granicus.if.org Git - postgresql/blob - 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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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) 1996-2003, 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 1.226 2004/01/10 23:28:44 neilc 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, CmdType operation);
  90 static void ExecCheckXactReadOnly(Query *parsetree, CmdType operation);
  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 (!explainOnly)
 140                 ExecCheckXactReadOnly(queryDesc->parsetree, queryDesc->operation);
 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, CmdType operation)
 355 {
 356         List       *lp;
 357
 358         foreach(lp, rangeTable)
 359         {
 360                 RangeTblEntry *rte = lfirst(lp);
 361
 362                 ExecCheckRTEPerms(rte, operation);
 363         }
 364 }
 365
 366 /*
 367  * ExecCheckRTEPerms
 368  *              Check access permissions for a single RTE.
 369  */
 370 static void
 371 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 372 {
 373         Oid                     relOid;
 374         AclId           userid;
 375         AclResult       aclcheck_result;
 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, operation);
 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         relOid = rte->relid;
 395
 396         /*
 397          * userid to check as: current user unless we have a setuid
 398          * indication.
 399          *
 400          * Note: GetUserId() is presently fast enough that there's no harm in
 401          * calling it separately for each RTE.  If that stops being true, we
 402          * could call it once in ExecCheckRTPerms and pass the userid down
 403          * from there.  But for now, no need for the extra clutter.
 404          */
 405         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 406
 407 #define CHECK(MODE)             pg_class_aclcheck(relOid, userid, MODE)
 408
 409         if (rte->checkForRead)
 410         {
 411                 aclcheck_result = CHECK(ACL_SELECT);
 412                 if (aclcheck_result != ACLCHECK_OK)
 413                         aclcheck_error(aclcheck_result, ACL_KIND_CLASS,
 414                                                    get_rel_name(relOid));
 415         }
 416
 417         if (rte->checkForWrite)
 418         {
 419                 /*
 420                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 421                  * Right now we don't distinguish that from true update as far as
 422                  * permissions checks are concerned.
 423                  */
 424                 switch (operation)
 425                 {
 426                         case CMD_INSERT:
 427                                 aclcheck_result = CHECK(ACL_INSERT);
 428                                 break;
 429                         case CMD_SELECT:
 430                         case CMD_UPDATE:
 431                                 aclcheck_result = CHECK(ACL_UPDATE);
 432                                 break;
 433                         case CMD_DELETE:
 434                                 aclcheck_result = CHECK(ACL_DELETE);
 435                                 break;
 436                         default:
 437                                 elog(ERROR, "unrecognized operation code: %d",
 438                                          (int) operation);
 439                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 440                                 break;
 441                 }
 442                 if (aclcheck_result != ACLCHECK_OK)
 443                         aclcheck_error(aclcheck_result, ACL_KIND_CLASS,
 444                                                    get_rel_name(relOid));
 445         }
 446 }
 447
 448 static void
 449 ExecCheckXactReadOnly(Query *parsetree, CmdType operation)
 450 {
 451         if (!XactReadOnly)
 452                 return;
 453
 454         /* CREATE TABLE AS or SELECT INTO */
 455         if (operation == CMD_SELECT && parsetree->into != NULL)
 456                 goto fail;
 457
 458         if (operation == CMD_DELETE || operation == CMD_INSERT
 459                 || operation == CMD_UPDATE)
 460         {
 461                 List       *lp;
 462
 463                 foreach(lp, parsetree->rtable)
 464                 {
 465                         RangeTblEntry *rte = lfirst(lp);
 466
 467                         if (rte->rtekind != RTE_RELATION)
 468                                 continue;
 469
 470                         if (!rte->checkForWrite)
 471                                 continue;
 472
 473                         if (isTempNamespace(get_rel_namespace(rte->relid)))
 474                                 continue;
 475
 476                         goto fail;
 477                 }
 478         }
 479
 480         return;
 481
 482 fail:
 483         ereport(ERROR,
 484                         (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
 485                          errmsg("transaction is read-only")));
 486 }
 487
 488
 489 /* ----------------------------------------------------------------
 490  *              InitPlan
 491  *
 492  *              Initializes the query plan: open files, allocate storage
 493  *              and start up the rule manager
 494  * ----------------------------------------------------------------
 495  */
 496 static void
 497 InitPlan(QueryDesc *queryDesc, bool explainOnly)
 498 {
 499         CmdType         operation = queryDesc->operation;
 500         Query      *parseTree = queryDesc->parsetree;
 501         Plan       *plan = queryDesc->plantree;
 502         EState     *estate = queryDesc->estate;
 503         PlanState  *planstate;
 504         List       *rangeTable;
 505         Relation        intoRelationDesc;
 506         bool            do_select_into;
 507         TupleDesc       tupType;
 508
 509         /*
 510          * Do permissions checks.  It's sufficient to examine the query's top
 511          * rangetable here --- subplan RTEs will be checked during
 512          * ExecInitSubPlan().
 513          */
 514         ExecCheckRTPerms(parseTree->rtable, operation);
 515
 516         /*
 517          * get information from query descriptor
 518          */
 519         rangeTable = parseTree->rtable;
 520
 521         /*
 522          * initialize the node's execution state
 523          */
 524         estate->es_range_table = rangeTable;
 525
 526         /*
 527          * if there is a result relation, initialize result relation stuff
 528          */
 529         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 530         {
 531                 List       *resultRelations = parseTree->resultRelations;
 532                 int                     numResultRelations;
 533                 ResultRelInfo *resultRelInfos;
 534
 535                 if (resultRelations != NIL)
 536                 {
 537                         /*
 538                          * Multiple result relations (due to inheritance)
 539                          * parseTree->resultRelations identifies them all
 540                          */
 541                         ResultRelInfo *resultRelInfo;
 542
 543                         numResultRelations = length(resultRelations);
 544                         resultRelInfos = (ResultRelInfo *)
 545                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 546                         resultRelInfo = resultRelInfos;
 547                         while (resultRelations != NIL)
 548                         {
 549                                 initResultRelInfo(resultRelInfo,
 550                                                                   lfirsti(resultRelations),
 551                                                                   rangeTable,
 552                                                                   operation);
 553                                 resultRelInfo++;
 554                                 resultRelations = lnext(resultRelations);
 555                         }
 556                 }
 557                 else
 558                 {
 559                         /*
 560                          * Single result relation identified by
 561                          * parseTree->resultRelation
 562                          */
 563                         numResultRelations = 1;
 564                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 565                         initResultRelInfo(resultRelInfos,
 566                                                           parseTree->resultRelation,
 567                                                           rangeTable,
 568                                                           operation);
 569                 }
 570
 571                 estate->es_result_relations = resultRelInfos;
 572                 estate->es_num_result_relations = numResultRelations;
 573                 /* Initialize to first or only result rel */
 574                 estate->es_result_relation_info = resultRelInfos;
 575         }
 576         else
 577         {
 578                 /*
 579                  * if no result relation, then set state appropriately
 580                  */
 581                 estate->es_result_relations = NULL;
 582                 estate->es_num_result_relations = 0;
 583                 estate->es_result_relation_info = NULL;
 584         }
 585
 586         /*
 587          * Detect whether we're doing SELECT INTO.  If so, set the force_oids
 588          * flag appropriately so that the plan tree will be initialized with
 589          * the correct tuple descriptors.
