plan context and returns TRUE if the
 889  * choice is forced, FALSE if the choice is not forced.  In the TRUE case,
 890  * *hasoids is set to the required value.
 891  *
 892  * One reason this is ugly is that all plan nodes in the plan tree will emit
 893  * tuples with space for an OID, though we really only need the topmost node
 894  * to do so.  However, node types like Sort don't project new tuples but just
 895  * return their inputs, and in those cases the requirement propagates down
 896  * to the input node.  Eventually we might make this code smart enough to
 897  * recognize how far down the requirement really goes, but for now we just
 898  * make all plan nodes do the same thing if the top level forces the choice.
 899  *
 900  * We assume that estate->es_result_relation_info is already set up to
 901  * describe the target relation.  Note that in an UPDATE that spans an
 902  * inheritance tree, some of the target relations may have OIDs and some not.
 903  * We have to make the decisions on a per-relation basis as we initialize
 904  * each of the child plans of the topmost Append plan.
 905  *
 906  * SELECT INTO is even uglier, because we don't have the INTO relation's
 907  * descriptor available when this code runs; we have to look aside at a
 908  * flag set by InitPlan().
 909  */
 910 bool
 911 ExecContextForcesOids(PlanState *planstate, bool *hasoids)
 912 {
 913         if (planstate->state->es_select_into)
 914         {
 915                 *hasoids = planstate->state->es_into_oids;
 916                 return true;
 917         }
 918         else
 919         {
 920                 ResultRelInfo *ri = planstate->state->es_result_relation_info;
 921
 922                 if (ri != NULL)
 923                 {
 924                         Relation        rel = ri->ri_RelationDesc;
 925
 926                         if (rel != NULL)
 927                         {
 928                                 *hasoids = rel->rd_rel->relhasoids;
 929                                 return true;
 930                         }
 931                 }
 932         }
 933
 934         return false;
 935 }
 936
 937 /* ----------------------------------------------------------------
 938  *              ExecEndPlan
 939  *
 940  *              Cleans up the query plan -- closes files and frees up storage
 941  *
 942  * NOTE: we are no longer very worried about freeing storage per se
 943  * in this code; FreeExecutorState should be guaranteed to release all
 944  * memory that needs to be released.  What we are worried about doing
 945  * is closing relations and dropping buffer pins.  Thus, for example,
 946  * tuple tables must be cleared or dropped to ensure pins are released.
 947  * ----------------------------------------------------------------
 948  */
 949 void
 950 ExecEndPlan(PlanState *planstate, EState *estate)
 951 {
 952         ResultRelInfo *resultRelInfo;
 953         int                     i;
 954         ListCell   *l;
 955
 956         /*
 957          * shut down any PlanQual processing we were doing
 958          */
 959         if (estate->es_evalPlanQual != NULL)
 960                 EndEvalPlanQual(estate);
 961
 962         /*
 963          * shut down the node-type-specific query processing
 964          */
 965         ExecEndNode(planstate);
 966
 967         /*
 968          * destroy the executor "tuple" table.
 969          */
 970         ExecDropTupleTable(estate->es_tupleTable, true);
 971         estate->es_tupleTable = NULL;
 972
 973         /*
 974          * close the result relation(s) if any, but hold locks until xact
 975          * commit.
 976          */
 977         resultRelInfo = estate->es_result_relations;
 978         for (i = estate->es_num_result_relations; i > 0; i--)
 979         {
 980                 /* Close indices and then the relation itself */
 981                 ExecCloseIndices(resultRelInfo);
 982                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 983                 resultRelInfo++;
 984         }
 985
 986         /*
 987          * close the "into" relation if necessary, again keeping lock
 988          */
 989         if (estate->es_into_relation_descriptor != NULL)
 990                 heap_close(estate->es_into_relation_descriptor, NoLock);
 991
 992         /*
 993          * close any relations selected FOR UPDATE, again keeping locks
 994          */
 995         foreach(l, estate->es_rowMark)
 996         {
 997                 execRowMark *erm = lfirst(l);
 998
 999                 heap_close(erm->relation, NoLock);
1000         }
1001 }
1002
1003 /* ----------------------------------------------------------------
1004  *              ExecutePlan
1005  *
1006  *              processes the query plan to retrieve 'numberTuples' tuples in the
1007  *              direction specified.
1008  *
1009  *              Retrieves all tuples if numberTuples is 0
1010  *
1011  *              result is either a slot containing the last tuple in the case
1012  *              of a SELECT or NULL otherwise.
1013  *
1014  * Note: the ctid attribute is a 'junk' attribute that is removed before the
1015  * user can see it
1016  * ----------------------------------------------------------------
1017  */
1018 static TupleTableSlot *
1019 ExecutePlan(EState *estate,
1020                         PlanState *planstate,
1021                         CmdType operation,
1022                         long numberTuples,
1023                         ScanDirection direction,
1024                         DestReceiver *dest)
1025 {
1026         JunkFilter *junkfilter;
1027         TupleTableSlot *slot;
1028         ItemPointer tupleid = NULL;
1029         ItemPointerData tuple_ctid;
1030         long            current_tuple_count;
1031         TupleTableSlot *result;
1032
1033         /*
1034          * initialize local variables
1035          */
1036         slot = NULL;
1037         current_tuple_count = 0;
1038         result = NULL;
1039
1040         /*
1041          * Set the direction.
