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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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) 1996-2002, PostgreSQL Global Development Group
  25  * Portions Copyright (c) 1994, Regents of the University of California
  26  *
  27  *
  28  * IDENTIFICATION
  29  *        $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.212 2003/08/01 00:15:20 tgl 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/var.h"
  44 #include "parser/parsetree.h"
  45 #include "utils/acl.h"
  46 #include "utils/lsyscache.h"
  47
  48
  49 typedef struct execRowMark
  50 {
  51         Relation        relation;
  52         Index           rti;
  53         char            resname[32];
  54 } execRowMark;
  55
  56 typedef struct evalPlanQual
  57 {
  58         Index           rti;
  59         EState     *estate;
  60         PlanState  *planstate;
  61         struct evalPlanQual *next;      /* stack of active PlanQual plans */
  62         struct evalPlanQual *free;      /* list of free PlanQual plans */
  63 } evalPlanQual;
  64
  65 /* decls for local routines only used within this module */
  66 static void InitPlan(QueryDesc *queryDesc, bool explainOnly);
  67 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  68                                   Index resultRelationIndex,
  69                                   List *rangeTable,
  70                                   CmdType operation);
  71 static TupleTableSlot *ExecutePlan(EState *estate, PlanState *planstate,
  72                         CmdType operation,
  73                         long numberTuples,
  74                         ScanDirection direction,
  75                         DestReceiver *dest);
  76 static void ExecSelect(TupleTableSlot *slot,
  77                    DestReceiver *dest,
  78                    EState *estate);
  79 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
  80                    EState *estate);
  81 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  82                    EState *estate);
  83 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
  84                    EState *estate);
  85 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  86 static void EndEvalPlanQual(EState *estate);
  87 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
  88 static void ExecCheckXactReadOnly(Query *parsetree, CmdType operation);
  89 static void EvalPlanQualStart(evalPlanQual *epq, EState *estate,
  90                                                           evalPlanQual *priorepq);
  91 static void EvalPlanQualStop(evalPlanQual *epq);
  92
  93 /* end of local decls */
  94
  95
  96 /* ----------------------------------------------------------------
  97  *              ExecutorStart
  98  *
  99  *              This routine must be called at the beginning of any execution of any
 100  *              query plan
 101  *
 102  * Takes a QueryDesc previously created by CreateQueryDesc (it's not real
 103  * clear why we bother to separate the two functions, but...).  The tupDesc
 104  * field of the QueryDesc is filled in to describe the tuples that will be
 105  * returned, and the internal fields (estate and planstate) are set up.
 106  *
 107  * If explainOnly is true, we are not actually intending to run the plan,
 108  * only to set up for EXPLAIN; so skip unwanted side-effects.
 109  *
 110  * NB: the CurrentMemoryContext when this is called will become the parent
 111  * of the per-query context used for this Executor invocation.
 112  * ----------------------------------------------------------------
 113  */
 114 void
 115 ExecutorStart(QueryDesc *queryDesc, bool explainOnly)
 116 {
 117         EState     *estate;
 118         MemoryContext oldcontext;
 119
 120         /* sanity checks: queryDesc must not be started already */
 121         Assert(queryDesc != NULL);
 122         Assert(queryDesc->estate == NULL);
 123
 124         /*
 125          * If the transaction is read-only, we need to check if any writes
 126          * are planned to non-temporary tables.
 127          */
 128         if (!explainOnly)
 129                 ExecCheckXactReadOnly(queryDesc->parsetree, queryDesc->operation);
 130
 131         /*
 132          * Build EState, switch into per-query memory context for startup.
 133          */
 134         estate = CreateExecutorState();
 135         queryDesc->estate = estate;
 136
 137         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 138
 139         /*
 140          * Fill in parameters, if any, from queryDesc
 141          */
 142         estate->es_param_list_info = queryDesc->params;
 143
 144         if (queryDesc->plantree->nParamExec > 0)
 145                 estate->es_param_exec_vals = (ParamExecData *)
 146                         palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 147
 148         estate->es_instrument = queryDesc->doInstrument;
 149
 150         /*
 151          * Make our own private copy of the current query snapshot data.
 152          *
 153          * This "freezes" our idea of which tuples are good and which are not for
 154          * the life of this query, even if it outlives the current command and
 155          * current snapshot.
 156          */
 157         estate->es_snapshot = CopyQuerySnapshot();
 158
 159         /*
 160          * Initialize the plan state tree
 161          */
 162         InitPlan(queryDesc, explainOnly);
 163
 164         MemoryContextSwitchTo(oldcontext);
 165 }
 166
 167 /* ----------------------------------------------------------------
 168  *              ExecutorRun
 169  *
 170  *              This is the main routine of the executor module. It accepts
 171  *              the query descriptor from the traffic cop and executes the
 172  *              query plan.