 590          */
 591         do_select_into = false;
 592
 593         if (operation == CMD_SELECT && parseTree->into != NULL)
 594         {
 595                 do_select_into = true;
 596                 estate->es_force_oids = parseTree->intoHasOids;
 597         }
 598
 599         /*
 600          * Have to lock relations selected for update
 601          */
 602         estate->es_rowMark = NIL;
 603         if (parseTree->rowMarks != NIL)
 604         {
 605                 List       *l;
 606
 607                 foreach(l, parseTree->rowMarks)
 608                 {
 609                         Index           rti = lfirsti(l);
 610                         Oid                     relid = getrelid(rti, rangeTable);
 611                         Relation        relation;
 612                         execRowMark *erm;
 613
 614                         relation = heap_open(relid, RowShareLock);
 615                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 616                         erm->relation = relation;
 617                         erm->rti = rti;
 618                         snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
 619                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 620                 }
 621         }
 622
 623         /*
 624          * initialize the executor "tuple" table.  We need slots for all the
 625          * plan nodes, plus possibly output slots for the junkfilter(s). At
 626          * this point we aren't sure if we need junkfilters, so just add slots
 627          * for them unconditionally.
 628          */
 629         {
 630                 int                     nSlots = ExecCountSlotsNode(plan);
 631
 632                 if (parseTree->resultRelations != NIL)
 633                         nSlots += length(parseTree->resultRelations);
 634                 else
 635                         nSlots += 1;
 636                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 637         }
 638
 639         /* mark EvalPlanQual not active */
 640         estate->es_topPlan = plan;
 641         estate->es_evalPlanQual = NULL;
 642         estate->es_evTupleNull = NULL;
 643         estate->es_evTuple = NULL;
 644         estate->es_useEvalPlan = false;
 645
 646         /*
 647          * initialize the private state information for all the nodes in the
 648          * query tree.  This opens files, allocates storage and leaves us
 649          * ready to start processing tuples.
 650          */
 651         planstate = ExecInitNode(plan, estate);
 652
 653         /*
 654          * Get the tuple descriptor describing the type of tuples to return.
 655          * (this is especially important if we are creating a relation with
 656          * "SELECT INTO")
 657          */
 658         tupType = ExecGetResultType(planstate);
 659
 660         /*
 661          * Initialize the junk filter if needed.  SELECT and INSERT queries
 662          * need a filter if there are any junk attrs in the tlist.      INSERT and
 663          * SELECT INTO also need a filter if the top plan node is a scan node
 664          * that's not doing projection (else we'll be scribbling on the scan
 665          * tuple!)      UPDATE and DELETE always need a filter, since there's
 666          * always a junk 'ctid' attribute present --- no need to look first.
 667          */
 668         {
 669                 bool            junk_filter_needed = false;
 670                 List       *tlist;
 671
 672                 switch (operation)
 673                 {
 674                         case CMD_SELECT:
 675                         case CMD_INSERT:
 676                                 foreach(tlist, plan->targetlist)
 677                                 {
 678                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 679
 680                                         if (tle->resdom->resjunk)
 681                                         {
 682                                                 junk_filter_needed = true;
 683                                                 break;
 684                                         }
 685                                 }
 686                                 if (!junk_filter_needed &&
 687                                         (operation == CMD_INSERT || do_select_into))
 688                                 {
 689                                         if (IsA(planstate, SeqScanState) ||
 690                                                 IsA(planstate, IndexScanState) ||
 691                                                 IsA(planstate, TidScanState) ||
 692                                                 IsA(planstate, SubqueryScanState) ||
 693                                                 IsA(planstate, FunctionScanState))
 694                                         {
 695                                                 if (planstate->ps_ProjInfo == NULL)
 696                                                         junk_filter_needed = true;
 697                                         }
 698                                 }
 699                                 break;
 700                         case CMD_UPDATE:
 701                         case CMD_DELETE:
 702                                 junk_filter_needed = true;
 703                                 break;
 704                         default:
 705                                 break;
 706                 }
 707
 708                 if (junk_filter_needed)
 709                 {
 710                         /*
 711                          * If there are multiple result relations, each one needs its
 712                          * own junk filter.  Note this is only possible for
 713                          * UPDATE/DELETE, so we can't be fooled by some needing a
 714                          * filter and some not.
 715                          */
 716                         if (parseTree->resultRelations != NIL)
 717                         {
 718                                 PlanState **appendplans;
 719                                 int                     as_nplans;
 720                                 ResultRelInfo *resultRelInfo;
 721                                 int                     i;
 722
 723                                 /* Top plan had better be an Append here. */
 724                                 Assert(IsA(plan, Append));
 725                                 Assert(((Append *) plan)->isTarget);
 726                                 Assert(IsA(planstate, AppendState));
 727                                 appendplans = ((AppendState *) planstate)->appendplans;
 728                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 729                                 Assert(as_nplans == estate->es_num_result_relations);
 730                                 resultRelInfo = estate->es_result_relations;
 731                                 for (i = 0; i < as_nplans; i++)
 732                                 {
 733                                         PlanState  *subplan = appendplans[i];
 734                                         JunkFilter *j;
 735
 736                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 737                                                                                    ExecGetResultType(subplan),
 738                                                           ExecAllocTableSlot(estate->es_tupleTable));
 739                                         resultRelInfo->ri_junkFilter = j;
 740                                         resultRelInfo++;
 741                                 }
 742
 743                                 /*
 744                                  * Set active junkfilter too; at this point ExecInitAppend
 745                                  * has already selected an active result relation...
 746                                  */
 747                                 estate->es_junkFilter =
 748                                         estate->es_result_relation_info->ri_junkFilter;
 749                         }
 750                         else
 751                         {
 752                                 /* Normal case with just one JunkFilter */
 753                                 JunkFilter *j;
 754
 755                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 756                                                                            tupType,
 757                                                           ExecAllocTableSlot(estate->es_tupleTable));
 758                                 estate->es_junkFilter = j;
 759                                 if (estate->es_result_relation_info)
 760                                         estate->es_result_relation_info->ri_junkFilter = j;
 761
 762                                 /* For SELECT, want to return the cleaned tuple type */
 763                                 if (operation == CMD_SELECT)
 764                                         tupType = j->jf_cleanTupType;
 765                         }
 766                 }
 767                 else
 768                         estate->es_junkFilter = NULL;
 769         }
 770
 771         /*
 772          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 773          * till now so we have the "clean" result tuple type to create the new
 774          * table from.
 775          *
 776          * If EXPLAIN, skip creating the "into" relation.