1042          */
1043         estate->es_direction = direction;
1044
1045         /*
1046          * Process BEFORE EACH STATEMENT triggers
1047          */
1048         switch (operation)
1049         {
1050                 case CMD_UPDATE:
1051                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
1052                         break;
1053                 case CMD_DELETE:
1054                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1055                         break;
1056                 case CMD_INSERT:
1057                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1058                         break;
1059                 default:
1060                         /* do nothing */
1061                         break;
1062         }
1063
1064         /*
1065          * Loop until we've processed the proper number of tuples from the
1066          * plan.
1067          */
1068
1069         for (;;)
1070         {
1071                 /* Reset the per-output-tuple exprcontext */
1072                 ResetPerTupleExprContext(estate);
1073
1074                 /*
1075                  * Execute the plan and obtain a tuple
1076                  */
1077 lnext:  ;
1078                 if (estate->es_useEvalPlan)
1079                 {
1080                         slot = EvalPlanQualNext(estate);
1081                         if (TupIsNull(slot))
1082                                 slot = ExecProcNode(planstate);
1083                 }
1084                 else
1085                         slot = ExecProcNode(planstate);
1086
1087                 /*
1088                  * if the tuple is null, then we assume there is nothing more to
1089                  * process so we just return null...
1090                  */
1091                 if (TupIsNull(slot))
1092                 {
1093                         result = NULL;
1094                         break;
1095                 }
1096
1097                 /*
1098                  * if we have a junk filter, then project a new tuple with the
1099                  * junk removed.
1100                  *
1101                  * Store this new "clean" tuple in the junkfilter's resultSlot.
1102                  * (Formerly, we stored it back over the "dirty" tuple, which is
1103                  * WRONG because that tuple slot has the wrong descriptor.)
1104                  *
1105                  * Also, extract all the junk information we need.
1106                  */
1107                 if ((junkfilter = estate->es_junkFilter) != NULL)
1108                 {
1109                         Datum           datum;
1110                         HeapTuple       newTuple;
1111                         bool            isNull;
1112
1113                         /*
1114                          * extract the 'ctid' junk attribute.
1115                          */
1116                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1117                         {
1118                                 if (!ExecGetJunkAttribute(junkfilter,
1119                                                                                   slot,
1120                                                                                   "ctid",
1121                                                                                   &datum,
1122                                                                                   &isNull))
1123                                         elog(ERROR, "could not find junk ctid column");
1124
1125                                 /* shouldn't ever get a null result... */
1126                                 if (isNull)
1127                                         elog(ERROR, "ctid is NULL");
1128
1129                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1130                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1131                                                                                  * ctid!! */
1132                                 tupleid = &tuple_ctid;
1133                         }
1134                         else if (estate->es_rowMark != NIL)
1135                         {
1136                                 ListCell   *l;
1137
1138                 lmark:  ;
1139                                 foreach(l, estate->es_rowMark)
1140                                 {
1141                                         execRowMark *erm = lfirst(l);
1142                                         Buffer          buffer;
1143                                         HeapTupleData tuple;
1144                                         TupleTableSlot *newSlot;
1145                                         int                     test;
1146
1147                                         if (!ExecGetJunkAttribute(junkfilter,
1148                                                                                           slot,
1149                                                                                           erm->resname,
1150                                                                                           &datum,
1151                                                                                           &isNull))
1152                                                 elog(ERROR, "could not find junk \"%s\" column",
1153                                                          erm->resname);
1154
1155                                         /* shouldn't ever get a null result... */
1156                                         if (isNull)
1157                                                 elog(ERROR, "\"%s\" is NULL", erm->resname);
1158
1159                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1160                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1161                                                                                         estate->es_snapshot->curcid);
1162                                         ReleaseBuffer(buffer);
1163                                         switch (test)
1164                                         {
1165                                                 case HeapTupleSelfUpdated:
1166                                                         /* treat it as deleted; do not process */
1167                                                         goto lnext;
1168
1169                                                 case HeapTupleMayBeUpdated:
1170                                                         break;
1171
1172                                                 case HeapTupleUpdated:
1173                                                         if (IsXactIsoLevelSerializable)
1174                                                                 ereport(ERROR,
1175                                                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1176                                                                                  errmsg("could not serialize access due to concurrent update")));
1177                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1178                                                                   (ItemPointer) DatumGetPointer(datum))))
1179                                                         {
1180                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1181                                                                 if (!(TupIsNull(newSlot)))
1182                                                                 {
1183                                                                         slot = newSlot;
1184                                                                         estate->es_useEvalPlan = true;
1185                                                                         goto lmark;
1186                                                                 }
1187                                                         }
1188
1189                                                         /*
1190                                                          * if tuple was deleted or PlanQual failed for
1191                                                          * updated tuple - we must not return this
1192                                                          * tuple!