 173  *
 174  *              ExecutorStart must have been called already.
 175  *
 176  *              If direction is NoMovementScanDirection then nothing is done
 177  *              except to start up/shut down the destination.  Otherwise,
 178  *              we retrieve up to 'count' tuples in the specified direction.
 179  *
 180  *              Note: count = 0 is interpreted as no portal limit, i.e., run to
 181  *              completion.
 182  *
 183  * ----------------------------------------------------------------
 184  */
 185 TupleTableSlot *
 186 ExecutorRun(QueryDesc *queryDesc,
 187                         ScanDirection direction, long count)
 188 {
 189         EState     *estate;
 190         CmdType         operation;
 191         DestReceiver *dest;
 192         TupleTableSlot *result;
 193         MemoryContext oldcontext;
 194
 195         /* sanity checks */
 196         Assert(queryDesc != NULL);
 197
 198         estate = queryDesc->estate;
 199
 200         Assert(estate != NULL);
 201
 202         /*
 203          * Switch into per-query memory context
 204          */
 205         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 206
 207         /*
 208          * extract information from the query descriptor and the query
 209          * feature.
 210          */
 211         operation = queryDesc->operation;
 212         dest = queryDesc->dest;
 213
 214         /*
 215          * startup tuple receiver
 216          */
 217         estate->es_processed = 0;
 218         estate->es_lastoid = InvalidOid;
 219
 220         (*dest->startup) (dest, operation, queryDesc->tupDesc);
 221
 222         /*
 223          * run plan
 224          */
 225         if (direction == NoMovementScanDirection)
 226                 result = NULL;
 227         else
 228                 result = ExecutePlan(estate,
 229                                                          queryDesc->planstate,
 230                                                          operation,
 231                                                          count,
 232                                                          direction,
 233                                                          dest);
 234
 235         /*
 236          * shutdown receiver
 237          */
 238         (*dest->shutdown) (dest);
 239
 240         MemoryContextSwitchTo(oldcontext);
 241
 242         return result;
 243 }
 244
 245 /* ----------------------------------------------------------------
 246  *              ExecutorEnd
 247  *
 248  *              This routine must be called at the end of execution of any
 249  *              query plan
 250  * ----------------------------------------------------------------
 251  */
 252 void
 253 ExecutorEnd(QueryDesc *queryDesc)
 254 {
 255         EState     *estate;
 256         MemoryContext oldcontext;
 257
 258         /* sanity checks */
 259         Assert(queryDesc != NULL);
 260
 261         estate = queryDesc->estate;
 262
 263         Assert(estate != NULL);
 264
 265         /*
 266          * Switch into per-query memory context to run ExecEndPlan
 267          */
 268         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 269
 270         ExecEndPlan(queryDesc->planstate, estate);
 271
 272         /*
 273          * Must switch out of context before destroying it
 274          */
 275         MemoryContextSwitchTo(oldcontext);
 276
 277         /*
 278          * Release EState and per-query memory context.  This should release
 279          * everything the executor has allocated.
 280          */
 281         FreeExecutorState(estate);
 282
 283         /* Reset queryDesc fields that no longer point to anything */
 284         queryDesc->tupDesc = NULL;
 285         queryDesc->estate = NULL;
 286         queryDesc->planstate = NULL;
 287 }
 288
 289 /* ----------------------------------------------------------------
 290  *              ExecutorRewind
 291  *
 292  *              This routine may be called on an open queryDesc to rewind it
 293  *              to the start.
 294  * ----------------------------------------------------------------
 295  */
 296 void
 297 ExecutorRewind(QueryDesc *queryDesc)
 298 {
 299         EState     *estate;
 300         MemoryContext oldcontext;
 301
 302         /* sanity checks */
 303         Assert(queryDesc != NULL);
 304
 305         estate = queryDesc->estate;
 306
 307         Assert(estate != NULL);
 308
 309         /* It's probably not sensible to rescan updating queries */
 310         Assert(queryDesc->operation == CMD_SELECT);
 311
 312         /*
 313          * Switch into per-query memory context
 314          */
 315         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 316
 317         /*
 318          * rescan plan
 319          */
 320         ExecReScan(queryDesc->planstate, NULL);
 321
 322         MemoryContextSwitchTo(oldcontext);
 323 }
 324
 325
 326 /*
 327  * ExecCheckRTPerms
 328  *              Check access permissions for all relations listed in a range table.