 777          */
 778         intoRelationDesc = NULL;
 779
 780         if (do_select_into && !explainOnly)
 781         {
 782                 char       *intoName;
 783                 Oid                     namespaceId;
 784                 AclResult       aclresult;
 785                 Oid                     intoRelationId;
 786                 TupleDesc       tupdesc;
 787
 788                 /*
 789                  * find namespace to create in, check permissions
 790                  */
 791                 intoName = parseTree->into->relname;
 792                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 793
 794                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 795                                                                                   ACL_CREATE);
 796                 if (aclresult != ACLCHECK_OK)
 797                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 798                                                    get_namespace_name(namespaceId));
 799
 800                 /*
 801                  * have to copy tupType to get rid of constraints
 802                  */
 803                 tupdesc = CreateTupleDescCopy(tupType);
 804
 805                 intoRelationId = heap_create_with_catalog(intoName,
 806                                                                                                   namespaceId,
 807                                                                                                   tupdesc,
 808                                                                                                   RELKIND_RELATION,
 809                                                                                                   false,
 810                                                                                                   ONCOMMIT_NOOP,
 811                                                                                                   allowSystemTableMods);
 812
 813                 FreeTupleDesc(tupdesc);
 814
 815                 /*
 816                  * Advance command counter so that the newly-created relation's
 817                  * catalog tuples will be visible to heap_open.
 818                  */
 819                 CommandCounterIncrement();
 820
 821                 /*
 822                  * If necessary, create a TOAST table for the into relation. Note
 823                  * that AlterTableCreateToastTable ends with
 824                  * CommandCounterIncrement(), so that the TOAST table will be
 825                  * visible for insertion.
 826                  */
 827                 AlterTableCreateToastTable(intoRelationId, true);
 828
 829                 /*
 830                  * And open the constructed table for writing.
 831                  */
 832                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 833         }
 834
 835         estate->es_into_relation_descriptor = intoRelationDesc;
 836
 837         queryDesc->tupDesc = tupType;
 838         queryDesc->planstate = planstate;
 839 }
 840
 841 /*
 842  * Initialize ResultRelInfo data for one result relation
 843  */
 844 static void
 845 initResultRelInfo(ResultRelInfo *resultRelInfo,
 846                                   Index resultRelationIndex,
 847                                   List *rangeTable,
 848                                   CmdType operation)
 849 {
 850         Oid                     resultRelationOid;
 851         Relation        resultRelationDesc;
 852
 853         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 854         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 855
 856         switch (resultRelationDesc->rd_rel->relkind)
 857         {
 858                 case RELKIND_SEQUENCE:
 859                         ereport(ERROR,
 860                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 861                                          errmsg("cannot change sequence \"%s\"",
 862                                                   RelationGetRelationName(resultRelationDesc))));
 863                         break;
 864                 case RELKIND_TOASTVALUE:
 865                         ereport(ERROR,
 866                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 867                                          errmsg("cannot change TOAST relation \"%s\"",
 868                                                   RelationGetRelationName(resultRelationDesc))));
 869                         break;
 870                 case RELKIND_VIEW:
 871                         ereport(ERROR,
 872                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 873                                          errmsg("cannot change view \"%s\"",
 874                                                   RelationGetRelationName(resultRelationDesc))));
 875                         break;
 876         }
 877
 878         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 879         resultRelInfo->type = T_ResultRelInfo;
 880         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 881         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 882         resultRelInfo->ri_NumIndices = 0;
 883         resultRelInfo->ri_IndexRelationDescs = NULL;
 884         resultRelInfo->ri_IndexRelationInfo = NULL;
 885         /* make a copy so as not to depend on relcache info not changing... */
 886         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 887         resultRelInfo->ri_TrigFunctions = NULL;
 888         resultRelInfo->ri_ConstraintExprs = NULL;
 889         resultRelInfo->ri_junkFilter = NULL;
 890
 891         /*
 892          * If there are indices on the result relation, open them and save
 893          * descriptors in the result relation info, so that we can add new
 894          * index entries for the tuples we add/update.  We need not do this
 895          * for a DELETE, however, since deletion doesn't affect indexes.
 896          */
 897         if (resultRelationDesc->rd_rel->relhasindex &&
 898                 operation != CMD_DELETE)
 899                 ExecOpenIndices(resultRelInfo);
 900 }
 901
 902 /* ----------------------------------------------------------------
 903  *              ExecEndPlan
 904  *
 905  *              Cleans up the query plan -- closes files and frees up storage
 906  *
 907  * NOTE: we are no longer very worried about freeing storage per se
 908  * in this code; FreeExecutorState should be guaranteed to release all
 909  * memory that needs to be released.  What we are worried about doing
 910  * is closing relations and dropping buffer pins.  Thus, for example,
 911  * tuple tables must be cleared or dropped to ensure pins are released.
 912  * ----------------------------------------------------------------
 913  */
 914 void
 915 ExecEndPlan(PlanState *planstate, EState *estate)
 916 {
 917         ResultRelInfo *resultRelInfo;
 918         int                     i;
 919         List       *l;
 920
 921         /*
 922          * shut down any PlanQual processing we were doing
 923          */
 924         if (estate->es_evalPlanQual != NULL)
 925                 EndEvalPlanQual(estate);
 926
 927         /*
 928          * shut down the node-type-specific query processing
 929          */
 930         ExecEndNode(planstate);
 931
 932         /*
 933          * destroy the executor "tuple" table.
 934          */
 935         ExecDropTupleTable(estate->es_tupleTable, true);
 936         estate->es_tupleTable = NULL;
 937
 938         /*
 939          * close the result relation(s) if any, but hold locks until xact
 940          * commit.
 941          */
 942         resultRelInfo = estate->es_result_relations;
 943         for (i = estate->es_num_result_relations; i > 0; i--)
 944         {
 945                 /* Close indices and then the relation itself */
 946                 ExecCloseIndices(resultRelInfo);
 947                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 948                 resultRelInfo++;
 949         }
 950
 951         /*
 952          * close the "into" relation if necessary, again keeping lock
 953          */
 954         if (estate->es_into_relation_descriptor != NULL)
 955                 heap_close(estate->es_into_relation_descriptor, NoLock);
 956
 957         /*
 958          * close any relations selected FOR UPDATE, again keeping locks
 959          */
 960         foreach(l, estate->es_rowMark)
 961         {
 962                 execRowMark *erm = lfirst(l);
 963
 964                 heap_close(erm->relation, NoLock);
 965         }
 966 }
 967
 968 /* ----------------------------------------------------------------
 969  *              ExecutePlan
 970  *
 971  *              processes the query plan to retrieve 'numberTuples' tuples in the
 972  *              direction specified.
 973  *
 974  *              Retrieves all tuples if numberTuples is 0
 975  *
 976  *              result is either a slot containing the last tuple in the case
 977  *              of a SELECT or NULL otherwise.
 978  *
 979  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 980  * user can see it
 981  * ----------------------------------------------------------------
 982  */
 983 static TupleTableSlot *
 984 ExecutePlan(EState *estate,
 985                         PlanState *planstate,
 986                         CmdType operation,
 987                         long numberTuples,
 988                         ScanDirection direction,
 989                         DestReceiver *dest)
 990 {
 991         JunkFilter *junkfilter;
 992         TupleTableSlot *slot;
 993         ItemPointer tupleid = NULL;
 994         ItemPointerData tuple_ctid;
 995         long            current_tuple_count;
 996         TupleTableSlot *result;
 997
 998         /*
 999          * initialize local variables
1000          */
1001         slot = NULL;
1002         current_tuple_count = 0;
1003         result = NULL;
1004
1005         /*
1006          * Set the direction.