1193                                                          */
1194                                                         goto lnext;
1195
1196                                                 default:
1197                                                         elog(ERROR, "unrecognized heap_mark4update status: %u",
1198                                                                  test);
1199                                                         return (NULL);
1200                                         }
1201                                 }
1202                         }
1203
1204                         /*
1205                          * Finally create a new "clean" tuple with all junk attributes
1206                          * removed
1207                          */
1208                         newTuple = ExecRemoveJunk(junkfilter, slot);
1209
1210                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1211                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1212                                                                   InvalidBuffer,                /* this tuple has no
1213                                                                                                                  * buffer */
1214                                                                   true);                /* tuple should be pfreed */
1215                 }
1216
1217                 /*
1218                  * now that we have a tuple, do the appropriate thing with it..
1219                  * either return it to the user, add it to a relation someplace,
1220                  * delete it from a relation, or modify some of its attributes.
1221                  */
1222                 switch (operation)
1223                 {
1224                         case CMD_SELECT:
1225                                 ExecSelect(slot,        /* slot containing tuple */
1226                                                    dest,        /* destination's tuple-receiver obj */
1227                                                    estate);
1228                                 result = slot;
1229                                 break;
1230
1231                         case CMD_INSERT:
1232                                 ExecInsert(slot, tupleid, estate);
1233                                 result = NULL;
1234                                 break;
1235
1236                         case CMD_DELETE:
1237                                 ExecDelete(slot, tupleid, estate);
1238                                 result = NULL;
1239                                 break;
1240
1241                         case CMD_UPDATE:
1242                                 ExecUpdate(slot, tupleid, estate);
1243                                 result = NULL;
1244                                 break;
1245
1246                         default:
1247                                 elog(ERROR, "unrecognized operation code: %d",
1248                                          (int) operation);
1249                                 result = NULL;
1250                                 break;
1251                 }
1252
1253                 /*
1254                  * check our tuple count.. if we've processed the proper number
1255                  * then quit, else loop again and process more tuples.  Zero
1256                  * numberTuples means no limit.
1257                  */
1258                 current_tuple_count++;
1259                 if (numberTuples && numberTuples == current_tuple_count)
1260                         break;
1261         }
1262
1263         /*
1264          * Process AFTER EACH STATEMENT triggers
1265          */
1266         switch (operation)
1267         {
1268                 case CMD_UPDATE:
1269                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1270                         break;
1271                 case CMD_DELETE:
1272                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1273                         break;
1274                 case CMD_INSERT:
1275                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1276                         break;
1277                 default:
1278                         /* do nothing */
1279                         break;
1280         }
1281
1282         /*
1283          * here, result is either a slot containing a tuple in the case of a
1284          * SELECT or NULL otherwise.
1285          */
1286         return result;
1287 }
1288
1289 /* ----------------------------------------------------------------
1290  *              ExecSelect
1291  *
1292  *              SELECTs are easy.. we just pass the tuple to the appropriate
1293  *              print function.  The only complexity is when we do a
1294  *              "SELECT INTO", in which case we insert the tuple into
1295  *              the appropriate relation (note: this is a newly created relation
1296  *              so we don't need to worry about indices or locks.)
1297  * ----------------------------------------------------------------
1298  */
1299 static void
1300 ExecSelect(TupleTableSlot *slot,
1301                    DestReceiver *dest,
1302                    EState *estate)
1303 {
1304         HeapTuple       tuple;
1305         TupleDesc       attrtype;
1306
1307         /*
1308          * get the heap tuple out of the tuple table slot
1309          */
1310         tuple = slot->val;
1311         attrtype = slot->ttc_tupleDescriptor;
1312
1313         /*
1314          * insert the tuple into the "into relation"
1315          *
1316          * XXX this probably ought to be replaced by a separate destination
1317          */
1318         if (estate->es_into_relation_descriptor != NULL)
1319         {
1320                 heap_insert(estate->es_into_relation_descriptor, tuple,
1321                                         estate->es_snapshot->curcid);
1322                 IncrAppended();
1323         }
1324
1325         /*
1326          * send the tuple to the destination
1327          */
1328         (*dest->receiveTuple) (tuple, attrtype, dest);
1329         IncrRetrieved();
1330         (estate->es_processed)++;
1331 }
1332
1333 /* ----------------------------------------------------------------
1334  *              ExecInsert
1335  *
1336  *              INSERTs are trickier.. we have to insert the tuple into
1337  *              the base relation and insert appropriate tuples into the
1338  *              index relations.
1339  * ----------------------------------------------------------------
1340  */
1341 static void
1342 ExecInsert(TupleTableSlot *slot,
1343                    ItemPointer tupleid,
1344                    EState *estate)
1345 {
1346         HeapTuple       tuple;
1347         ResultRelInfo *resultRelInfo;
1348         Relation        resultRelationDesc;
1349         int                     numIndices;
1350         Oid                     newId;
1351
1352         /*
1353          * get the heap tuple out of the tuple table slot
1354          */
1355         tuple = slot->val;
1356
1357         /*
1358          * get information on the (current) result relation
1359          */
1360         resultRelInfo = estate->es_result_relation_info;
1361         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1362
1363         /* BEFORE ROW INSERT Triggers */
1364         if (resultRelInfo->ri_TrigDesc &&
1365           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1366         {
1367                 HeapTuple       newtuple;
1368
1369                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1370
1371                 if (newtuple == NULL)   /* "do nothing" */
1372                         return;
1373
1374                 if (newtuple != tuple)  /* modified by Trigger(s) */
1375                 {
1376                         /*
1377                          * Insert modified tuple into tuple table slot, replacing the
1378                          * original.  We assume that it was allocated in per-tuple
1379                          * memory context, and therefore will go away by itself. The
1380                          * tuple table slot should not try to clear it.