 329  */
 330 void
 331 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 332 {
 333         List       *lp;
 334
 335         foreach(lp, rangeTable)
 336         {
 337                 RangeTblEntry *rte = lfirst(lp);
 338
 339                 ExecCheckRTEPerms(rte, operation);
 340         }
 341 }
 342
 343 /*
 344  * ExecCheckRTEPerms
 345  *              Check access permissions for a single RTE.
 346  */
 347 static void
 348 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 349 {
 350         Oid                     relOid;
 351         AclId           userid;
 352         AclResult       aclcheck_result;
 353
 354         /*
 355          * If it's a subquery, recursively examine its rangetable.
 356          */
 357         if (rte->rtekind == RTE_SUBQUERY)
 358         {
 359                 ExecCheckRTPerms(rte->subquery->rtable, operation);
 360                 return;
 361         }
 362
 363         /*
 364          * Otherwise, only plain-relation RTEs need to be checked here.
 365          * Function RTEs are checked by init_fcache when the function is prepared
 366          * for execution. Join and special RTEs need no checks.
 367          */
 368         if (rte->rtekind != RTE_RELATION)
 369                 return;
 370
 371         relOid = rte->relid;
 372
 373         /*
 374          * userid to check as: current user unless we have a setuid
 375          * indication.
 376          *
 377          * Note: GetUserId() is presently fast enough that there's no harm in
 378          * calling it separately for each RTE.  If that stops being true, we
 379          * could call it once in ExecCheckRTPerms and pass the userid down
 380          * from there.  But for now, no need for the extra clutter.
 381          */
 382         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 383
 384 #define CHECK(MODE)             pg_class_aclcheck(relOid, userid, MODE)
 385
 386         if (rte->checkForRead)
 387         {
 388                 aclcheck_result = CHECK(ACL_SELECT);
 389                 if (aclcheck_result != ACLCHECK_OK)
 390                         aclcheck_error(aclcheck_result, ACL_KIND_CLASS,
 391                                                    get_rel_name(relOid));
 392         }
 393
 394         if (rte->checkForWrite)
 395         {
 396                 /*
 397                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 398                  * Right now we don't distinguish that from true update as far as
 399                  * permissions checks are concerned.
 400                  */
 401                 switch (operation)
 402                 {
 403                         case CMD_INSERT:
 404                                 aclcheck_result = CHECK(ACL_INSERT);
 405                                 break;
 406                         case CMD_SELECT:
 407                         case CMD_UPDATE:
 408                                 aclcheck_result = CHECK(ACL_UPDATE);
 409                                 break;
 410                         case CMD_DELETE:
 411                                 aclcheck_result = CHECK(ACL_DELETE);
 412                                 break;
 413                         default:
 414                                 elog(ERROR, "unrecognized operation code: %d",
 415                                          (int) operation);
 416                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 417                                 break;
 418                 }
 419                 if (aclcheck_result != ACLCHECK_OK)
 420                         aclcheck_error(aclcheck_result, ACL_KIND_CLASS,
 421                                                    get_rel_name(relOid));
 422         }
 423 }
 424
 425 static void
 426 ExecCheckXactReadOnly(Query *parsetree, CmdType operation)
 427 {
 428         if (!XactReadOnly)
 429                 return;
 430
 431         /* CREATE TABLE AS or SELECT INTO */
 432         if (operation == CMD_SELECT && parsetree->into != NULL)
 433                 goto fail;
 434
 435         if (operation == CMD_DELETE || operation == CMD_INSERT
 436                 || operation == CMD_UPDATE)
 437         {
 438                 List *lp;
 439
 440                 foreach(lp, parsetree->rtable)
 441                 {
 442                         RangeTblEntry *rte = lfirst(lp);
 443
 444                         if (rte->rtekind != RTE_RELATION)
 445                                 continue;
 446
 447                         if (!rte->checkForWrite)
 448                                 continue;
 449
 450                         if (isTempNamespace(get_rel_namespace(rte->relid)))
 451                                 continue;
 452
 453                         goto fail;
 454                 }
 455         }
 456
 457         return;
 458
 459 fail:
 460         ereport(ERROR,
 461                         (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
 462                          errmsg("transaction is read-only")));
 463 }
 464
 465
 466 /* ----------------------------------------------------------------
 467  *              InitPlan
 468  *
 469  *              Initializes the query plan: open files, allocate storage
 470  *              and start up the rule manager
 471  * ----------------------------------------------------------------
 472  */
 473 static void
 474 InitPlan(QueryDesc *queryDesc, bool explainOnly)
 475 {
 476         CmdType         operation = queryDesc->operation;
 477         Query *parseTree = queryDesc->parsetree;
 478         Plan *plan = queryDesc->plantree;
 479         EState *estate = queryDesc->estate;
 480         PlanState  *planstate;
 481         List       *rangeTable;
 482         Relation        intoRelationDesc;
 483         bool            do_select_into;
 484         TupleDesc       tupType;
 485
 486         /*
 487          * Do permissions checks.  It's sufficient to examine the query's
 488          * top rangetable here --- subplan RTEs will be checked during
 489          * ExecInitSubPlan().