1007          */
1008         estate->es_direction = direction;
1009
1010         /*
1011          * Process BEFORE EACH STATEMENT triggers
1012          */
1013         switch (operation)
1014         {
1015                 case CMD_UPDATE:
1016                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
1017                         break;
1018                 case CMD_DELETE:
1019                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1020                         break;
1021                 case CMD_INSERT:
1022                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1023                         break;
1024                 default:
1025                         /* do nothing */
1026                         break;
1027         }
1028
1029         /*
1030          * Loop until we've processed the proper number of tuples from the
1031          * plan.
1032          */
1033
1034         for (;;)
1035         {
1036                 /* Reset the per-output-tuple exprcontext */
1037                 ResetPerTupleExprContext(estate);
1038
1039                 /*
1040                  * Execute the plan and obtain a tuple
1041                  */
1042 lnext:  ;
1043                 if (estate->es_useEvalPlan)
1044                 {
1045                         slot = EvalPlanQualNext(estate);
1046                         if (TupIsNull(slot))
1047                                 slot = ExecProcNode(planstate);
1048                 }
1049                 else
1050                         slot = ExecProcNode(planstate);
1051
1052                 /*
1053                  * if the tuple is null, then we assume there is nothing more to
1054                  * process so we just return null...
1055                  */
1056                 if (TupIsNull(slot))
1057                 {
1058                         result = NULL;
1059                         break;
1060                 }
1061
1062                 /*
1063                  * if we have a junk filter, then project a new tuple with the
1064                  * junk removed.
1065                  *
1066                  * Store this new "clean" tuple in the junkfilter's resultSlot.
1067                  * (Formerly, we stored it back over the "dirty" tuple, which is
1068                  * WRONG because that tuple slot has the wrong descriptor.)
1069                  *
1070                  * Also, extract all the junk information we need.
1071                  */
1072                 if ((junkfilter = estate->es_junkFilter) != NULL)
1073                 {
1074                         Datum           datum;
1075                         HeapTuple       newTuple;
1076                         bool            isNull;
1077
1078                         /*
1079                          * extract the 'ctid' junk attribute.
1080                          */
1081                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1082                         {
1083                                 if (!ExecGetJunkAttribute(junkfilter,
1084                                                                                   slot,
1085                                                                                   "ctid",
1086                                                                                   &datum,
1087                                                                                   &isNull))
1088                                         elog(ERROR, "could not find junk ctid column");
1089
1090                                 /* shouldn't ever get a null result... */
1091                                 if (isNull)
1092                                         elog(ERROR, "ctid is NULL");
1093
1094                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1095                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1096                                                                                  * ctid!! */
1097                                 tupleid = &tuple_ctid;
1098                         }
1099                         else if (estate->es_rowMark != NIL)
1100                         {
1101                                 List       *l;
1102
1103                 lmark:  ;
1104                                 foreach(l, estate->es_rowMark)
1105                                 {
1106                                         execRowMark *erm = lfirst(l);
1107                                         Buffer          buffer;
1108                                         HeapTupleData tuple;
1109                                         TupleTableSlot *newSlot;
1110                                         int                     test;
1111
1112                                         if (!ExecGetJunkAttribute(junkfilter,
1113                                                                                           slot,
1114                                                                                           erm->resname,
1115                                                                                           &datum,
1116                                                                                           &isNull))
1117                                                 elog(ERROR, "could not find junk \"%s\" column",
1118                                                          erm->resname);
1119
1120                                         /* shouldn't ever get a null result... */
1121                                         if (isNull)
1122                                                 elog(ERROR, "\"%s\" is NULL", erm->resname);
1123
1124                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1125                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1126                                                                                         estate->es_snapshot->curcid);
1127                                         ReleaseBuffer(buffer);
1128                                         switch (test)
1129                                         {
1130                                                 case HeapTupleSelfUpdated:
1131                                                         /* treat it as deleted; do not process */
1132                                                         goto lnext;
1133
1134                                                 case HeapTupleMayBeUpdated:
1135                                                         break;
1136
1137                                                 case HeapTupleUpdated:
1138                                                         if (IsXactIsoLevelSerializable)
1139                                                                 ereport(ERROR,
1140                                                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1141                                                                                  errmsg("could not serialize access due to concurrent update")));
1142                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1143                                                                   (ItemPointer) DatumGetPointer(datum))))
1144                                                         {
1145                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1146                                                                 if (!(TupIsNull(newSlot)))
1147                                                                 {
1148                                                                         slot = newSlot;
1149                                                                         estate->es_useEvalPlan = true;
1150                                                                         goto lmark;
1151                                                                 }
1152                                                         }
1153
1154                                                         /*
1155                                                          * if tuple was deleted or PlanQual failed for
1156                                                          * updated tuple - we must not return this
1157                                                          * tuple!
1158                                                          */
1159                                                         goto lnext;
1160
1161                                                 default:
1162                                                         elog(ERROR, "unrecognized heap_mark4update status: %u",
1163                                                                  test);
1164                                                         return (NULL);
1165                                         }
1166                                 }
1167                         }
1168
1169                         /*
1170                          * Finally create a new "clean" tuple with all junk attributes
1171                          * removed
1172                          */
1173                         newTuple = ExecRemoveJunk(junkfilter, slot);
1174
1175                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1176                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1177                                                                   InvalidBuffer,                /* this tuple has no
1178                                                                                                                  * buffer */
1179                                                                   true);                /* tuple should be pfreed */
1180                 }
1181
1182                 /*
1183                  * now that we have a tuple, do the appropriate thing with it..
1184                  * either return it to the user, add it to a relation someplace,
1185                  * delete it from a relation, or modify some of its attributes.
1186                  */
1187                 switch (operation)
1188                 {
1189                         case CMD_SELECT:
1190                                 ExecSelect(slot,        /* slot containing tuple */
1191                                                    dest,        /* destination's tuple-receiver obj */
1192                                                    estate);
1193                                 result = slot;
1194                                 break;
1195
1196                         case CMD_INSERT:
1197                                 ExecInsert(slot, tupleid, estate);
1198                                 result = NULL;
1199                                 break;
1200
1201                         case CMD_DELETE:
1202                                 ExecDelete(slot, tupleid, estate);
1203                                 result = NULL;
1204                                 break;
1205
1206                         case CMD_UPDATE:
1207                                 ExecUpdate(slot, tupleid, estate);
1208                                 result = NULL;
1209                                 break;
1210
1211                         default:
1212                                 elog(ERROR, "unrecognized operation code: %d",
1213                                          (int) operation);
1214                                 result = NULL;
1215                                 break;
1216                 }
1217
1218                 /*
1219                  * check our tuple count.. if we've processed the proper number
1220                  * then quit, else loop again and process more tuples.  Zero
1221                  * numberTuples means no limit.