1381                          */
1382                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1383                         tuple = newtuple;
1384                 }
1385         }
1386
1387         /*
1388          * Check the constraints of the tuple
1389          */
1390         if (resultRelationDesc->rd_att->constr)
1391                 ExecConstraints(resultRelInfo, slot, estate);
1392
1393         /*
1394          * insert the tuple
1395          */
1396         newId = heap_insert(resultRelationDesc, tuple,
1397                                                 estate->es_snapshot->curcid);
1398
1399         IncrAppended();
1400         (estate->es_processed)++;
1401         estate->es_lastoid = newId;
1402         setLastTid(&(tuple->t_self));
1403
1404         /*
1405          * process indices
1406          *
1407          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1408          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1409          * field.
1410          */
1411         numIndices = resultRelInfo->ri_NumIndices;
1412         if (numIndices > 0)
1413                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1414
1415         /* AFTER ROW INSERT Triggers */
1416         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1417 }
1418
1419 /* ----------------------------------------------------------------
1420  *              ExecDelete
1421  *
1422  *              DELETE is like UPDATE, we delete the tuple and its
1423  *              index tuples.
1424  * ----------------------------------------------------------------
1425  */
1426 static void
1427 ExecDelete(TupleTableSlot *slot,
1428                    ItemPointer tupleid,
1429                    EState *estate)
1430 {
1431         ResultRelInfo *resultRelInfo;
1432         Relation        resultRelationDesc;
1433         ItemPointerData ctid;
1434         int                     result;
1435
1436         /*
1437          * get information on the (current) result relation
1438          */
1439         resultRelInfo = estate->es_result_relation_info;
1440         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1441
1442         /* BEFORE ROW DELETE Triggers */
1443         if (resultRelInfo->ri_TrigDesc &&
1444           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1445         {
1446                 bool            dodelete;
1447
1448                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1449                                                                                 estate->es_snapshot->curcid);
1450
1451                 if (!dodelete)                  /* "do nothing" */
1452                         return;
1453         }
1454
1455         /*
1456          * delete the tuple
1457          */
1458 ldelete:;
1459         result = heap_delete(resultRelationDesc, tupleid,
1460                                                  &ctid,
1461                                                  estate->es_snapshot->curcid,
1462                                                  estate->es_crosscheck_snapshot,
1463                                                  true /* wait for commit */);
1464         switch (result)
1465         {
1466                 case HeapTupleSelfUpdated:
1467                         /* already deleted by self; nothing to do */
1468                         return;
1469
1470                 case HeapTupleMayBeUpdated:
1471                         break;
1472
1473                 case HeapTupleUpdated:
1474                         if (IsXactIsoLevelSerializable)
1475                                 ereport(ERROR,
1476                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1477                                                  errmsg("could not serialize access due to concurrent update")));
1478                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1479                         {
1480                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1481                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1482
1483                                 if (!TupIsNull(epqslot))
1484                                 {
1485                                         *tupleid = ctid;
1486                                         goto ldelete;
1487                                 }
1488                         }
1489                         /* tuple already deleted; nothing to do */
1490                         return;
1491
1492                 default:
1493                         elog(ERROR, "unrecognized heap_delete status: %u", result);
1494                         return;
1495         }
1496
1497         IncrDeleted();
1498         (estate->es_processed)++;
1499
1500         /*
1501          * Note: Normally one would think that we have to delete index tuples
1502          * associated with the heap tuple now..
1503          *
1504          * ... but in POSTGRES, we have no need to do this because the vacuum
1505          * daemon automatically opens an index scan and deletes index tuples
1506          * when it finds deleted heap tuples. -cim 9/27/89
1507          */
1508
1509         /* AFTER ROW DELETE Triggers */
1510         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1511 }
1512
1513 /* ----------------------------------------------------------------
1514  *              ExecUpdate
1515  *
1516  *              note: we can't run UPDATE queries with transactions
1517  *              off because UPDATEs are actually INSERTs and our
1518  *              scan will mistakenly loop forever, updating the tuple
1519  *              it just inserted..      This should be fixed but until it
1520  *              is, we don't want to get stuck in an infinite loop
1521  *              which corrupts your database..
1522  * ----------------------------------------------------------------
1523  */
1524 static void
1525 ExecUpdate(TupleTableSlot *slot,
1526                    ItemPointer tupleid,
1527                    EState *estate)
1528 {
1529         HeapTuple       tuple;
1530         ResultRelInfo *resultRelInfo;
1531         Relation        resultRelationDesc;
1532         ItemPointerData ctid;
1533         int                     result;
1534         int                     numIndices;
1535
1536         /*
1537          * abort the operation if not running transactions
1538          */
1539         if (IsBootstrapProcessingMode())
1540                 elog(ERROR, "cannot UPDATE during bootstrap");
1541
1542         /*
1543          * get the heap tuple out of the tuple table slot
1544          */
1545         tuple = slot->val;
1546
1547         /*
1548          * get information on the (current) result relation
1549          */
1550         resultRelInfo = estate->es_result_relation_info;
1551         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1552
1553         /* BEFORE ROW UPDATE Triggers */
1554         if (resultRelInfo->ri_TrigDesc &&
1555           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1556         {
1557                 HeapTuple       newtuple;
1558
1559                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1560                                                                                 tupleid, tuple,
1561                                                                                 estate->es_snapshot->curcid);
1562
1563                 if (newtuple == NULL)   /* "do nothing" */
1564                         return;
1565
1566                 if (newtuple != tuple)  /* modified by Trigger(s) */
1567                 {
1568                         /*
1569                          * Insert modified tuple into tuple table slot, replacing the
1570                          * original.  We assume that it was allocated in per-tuple
1571                          * memory context, and therefore will go away by itself. The
1572                          * tuple table slot should not try to clear it.
1573                          */
1574                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1575                         tuple = newtuple;
1576                 }
1577         }
1578
1579         /*
1580          * Check the constraints of the tuple
1581          *
1582          * If we generate a new candidate tuple after EvalPlanQual testing, we
1583          * must loop back here and recheck constraints.  (We don't need to
1584          * redo triggers, however.      If there are any BEFORE triggers then
1585          * trigger.c will have done mark4update to lock the correct tuple, so
1586          * there's no need to do them again.)
1587          */
1588 lreplace:;
1589         if (resultRelationDesc->rd_att->constr)
1590                 ExecConstraints(resultRelInfo, slot, estate);
1591
1592         /*
1593          * replace the heap tuple
1594          */
1595         result = heap_update(resultRelationDesc, tupleid, tuple,
1596                                                  &ctid,
1597                                                  estate->es_snapshot->curcid,
1598                                                  estate->es_crosscheck_snapshot,
1599                                                  true /* wait for commit */);
1600         switch (result)
1601         {
1602                 case HeapTupleSelfUpdated:
1603                         /* already deleted by self; nothing to do */
1604                         return;
1605
1606                 case HeapTupleMayBeUpdated:
1607                         break;
1608
1609                 case HeapTupleUpdated:
1610                         if (IsXactIsoLevelSerializable)
1611                                 ereport(ERROR,
1612                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1613                                                  errmsg("could not serialize access due to concurrent update")));
1614                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1615                         {
1616                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1617                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1618
1619                                 if (!TupIsNull(epqslot))
1620                                 {
1621                                         *tupleid = ctid;
1622                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1623                                         slot = ExecStoreTuple(tuple,
1624                                                                         estate->es_junkFilter->jf_resultSlot,
1625                                                                                   InvalidBuffer, true);
1626                                         goto lreplace;
1627                                 }
1628                         }
1629                         /* tuple already deleted; nothing to do */
1630                         return;
1631
1632                 default:
1633                         elog(ERROR, "unrecognized heap_update status: %u", result);
1634                         return;
1635         }
1636
1637         IncrReplaced();
1638         (estate->es_processed)++;
1639
1640         /*
1641          * Note: instead of having to update the old index tuples associated
1642          * with the heap tuple, all we do is form and insert new index tuples.
1643          * This is because UPDATEs are actually DELETEs and INSERTs and index
1644          * tuple deletion is done automagically by the vacuum daemon. All we
1645          * do is insert new index tuples.  -cim 9/27/89
1646          */
1647
1648         /*
1649          * process indices
1650          *
1651          * heap_update updates a tuple in the base relation by invalidating it
1652          * and then inserting a new tuple to the relation.      As a side effect,
1653          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1654          * field.  So we now insert index tuples using the new tupleid stored
1655          * there.
1656          */
1657
1658         numIndices = resultRelInfo->ri_NumIndices;
1659         if (numIndices > 0)
1660                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1661
1662         /* AFTER ROW UPDATE Triggers */
1663         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1664 }
1665
1666 static const char *
1667 ExecRelCheck(ResultRelInfo *resultRelInfo,
1668                          TupleTableSlot *slot, EState *estate)
1669 {
1670         Relation        rel = resultRelInfo->ri_RelationDesc;
1671         int                     ncheck = rel->rd_att->constr->num_check;
1672         ConstrCheck *check = rel->rd_att->constr->check;
1673         ExprContext *econtext;
1674         MemoryContext oldContext;
1675         List       *qual;
1676         int                     i;
1677
1678         /*
1679          * If first time through for this result relation, build expression
1680          * nodetrees for rel's constraint expressions.  Keep them in the
1681          * per-query memory context so they'll survive throughout the query.