1222                  */
1223                 current_tuple_count++;
1224                 if (numberTuples && numberTuples == current_tuple_count)
1225                         break;
1226         }
1227
1228         /*
1229          * Process AFTER EACH STATEMENT triggers
1230          */
1231         switch (operation)
1232         {
1233                 case CMD_UPDATE:
1234                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1235                         break;
1236                 case CMD_DELETE:
1237                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1238                         break;
1239                 case CMD_INSERT:
1240                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1241                         break;
1242                 default:
1243                         /* do nothing */
1244                         break;
1245         }
1246
1247         /*
1248          * here, result is either a slot containing a tuple in the case of a
1249          * SELECT or NULL otherwise.
1250          */
1251         return result;
1252 }
1253
1254 /* ----------------------------------------------------------------
1255  *              ExecSelect
1256  *
1257  *              SELECTs are easy.. we just pass the tuple to the appropriate
1258  *              print function.  The only complexity is when we do a
1259  *              "SELECT INTO", in which case we insert the tuple into
1260  *              the appropriate relation (note: this is a newly created relation
1261  *              so we don't need to worry about indices or locks.)
1262  * ----------------------------------------------------------------
1263  */
1264 static void
1265 ExecSelect(TupleTableSlot *slot,
1266                    DestReceiver *dest,
1267                    EState *estate)
1268 {
1269         HeapTuple       tuple;
1270         TupleDesc       attrtype;
1271
1272         /*
1273          * get the heap tuple out of the tuple table slot
1274          */
1275         tuple = slot->val;
1276         attrtype = slot->ttc_tupleDescriptor;
1277
1278         /*
1279          * insert the tuple into the "into relation"
1280          *
1281          * XXX this probably ought to be replaced by a separate destination
1282          */
1283         if (estate->es_into_relation_descriptor != NULL)
1284         {
1285                 heap_insert(estate->es_into_relation_descriptor, tuple,
1286                                         estate->es_snapshot->curcid);
1287                 IncrAppended();
1288         }
1289
1290         /*
1291          * send the tuple to the destination
1292          */
1293         (*dest->receiveTuple) (tuple, attrtype, dest);
1294         IncrRetrieved();
1295         (estate->es_processed)++;
1296 }
1297
1298 /* ----------------------------------------------------------------
1299  *              ExecInsert
1300  *
1301  *              INSERTs are trickier.. we have to insert the tuple into
1302  *              the base relation and insert appropriate tuples into the
1303  *              index relations.
1304  * ----------------------------------------------------------------
1305  */
1306 static void
1307 ExecInsert(TupleTableSlot *slot,
1308                    ItemPointer tupleid,
1309                    EState *estate)
1310 {
1311         HeapTuple       tuple;
1312         ResultRelInfo *resultRelInfo;
1313         Relation        resultRelationDesc;
1314         int                     numIndices;
1315         Oid                     newId;
1316
1317         /*
1318          * get the heap tuple out of the tuple table slot
1319          */
1320         tuple = slot->val;
1321
1322         /*
1323          * get information on the (current) result relation
1324          */
1325         resultRelInfo = estate->es_result_relation_info;
1326         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1327
1328         /* BEFORE ROW INSERT Triggers */
1329         if (resultRelInfo->ri_TrigDesc &&
1330           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1331         {
1332                 HeapTuple       newtuple;
1333
1334                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1335
1336                 if (newtuple == NULL)   /* "do nothing" */
1337                         return;
1338
1339                 if (newtuple != tuple)  /* modified by Trigger(s) */
1340                 {
1341                         /*
1342                          * Insert modified tuple into tuple table slot, replacing the
1343                          * original.  We assume that it was allocated in per-tuple
1344                          * memory context, and therefore will go away by itself. The
1345                          * tuple table slot should not try to clear it.
1346                          */
1347                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1348                         tuple = newtuple;
1349                 }
1350         }
1351
1352         /*
1353          * Check the constraints of the tuple
1354          */
1355         if (resultRelationDesc->rd_att->constr)
1356                 ExecConstraints(resultRelInfo, slot, estate);
1357
1358         /*
1359          * insert the tuple
1360          */
1361         newId = heap_insert(resultRelationDesc, tuple,
1362                                                 estate->es_snapshot->curcid);
1363
1364         IncrAppended();
1365         (estate->es_processed)++;
1366         estate->es_lastoid = newId;
1367         setLastTid(&(tuple->t_self));
1368
1369         /*
1370          * process indices
1371          *
1372          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1373          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1374          * field.
1375          */
1376         numIndices = resultRelInfo->ri_NumIndices;
1377         if (numIndices > 0)
1378                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1379
1380         /* AFTER ROW INSERT Triggers */
1381         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1382 }
1383
1384 /* ----------------------------------------------------------------
1385  *              ExecDelete
1386  *
1387  *              DELETE is like UPDATE, we delete the tuple and its
1388  *              index tuples.
1389  * ----------------------------------------------------------------
1390  */
1391 static void
1392 ExecDelete(TupleTableSlot *slot,
1393                    ItemPointer tupleid,
1394                    EState *estate)
1395 {
1396         ResultRelInfo *resultRelInfo;
1397         Relation        resultRelationDesc;
1398         ItemPointerData ctid;
1399         int                     result;
1400
1401         /*
1402          * get information on the (current) result relation
1403          */
1404         resultRelInfo = estate->es_result_relation_info;
1405         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1406
1407         /* BEFORE ROW DELETE Triggers */
1408         if (resultRelInfo->ri_TrigDesc &&
1409           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1410         {
1411                 bool            dodelete;
1412
1413                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1414                                                                                 estate->es_snapshot->curcid);
1415
1416                 if (!dodelete)                  /* "do nothing" */
1417                         return;
1418         }
1419
1420         /*
1421          * delete the tuple
1422          */
1423 ldelete:;
1424         result = heap_delete(resultRelationDesc, tupleid,
1425                                                  &ctid,
1426                                                  estate->es_snapshot->curcid,
1427                                                  estate->es_crosscheck_snapshot,
1428                                                  true /* wait for commit */);
1429         switch (result)
1430         {
1431                 case HeapTupleSelfUpdated:
1432                         /* already deleted by self; nothing to do */
1433                         return;
1434
1435                 case HeapTupleMayBeUpdated:
1436                         break;
1437
1438                 case HeapTupleUpdated:
1439                         if (IsXactIsoLevelSerializable)
1440                                 ereport(ERROR,
1441                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1442                                                  errmsg("could not serialize access due to concurrent update")));
1443                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1444                         {
1445                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1446                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1447
1448                                 if (!TupIsNull(epqslot))
1449                                 {
1450                                         *tupleid = ctid;
1451                                         goto ldelete;
1452                                 }
1453                         }
1454                         /* tuple already deleted; nothing to do */
1455                         return;
1456
1457                 default:
1458                         elog(ERROR, "unrecognized heap_delete status: %u", result);
1459                         return;
1460         }
1461
1462         IncrDeleted();
1463         (estate->es_processed)++;
1464
1465         /*
1466          * Note: Normally one would think that we have to delete index tuples
1467          * associated with the heap tuple now..