1682          */
1683         if (resultRelInfo->ri_ConstraintExprs == NULL)
1684         {
1685                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1686                 resultRelInfo->ri_ConstraintExprs =
1687                         (List **) palloc(ncheck * sizeof(List *));
1688                 for (i = 0; i < ncheck; i++)
1689                 {
1690                         /* ExecQual wants implicit-AND form */
1691                         qual = make_ands_implicit(stringToNode(check[i].ccbin));
1692                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1693                                 ExecPrepareExpr((Expr *) qual, estate);
1694                 }
1695                 MemoryContextSwitchTo(oldContext);
1696         }
1697
1698         /*
1699          * We will use the EState's per-tuple context for evaluating
1700          * constraint expressions (creating it if it's not already there).
1701          */
1702         econtext = GetPerTupleExprContext(estate);
1703
1704         /* Arrange for econtext's scan tuple to be the tuple under test */
1705         econtext->ecxt_scantuple = slot;
1706
1707         /* And evaluate the constraints */
1708         for (i = 0; i < ncheck; i++)
1709         {
1710                 qual = resultRelInfo->ri_ConstraintExprs[i];
1711
1712                 /*
1713                  * NOTE: SQL92 specifies that a NULL result from a constraint
1714                  * expression is not to be treated as a failure.  Therefore, tell
1715                  * ExecQual to return TRUE for NULL.
1716                  */
1717                 if (!ExecQual(qual, econtext, true))
1718                         return check[i].ccname;
1719         }
1720
1721         /* NULL result means no error */
1722         return NULL;
1723 }
1724
1725 void
1726 ExecConstraints(ResultRelInfo *resultRelInfo,
1727                                 TupleTableSlot *slot, EState *estate)
1728 {
1729         Relation        rel = resultRelInfo->ri_RelationDesc;
1730         HeapTuple       tuple = slot->val;
1731         TupleConstr *constr = rel->rd_att->constr;
1732
1733         Assert(constr);
1734
1735         if (constr->has_not_null)
1736         {
1737                 int                     natts = rel->rd_att->natts;
1738                 int                     attrChk;
1739
1740                 for (attrChk = 1; attrChk <= natts; attrChk++)
1741                 {
1742                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1743                                 heap_attisnull(tuple, attrChk))
1744                                 ereport(ERROR,
1745                                                 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1746                                                  errmsg("null value in column \"%s\" violates not-null constraint",
1747                                         NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1748                 }
1749         }
1750
1751         if (constr->num_check > 0)
1752         {
1753                 const char *failed;
1754
1755                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1756                         ereport(ERROR,
1757                                         (errcode(ERRCODE_CHECK_VIOLATION),
1758                                          errmsg("new row for relation \"%s\" violates check constraint \"%s\"",
1759                                                         RelationGetRelationName(rel), failed)));
1760         }
1761 }
1762
1763 /*
1764  * Check a modified tuple to see if we want to process its updated version
1765  * under READ COMMITTED rules.
1766  *
1767  * See backend/executor/README for some info about how this works.
1768  */
1769 TupleTableSlot *
1770 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1771 {
1772         evalPlanQual *epq;
1773         EState     *epqstate;
1774         Relation        relation;
1775         HeapTupleData tuple;
1776         HeapTuple       copyTuple = NULL;
1777         bool            endNode;
1778
1779         Assert(rti != 0);
1780
1781         /*
1782          * find relation containing target tuple
1783          */
1784         if (estate->es_result_relation_info != NULL &&
1785                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1786                 relation = estate->es_result_relation_info->ri_RelationDesc;
1787         else
1788         {
1789                 ListCell   *l;
1790
1791                 relation = NULL;
1792                 foreach(l, estate->es_rowMark)
1793                 {
1794                         if (((execRowMark *) lfirst(l))->rti == rti)
1795                         {
1796                                 relation = ((execRowMark *) lfirst(l))->relation;
1797                                 break;
1798                         }
1799                 }
1800                 if (relation == NULL)
1801                         elog(ERROR, "could not find RowMark for RT index %u", rti);
1802         }
1803
1804         /*
1805          * fetch tid tuple
1806          *
1807          * Loop here to deal with updated or busy tuples
1808          */
1809         tuple.t_self = *tid;
1810         for (;;)
1811         {
1812                 Buffer          buffer;
1813
1814                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1815                 {
1816                         TransactionId xwait = SnapshotDirty->xmax;
1817
1818                         /* xmin should not be dirty... */
1819                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1820                                 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1821
1822                         /*
1823                          * If tuple is being updated by other transaction then we have
1824                          * to wait for its commit/abort.
1825                          */
1826                         if (TransactionIdIsValid(xwait))
1827                         {
1828                                 ReleaseBuffer(buffer);
1829                                 XactLockTableWait(xwait);
1830                                 continue;
1831                         }
1832
1833                         /*
1834                          * We got tuple - now copy it for use by recheck query.
1835                          */
1836                         copyTuple = heap_copytuple(&tuple);
1837                         ReleaseBuffer(buffer);
1838                         break;
1839                 }
1840
1841                 /*
1842                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1843                  * Note that it's possible to get invalid SnapshotDirty->tid if
1844                  * tuple updated by this transaction. Have we to check this ?