1468          *
1469          * ... but in POSTGRES, we have no need to do this because the vacuum
1470          * daemon automatically opens an index scan and deletes index tuples
1471          * when it finds deleted heap tuples. -cim 9/27/89
1472          */
1473
1474         /* AFTER ROW DELETE Triggers */
1475         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1476 }
1477
1478 /* ----------------------------------------------------------------
1479  *              ExecUpdate
1480  *
1481  *              note: we can't run UPDATE queries with transactions
1482  *              off because UPDATEs are actually INSERTs and our
1483  *              scan will mistakenly loop forever, updating the tuple
1484  *              it just inserted..      This should be fixed but until it
1485  *              is, we don't want to get stuck in an infinite loop
1486  *              which corrupts your database..
1487  * ----------------------------------------------------------------
1488  */
1489 static void
1490 ExecUpdate(TupleTableSlot *slot,
1491                    ItemPointer tupleid,
1492                    EState *estate)
1493 {
1494         HeapTuple       tuple;
1495         ResultRelInfo *resultRelInfo;
1496         Relation        resultRelationDesc;
1497         ItemPointerData ctid;
1498         int                     result;
1499         int                     numIndices;
1500
1501         /*
1502          * abort the operation if not running transactions
1503          */
1504         if (IsBootstrapProcessingMode())
1505                 elog(ERROR, "cannot UPDATE during bootstrap");
1506
1507         /*
1508          * get the heap tuple out of the tuple table slot
1509          */
1510         tuple = slot->val;
1511
1512         /*
1513          * get information on the (current) result relation
1514          */
1515         resultRelInfo = estate->es_result_relation_info;
1516         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1517
1518         /* BEFORE ROW UPDATE Triggers */
1519         if (resultRelInfo->ri_TrigDesc &&
1520           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1521         {
1522                 HeapTuple       newtuple;
1523
1524                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1525                                                                                 tupleid, tuple,
1526                                                                                 estate->es_snapshot->curcid);
1527
1528                 if (newtuple == NULL)   /* "do nothing" */
1529                         return;
1530
1531                 if (newtuple != tuple)  /* modified by Trigger(s) */
1532                 {
1533                         /*
1534                          * Insert modified tuple into tuple table slot, replacing the
1535                          * original.  We assume that it was allocated in per-tuple
1536                          * memory context, and therefore will go away by itself. The
1537                          * tuple table slot should not try to clear it.
1538                          */
1539                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1540                         tuple = newtuple;
1541                 }
1542         }
1543
1544         /*
1545          * Check the constraints of the tuple
1546          *
1547          * If we generate a new candidate tuple after EvalPlanQual testing, we
1548          * must loop back here and recheck constraints.  (We don't need to
1549          * redo triggers, however.      If there are any BEFORE triggers then
1550          * trigger.c will have done mark4update to lock the correct tuple, so
1551          * there's no need to do them again.)
1552          */
1553 lreplace:;
1554         if (resultRelationDesc->rd_att->constr)
1555                 ExecConstraints(resultRelInfo, slot, estate);
1556
1557         /*
1558          * replace the heap tuple
1559          */
1560         result = heap_update(resultRelationDesc, tupleid, tuple,
1561                                                  &ctid,
1562                                                  estate->es_snapshot->curcid,
1563                                                  estate->es_crosscheck_snapshot,
1564                                                  true /* wait for commit */);
1565         switch (result)
1566         {
1567                 case HeapTupleSelfUpdated:
1568                         /* already deleted by self; nothing to do */
1569                         return;
1570
1571                 case HeapTupleMayBeUpdated:
1572                         break;
1573
1574                 case HeapTupleUpdated:
1575                         if (IsXactIsoLevelSerializable)
1576                                 ereport(ERROR,
1577                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1578                                                  errmsg("could not serialize access due to concurrent update")));
1579                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1580                         {
1581                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1582                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1583
1584                                 if (!TupIsNull(epqslot))
1585                                 {
1586                                         *tupleid = ctid;
1587                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1588                                         slot = ExecStoreTuple(tuple,
1589                                                                         estate->es_junkFilter->jf_resultSlot,
1590                                                                                   InvalidBuffer, true);
1591                                         goto lreplace;
1592                                 }
1593                         }
1594                         /* tuple already deleted; nothing to do */
1595                         return;
1596
1597                 default:
1598                         elog(ERROR, "unrecognized heap_update status: %u", result);
1599                         return;
1600         }
1601
1602         IncrReplaced();
1603         (estate->es_processed)++;
1604
1605         /*
1606          * Note: instead of having to update the old index tuples associated
1607          * with the heap tuple, all we do is form and insert new index tuples.
1608          * This is because UPDATEs are actually DELETEs and INSERTs and index
1609          * tuple deletion is done automagically by the vacuum daemon. All we
1610          * do is insert new index tuples.  -cim 9/27/89
1611          */
1612
1613         /*
1614          * process indices
1615          *
1616          * heap_update updates a tuple in the base relation by invalidating it
1617          * and then inserting a new tuple to the relation.      As a side effect,
1618          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1619          * field.  So we now insert index tuples using the new tupleid stored
1620          * there.
1621          */
1622
1623         numIndices = resultRelInfo->ri_NumIndices;
1624         if (numIndices > 0)
1625                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1626
1627         /* AFTER ROW UPDATE Triggers */
1628         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1629 }
1630
1631 static const char *
1632 ExecRelCheck(ResultRelInfo *resultRelInfo,
1633                          TupleTableSlot *slot, EState *estate)
1634 {
1635         Relation        rel = resultRelInfo->ri_RelationDesc;
1636         int                     ncheck = rel->rd_att->constr->num_check;
1637         ConstrCheck *check = rel->rd_att->constr->check;
1638         ExprContext *econtext;
1639         MemoryContext oldContext;
1640         List       *qual;
1641         int                     i;
1642
1643         /*
1644          * If first time through for this result relation, build expression
1645          * nodetrees for rel's constraint expressions.  Keep them in the
1646          * per-query memory context so they'll survive throughout the query.
1647          */
1648         if (resultRelInfo->ri_ConstraintExprs == NULL)
1649         {
1650                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1651                 resultRelInfo->ri_ConstraintExprs =
1652                         (List **) palloc(ncheck * sizeof(List *));
1653                 for (i = 0; i < ncheck; i++)
1654                 {
1655                         /* ExecQual wants implicit-AND form */
1656                         qual = make_ands_implicit(stringToNode(check[i].ccbin));
1657                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1658                                 ExecPrepareExpr((Expr *) qual, estate);
1659                 }
1660                 MemoryContextSwitchTo(oldContext);
1661         }
1662
1663         /*
1664          * We will use the EState's per-tuple context for evaluating
1665          * constraint expressions (creating it if it's not already there).
1666          */
1667         econtext = GetPerTupleExprContext(estate);
1668
1669         /* Arrange for econtext's scan tuple to be the tuple under test */
1670         econtext->ecxt_scantuple = slot;
1671
1672         /* And evaluate the constraints */
1673         for (i = 0; i < ncheck; i++)
1674         {
1675                 qual = resultRelInfo->ri_ConstraintExprs[i];
1676
1677                 /*
1678                  * NOTE: SQL92 specifies that a NULL result from a constraint
1679                  * expression is not to be treated as a failure.  Therefore, tell
1680                  * ExecQual to return TRUE for NULL.