1845                  */
1846                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1847                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1848                 {
1849                         /* updated, so look at the updated copy */
1850                         tuple.t_self = SnapshotDirty->tid;
1851                         continue;
1852                 }
1853
1854                 /*
1855                  * Deleted or updated by this transaction; forget it.
1856                  */
1857                 return NULL;
1858         }
1859
1860         /*
1861          * For UPDATE/DELETE we have to return tid of actual row we're
1862          * executing PQ for.
1863          */
1864         *tid = tuple.t_self;
1865
1866         /*
1867          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1868          */
1869         epq = estate->es_evalPlanQual;
1870         endNode = true;
1871
1872         if (epq != NULL && epq->rti == 0)
1873         {
1874                 /* Top PQ stack entry is idle, so re-use it */
1875                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1876                 epq->rti = rti;
1877                 endNode = false;
1878         }
1879
1880         /*
1881          * If this is request for another RTE - Ra, - then we have to check
1882          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1883          * updated again and we have to re-start old execution for Ra and
1884          * forget all what we done after Ra was suspended. Cool? -:))
1885          */
1886         if (epq != NULL && epq->rti != rti &&
1887                 epq->estate->es_evTuple[rti - 1] != NULL)
1888         {
1889                 do
1890                 {
1891                         evalPlanQual *oldepq;
1892
1893                         /* stop execution */
1894                         EvalPlanQualStop(epq);
1895                         /* pop previous PlanQual from the stack */
1896                         oldepq = epq->next;
1897                         Assert(oldepq && oldepq->rti != 0);
1898                         /* push current PQ to freePQ stack */
1899                         oldepq->free = epq;
1900                         epq = oldepq;
1901                         estate->es_evalPlanQual = epq;
1902                 } while (epq->rti != rti);
1903         }
1904
1905         /*
1906          * If we are requested for another RTE then we have to suspend
1907          * execution of current PlanQual and start execution for new one.
1908          */
1909         if (epq == NULL || epq->rti != rti)
1910         {
1911                 /* try to reuse plan used previously */
1912                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1913
1914                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1915                 {
1916                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1917                         newepq->free = NULL;
1918                         newepq->estate = NULL;
1919                         newepq->planstate = NULL;
1920                 }
1921                 else
1922                 {
1923                         /* recycle previously used PlanQual */
1924                         Assert(newepq->estate == NULL);
1925                         epq->free = NULL;
1926                 }
1927                 /* push current PQ to the stack */
1928                 newepq->next = epq;
1929                 epq = newepq;
1930                 estate->es_evalPlanQual = epq;
1931                 epq->rti = rti;
1932                 endNode = false;
1933         }
1934
1935         Assert(epq->rti == rti);
1936
1937         /*
1938          * Ok - we're requested for the same RTE.  Unfortunately we still have
1939          * to end and restart execution of the plan, because ExecReScan
1940          * wouldn't ensure that upper plan nodes would reset themselves.  We
1941          * could make that work if insertion of the target tuple were
1942          * integrated with the Param mechanism somehow, so that the upper plan
1943          * nodes know that their children's outputs have changed.
1944          *
1945          * Note that the stack of free evalPlanQual nodes is quite useless at the
1946          * moment, since it only saves us from pallocing/releasing the
1947          * evalPlanQual nodes themselves.  But it will be useful once we
1948          * implement ReScan instead of end/restart for re-using PlanQual
1949          * nodes.
1950          */
1951         if (endNode)
1952         {
1953                 /* stop execution */
1954                 EvalPlanQualStop(epq);
1955         }
1956
1957         /*
1958          * Initialize new recheck query.
1959          *
1960          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to
1961          * instead copy down changeable state from the top plan (including
1962          * es_result_relation_info, es_junkFilter) and reset locally
1963          * changeable state in the epq (including es_param_exec_vals,
1964          * es_evTupleNull).
1965          */
1966         EvalPlanQualStart(epq, estate, epq->next);
1967
1968         /*
1969          * free old RTE' tuple, if any, and store target tuple where
1970          * relation's scan node will see it
1971          */
1972         epqstate = epq->estate;
1973         if (epqstate->es_evTuple[rti - 1] != NULL)
1974                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1975         epqstate->es_evTuple[rti - 1] = copyTuple;
1976
1977         return EvalPlanQualNext(estate);
1978 }
1979
1980 static TupleTableSlot *
1981 EvalPlanQualNext(EState *estate)
1982 {
1983         evalPlanQual *epq = estate->es_evalPlanQual;
1984         MemoryContext oldcontext;
1985         TupleTableSlot *slot;
1986
1987         Assert(epq->rti != 0);
1988
1989 lpqnext:;
1990         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1991         slot = ExecProcNode(epq->planstate);
1992         MemoryContextSwitchTo(oldcontext);
1993
1994         /*
1995          * No more tuples for this PQ. Continue previous one.
1996          */
1997         if (TupIsNull(slot))
1998         {
1999                 evalPlanQual *oldepq;
2000
2001                 /* stop execution */
2002                 EvalPlanQualStop(epq);
2003                 /* pop old PQ from the stack */
2004                 oldepq = epq->next;
2005                 if (oldepq == NULL)
2006                 {
2007                         /* this is the first (oldest) PQ - mark as free */
2008                         epq->rti = 0;
2009                         estate->es_useEvalPlan = false;
2010                         /* and continue Query execution */
2011                         return (NULL);
2012                 }
2013                 Assert(oldepq->rti != 0);
2014                 /* push current PQ to freePQ stack */
2015                 oldepq->free = epq;
2016                 epq = oldepq;
2017                 estate->es_evalPlanQual = epq;
2018                 goto lpqnext;
2019         }
2020
2021         return (slot);
2022 }
2023
2024 static void
2025 EndEvalPlanQual(EState *estate)
2026 {
2027         evalPlanQual *epq = estate->es_evalPlanQual;
2028
2029         if (epq->rti == 0)                      /* plans already shutdowned */
2030         {
2031                 Assert(epq->next == NULL);
2032                 return;
2033         }
2034
2035         for (;;)
2036         {
2037                 evalPlanQual *oldepq;
2038
2039                 /* stop execution */
2040                 EvalPlanQualStop(epq);
2041                 /* pop old PQ from the stack */
2042                 oldepq = epq->next;
2043                 if (oldepq == NULL)
2044                 {
2045                         /* this is the first (oldest) PQ - mark as free */
2046                         epq->rti = 0;
2047                         estate->es_useEvalPlan = false;
2048                         break;
2049                 }
2050                 Assert(oldepq->rti != 0);
2051                 /* push current PQ to freePQ stack */
2052                 oldepq->free = epq;
2053                 epq = oldepq;
2054                 estate->es_evalPlanQual = epq;
2055         }
2056 }
2057
2058 /*
2059  * Start execution of one level of PlanQual.
2060  *
2061  * This is a cut-down version of ExecutorStart(): we copy some state from
2062  * the top-level estate rather than initializing it fresh.
2063  */
2064 static void
2065 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2066 {
2067         EState     *epqstate;
2068         int                     rtsize;
2069         MemoryContext oldcontext;
2070
2071         rtsize = list_length(estate->es_range_table);
2072
2073         epq->estate = epqstate = CreateExecutorState();
2074
2075         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2076
2077         /*
2078          * The epqstates share the top query's copy of unchanging state such
2079          * as the snapshot, rangetable, result-rel info, and external Param
2080          * info. They need their own copies of local state, including a tuple
2081          * table, es_param_exec_vals, etc.
2082          */
2083         epqstate->es_direction = ForwardScanDirection;
2084         epqstate->es_snapshot = estate->es_snapshot;
2085         epqstate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
2086         epqstate->es_range_table = estate->es_range_table;
2087         epqstate->es_result_relations = estate->es_result_relations;
2088         epqstate->es_num_result_relations = estate->es_num_result_relations;
2089         epqstate->es_result_relation_info = estate->es_result_relation_info;
2090         epqstate->es_junkFilter = estate->es_junkFilter;
2091         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2092         epqstate->es_param_list_info = estate->es_param_list_info;
2093         if (estate->es_topPlan->nParamExec > 0)
2094                 epqstate->es_param_exec_vals = (ParamExecData *)
2095                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2096         epqstate->es_rowMark = estate->es_rowMark;
2097         epqstate->es_instrument = estate->es_instrument;
2098         epqstate->es_select_into = estate->es_select_into;
2099         epqstate->es_into_oids = estate->es_into_oids;
2100         epqstate->es_topPlan = estate->es_topPlan;
2101
2102         /*
2103          * Each epqstate must have its own es_evTupleNull state, but all the
2104          * stack entries share es_evTuple state.  This allows sub-rechecks to
2105          * inherit the value being examined by an outer recheck.
2106          */
2107         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2108         if (priorepq == NULL)
2109                 /* first PQ stack entry */
2110                 epqstate->es_evTuple = (HeapTuple *)
2111                         palloc0(rtsize * sizeof(HeapTuple));
2112         else
2113                 /* later stack entries share the same storage */
2114                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2115
2116         epqstate->es_tupleTable =
2117                 ExecCreateTupleTable(estate->es_tupleTable->size);
2118
2119         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2120
2121         MemoryContextSwitchTo(oldcontext);
2122 }
2123
2124 /*
2125  * End execution of one level of PlanQual.
2126  *
2127  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2128  * of the normal cleanup, but *not* close result relations (which we are
2129  * just sharing from the outer query).
2130  */
2131 static void
2132 EvalPlanQualStop(evalPlanQual *epq)
2133 {
2134         EState     *epqstate = epq->estate;
2135         MemoryContext oldcontext;
2136
2137         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2138
2139         ExecEndNode(epq->planstate);
2140
2141         ExecDropTupleTable(epqstate->es_tupleTable, true);
2142         epqstate->es_tupleTable = NULL;
2143
2144         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2145         {
2146                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2147                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2148         }
2149
2150         MemoryContextSwitchTo(oldcontext);
2151
2152         FreeExecutorState(epqstate);
2153
2154         epq->estate = NULL;
2155         epq->planstate = NULL;
2156 }