1681                  */
1682                 if (!ExecQual(qual, econtext, true))
1683                         return check[i].ccname;
1684         }
1685
1686         /* NULL result means no error */
1687         return NULL;
1688 }
1689
1690 void
1691 ExecConstraints(ResultRelInfo *resultRelInfo,
1692                                 TupleTableSlot *slot, EState *estate)
1693 {
1694         Relation        rel = resultRelInfo->ri_RelationDesc;
1695         HeapTuple       tuple = slot->val;
1696         TupleConstr *constr = rel->rd_att->constr;
1697
1698         Assert(constr);
1699
1700         if (constr->has_not_null)
1701         {
1702                 int                     natts = rel->rd_att->natts;
1703                 int                     attrChk;
1704
1705                 for (attrChk = 1; attrChk <= natts; attrChk++)
1706                 {
1707                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1708                                 heap_attisnull(tuple, attrChk))
1709                                 ereport(ERROR,
1710                                                 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1711                                                  errmsg("null value in column \"%s\" violates not-null constraint",
1712                                         NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1713                 }
1714         }
1715
1716         if (constr->num_check > 0)
1717         {
1718                 const char *failed;
1719
1720                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1721                         ereport(ERROR,
1722                                         (errcode(ERRCODE_CHECK_VIOLATION),
1723                                          errmsg("new row for relation \"%s\" violates check constraint \"%s\"",
1724                                                         RelationGetRelationName(rel), failed)));
1725         }
1726 }
1727
1728 /*
1729  * Check a modified tuple to see if we want to process its updated version
1730  * under READ COMMITTED rules.
1731  *
1732  * See backend/executor/README for some info about how this works.
1733  */
1734 TupleTableSlot *
1735 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1736 {
1737         evalPlanQual *epq;
1738         EState     *epqstate;
1739         Relation        relation;
1740         HeapTupleData tuple;
1741         HeapTuple       copyTuple = NULL;
1742         bool            endNode;
1743
1744         Assert(rti != 0);
1745
1746         /*
1747          * find relation containing target tuple
1748          */
1749         if (estate->es_result_relation_info != NULL &&
1750                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1751                 relation = estate->es_result_relation_info->ri_RelationDesc;
1752         else
1753         {
1754                 List       *l;
1755
1756                 relation = NULL;
1757                 foreach(l, estate->es_rowMark)
1758                 {
1759                         if (((execRowMark *) lfirst(l))->rti == rti)
1760                         {
1761                                 relation = ((execRowMark *) lfirst(l))->relation;
1762                                 break;
1763                         }
1764                 }
1765                 if (relation == NULL)
1766                         elog(ERROR, "could not find RowMark for RT index %u", rti);
1767         }
1768
1769         /*
1770          * fetch tid tuple
1771          *
1772          * Loop here to deal with updated or busy tuples
1773          */
1774         tuple.t_self = *tid;
1775         for (;;)
1776         {
1777                 Buffer          buffer;
1778
1779                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1780                 {
1781                         TransactionId xwait = SnapshotDirty->xmax;
1782
1783                         /* xmin should not be dirty... */
1784                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1785                                 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1786
1787                         /*
1788                          * If tuple is being updated by other transaction then we have
1789                          * to wait for its commit/abort.
1790                          */
1791                         if (TransactionIdIsValid(xwait))
1792                         {
1793                                 ReleaseBuffer(buffer);
1794                                 XactLockTableWait(xwait);
1795                                 continue;
1796                         }
1797
1798                         /*
1799                          * We got tuple - now copy it for use by recheck query.
1800                          */
1801                         copyTuple = heap_copytuple(&tuple);
1802                         ReleaseBuffer(buffer);
1803                         break;
1804                 }
1805
1806                 /*
1807                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1808                  * Note that it's possible to get invalid SnapshotDirty->tid if
1809                  * tuple updated by this transaction. Have we to check this ?
1810                  */
1811                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1812                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1813                 {
1814                         /* updated, so look at the updated copy */
1815                         tuple.t_self = SnapshotDirty->tid;
1816                         continue;
1817                 }
1818
1819                 /*
1820                  * Deleted or updated by this transaction; forget it.
1821                  */
1822                 return NULL;
1823         }
1824
1825         /*
1826          * For UPDATE/DELETE we have to return tid of actual row we're
1827          * executing PQ for.
1828          */
1829         *tid = tuple.t_self;
1830
1831         /*
1832          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1833          */
1834         epq = estate->es_evalPlanQual;
1835         endNode = true;
1836
1837         if (epq != NULL && epq->rti == 0)
1838         {
1839                 /* Top PQ stack entry is idle, so re-use it */
1840                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1841                 epq->rti = rti;
1842                 endNode = false;
1843         }
1844
1845         /*
1846          * If this is request for another RTE - Ra, - then we have to check
1847          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1848          * updated again and we have to re-start old execution for Ra and
1849          * forget all what we done after Ra was suspended. Cool? -:))
1850          */
1851         if (epq != NULL && epq->rti != rti &&
1852                 epq->estate->es_evTuple[rti - 1] != NULL)
1853         {
1854                 do
1855                 {
1856                         evalPlanQual *oldepq;
1857
1858                         /* stop execution */
1859                         EvalPlanQualStop(epq);
1860                         /* pop previous PlanQual from the stack */
1861                         oldepq = epq->next;
1862                         Assert(oldepq && oldepq->rti != 0);
1863                         /* push current PQ to freePQ stack */
1864                         oldepq->free = epq;
1865                         epq = oldepq;
1866                         estate->es_evalPlanQual = epq;
1867                 } while (epq->rti != rti);
1868         }
1869
1870         /*
1871          * If we are requested for another RTE then we have to suspend
1872          * execution of current PlanQual and start execution for new one.
1873          */
1874         if (epq == NULL || epq->rti != rti)
1875         {
1876                 /* try to reuse plan used previously */
1877                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1878
1879                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1880                 {
1881                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1882                         newepq->free = NULL;
1883                         newepq->estate = NULL;
1884                         newepq->planstate = NULL;
1885                 }
1886                 else
1887                 {
1888                         /* recycle previously used PlanQual */
1889                         Assert(newepq->estate == NULL);
1890                         epq->free = NULL;
1891                 }
1892                 /* push current PQ to the stack */
1893                 newepq->next = epq;
1894                 epq = newepq;
1895                 estate->es_evalPlanQual = epq;
1896                 epq->rti = rti;
1897                 endNode = false;
1898         }
1899
1900         Assert(epq->rti == rti);
1901
1902         /*
1903          * Ok - we're requested for the same RTE.  Unfortunately we still have
1904          * to end and restart execution of the plan, because ExecReScan
1905          * wouldn't ensure that upper plan nodes would reset themselves.  We
1906          * could make that work if insertion of the target tuple were
1907          * integrated with the Param mechanism somehow, so that the upper plan
1908          * nodes know that their children's outputs have changed.
1909          *
1910          * Note that the stack of free evalPlanQual nodes is quite useless at the
1911          * moment, since it only saves us from pallocing/releasing the
1912          * evalPlanQual nodes themselves.  But it will be useful once we
1913          * implement ReScan instead of end/restart for re-using PlanQual
1914          * nodes.
1915          */
1916         if (endNode)
1917         {
1918                 /* stop execution */
1919                 EvalPlanQualStop(epq);
1920         }
1921
1922         /*
1923          * Initialize new recheck query.
1924          *
1925          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to
1926          * instead copy down changeable state from the top plan (including
1927          * es_result_relation_info, es_junkFilter) and reset locally
1928          * changeable state in the epq (including es_param_exec_vals,
1929          * es_evTupleNull).
1930          */
1931         EvalPlanQualStart(epq, estate, epq->next);
1932
1933         /*
1934          * free old RTE' tuple, if any, and store target tuple where
1935          * relation's scan node will see it
1936          */
1937         epqstate = epq->estate;
1938         if (epqstate->es_evTuple[rti - 1] != NULL)
1939                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1940         epqstate->es_evTuple[rti - 1] = copyTuple;
1941
1942         return EvalPlanQualNext(estate);
1943 }
1944
1945 static TupleTableSlot *
1946 EvalPlanQualNext(EState *estate)
1947 {
1948         evalPlanQual *epq = estate->es_evalPlanQual;
1949         MemoryContext oldcontext;
1950         TupleTableSlot *slot;
1951
1952         Assert(epq->rti != 0);
1953
1954 lpqnext:;
1955         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1956         slot = ExecProcNode(epq->planstate);
1957         MemoryContextSwitchTo(oldcontext);
1958
1959         /*
1960          * No more tuples for this PQ. Continue previous one.
1961          */
1962         if (TupIsNull(slot))
1963         {
1964                 evalPlanQual *oldepq;
1965
1966                 /* stop execution */
1967                 EvalPlanQualStop(epq);
1968                 /* pop old PQ from the stack */
1969                 oldepq = epq->next;
1970                 if (oldepq == NULL)
1971                 {
1972                         /* this is the first (oldest) PQ - mark as free */
1973                         epq->rti = 0;
1974                         estate->es_useEvalPlan = false;
1975                         /* and continue Query execution */
1976                         return (NULL);
1977                 }
1978                 Assert(oldepq->rti != 0);
1979                 /* push current PQ to freePQ stack */
1980                 oldepq->free = epq;
1981                 epq = oldepq;
1982                 estate->es_evalPlanQual = epq;
1983                 goto lpqnext;
1984         }
1985
1986         return (slot);
1987 }
1988
1989 static void
1990 EndEvalPlanQual(EState *estate)
1991 {
1992         evalPlanQual *epq = estate->es_evalPlanQual;
1993
1994         if (epq->rti == 0)                      /* plans already shutdowned */
1995         {
1996                 Assert(epq->next == NULL);
1997                 return;
1998         }
1999
2000         for (;;)
2001         {
2002                 evalPlanQual *oldepq;
2003
2004                 /* stop execution */
2005                 EvalPlanQualStop(epq);
2006                 /* pop old PQ from the stack */
2007                 oldepq = epq->next;
2008                 if (oldepq == NULL)
2009                 {
2010                         /* this is the first (oldest) PQ - mark as free */
2011                         epq->rti = 0;
2012                         estate->es_useEvalPlan = false;
2013                         break;
2014                 }
2015                 Assert(oldepq->rti != 0);
2016                 /* push current PQ to freePQ stack */
2017                 oldepq->free = epq;
2018                 epq = oldepq;
2019                 estate->es_evalPlanQual = epq;
2020         }
2021 }
2022
2023 /*
2024  * Start execution of one level of PlanQual.
2025  *
2026  * This is a cut-down version of ExecutorStart(): we copy some state from
2027  * the top-level estate rather than initializing it fresh.
2028  */
2029 static void
2030 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2031 {
2032         EState     *epqstate;
2033         int                     rtsize;
2034         MemoryContext oldcontext;
2035
2036         rtsize = length(estate->es_range_table);
2037
2038         epq->estate = epqstate = CreateExecutorState();
2039
2040         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2041
2042         /*
2043          * The epqstates share the top query's copy of unchanging state such
2044          * as the snapshot, rangetable, result-rel info, and external Param
2045          * info. They need their own copies of local state, including a tuple
2046          * table, es_param_exec_vals, etc.
2047          */
2048         epqstate->es_direction = ForwardScanDirection;
2049         epqstate->es_snapshot = estate->es_snapshot;
2050         epqstate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
2051         epqstate->es_range_table = estate->es_range_table;
2052         epqstate->es_result_relations = estate->es_result_relations;
2053         epqstate->es_num_result_relations = estate->es_num_result_relations;
2054         epqstate->es_result_relation_info = estate->es_result_relation_info;
2055         epqstate->es_junkFilter = estate->es_junkFilter;
2056         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2057         epqstate->es_param_list_info = estate->es_param_list_info;
2058         if (estate->es_topPlan->nParamExec > 0)
2059                 epqstate->es_param_exec_vals = (ParamExecData *)
2060                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2061         epqstate->es_rowMark = estate->es_rowMark;
2062         epqstate->es_instrument = estate->es_instrument;
2063         epqstate->es_force_oids = estate->es_force_oids;
2064         epqstate->es_topPlan = estate->es_topPlan;
2065
2066         /*
2067          * Each epqstate must have its own es_evTupleNull state, but all the
2068          * stack entries share es_evTuple state.  This allows sub-rechecks to
2069          * inherit the value being examined by an outer recheck.
2070          */
2071         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2072         if (priorepq == NULL)
2073                 /* first PQ stack entry */
2074                 epqstate->es_evTuple = (HeapTuple *)
2075                         palloc0(rtsize * sizeof(HeapTuple));
2076         else
2077                 /* later stack entries share the same storage */
2078                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2079
2080         epqstate->es_tupleTable =
2081                 ExecCreateTupleTable(estate->es_tupleTable->size);
2082
2083         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2084
2085         MemoryContextSwitchTo(oldcontext);
2086 }
2087
2088 /*
2089  * End execution of one level of PlanQual.
2090  *
2091  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2092  * of the normal cleanup, but *not* close result relations (which we are
2093  * just sharing from the outer query).
2094  */
2095 static void
2096 EvalPlanQualStop(evalPlanQual *epq)
2097 {
2098         EState     *epqstate = epq->estate;
2099         MemoryContext oldcontext;
2100
2101         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2102
2103         ExecEndNode(epq->planstate);
2104
2105         ExecDropTupleTable(epqstate->es_tupleTable, true);
2106         epqstate->es_tupleTable = NULL;
2107
2108         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2109         {
2110                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2111                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2112         }
2113
2114         MemoryContextSwitchTo(oldcontext);
2115
2116         FreeExecutorState(epqstate);
2117
2118         epq->estate = NULL;
2119         epq->planstate = NULL;
2120 }