 490          */
 491         ExecCheckRTPerms(parseTree->rtable, operation);
 492
 493         /*
 494          * get information from query descriptor
 495          */
 496         rangeTable = parseTree->rtable;
 497
 498         /*
 499          * initialize the node's execution state
 500          */
 501         estate->es_range_table = rangeTable;
 502
 503         /*
 504          * if there is a result relation, initialize result relation stuff
 505          */
 506         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 507         {
 508                 List       *resultRelations = parseTree->resultRelations;
 509                 int                     numResultRelations;
 510                 ResultRelInfo *resultRelInfos;
 511
 512                 if (resultRelations != NIL)
 513                 {
 514                         /*
 515                          * Multiple result relations (due to inheritance)
 516                          * parseTree->resultRelations identifies them all
 517                          */
 518                         ResultRelInfo *resultRelInfo;
 519
 520                         numResultRelations = length(resultRelations);
 521                         resultRelInfos = (ResultRelInfo *)
 522                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 523                         resultRelInfo = resultRelInfos;
 524                         while (resultRelations != NIL)
 525                         {
 526                                 initResultRelInfo(resultRelInfo,
 527                                                                   lfirsti(resultRelations),
 528                                                                   rangeTable,
 529                                                                   operation);
 530                                 resultRelInfo++;
 531                                 resultRelations = lnext(resultRelations);
 532                         }
 533                 }
 534                 else
 535                 {
 536                         /*
 537                          * Single result relation identified by
 538                          * parseTree->resultRelation
 539                          */
 540                         numResultRelations = 1;
 541                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 542                         initResultRelInfo(resultRelInfos,
 543                                                           parseTree->resultRelation,
 544                                                           rangeTable,
 545                                                           operation);
 546                 }
 547
 548                 estate->es_result_relations = resultRelInfos;
 549                 estate->es_num_result_relations = numResultRelations;
 550                 /* Initialize to first or only result rel */
 551                 estate->es_result_relation_info = resultRelInfos;
 552         }
 553         else
 554         {
 555                 /*
 556                  * if no result relation, then set state appropriately
 557                  */
 558                 estate->es_result_relations = NULL;
 559                 estate->es_num_result_relations = 0;
 560                 estate->es_result_relation_info = NULL;
 561         }
 562
 563         /*
 564          * Detect whether we're doing SELECT INTO.  If so, set the force_oids
 565          * flag appropriately so that the plan tree will be initialized with
 566          * the correct tuple descriptors.
 567          */
 568         do_select_into = false;
 569
 570         if (operation == CMD_SELECT && parseTree->into != NULL)
 571         {
 572                 do_select_into = true;
 573                 /*
 574                  * For now, always create OIDs in SELECT INTO; this is for backwards
 575                  * compatibility with pre-7.3 behavior.  Eventually we might want
 576                  * to allow the user to choose.
 577                  */
 578                 estate->es_force_oids = true;
 579         }
 580
 581         /*
 582          * Have to lock relations selected for update
 583          */
 584         estate->es_rowMark = NIL;
 585         if (parseTree->rowMarks != NIL)
 586         {
 587                 List       *l;
 588
 589                 foreach(l, parseTree->rowMarks)
 590                 {
 591                         Index           rti = lfirsti(l);
 592                         Oid                     relid = getrelid(rti, rangeTable);
 593                         Relation        relation;
 594                         execRowMark *erm;
 595
 596                         relation = heap_open(relid, RowShareLock);
 597                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 598                         erm->relation = relation;
 599                         erm->rti = rti;
 600                         snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
 601                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 602                 }
 603         }
 604
 605         /*
 606          * initialize the executor "tuple" table.  We need slots for all the
 607          * plan nodes, plus possibly output slots for the junkfilter(s). At
 608          * this point we aren't sure if we need junkfilters, so just add slots
 609          * for them unconditionally.
 610          */
 611         {
 612                 int                     nSlots = ExecCountSlotsNode(plan);
 613
 614                 if (parseTree->resultRelations != NIL)
 615                         nSlots += length(parseTree->resultRelations);
 616                 else
 617                         nSlots += 1;
 618                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 619         }
 620
 621         /* mark EvalPlanQual not active */
 622         estate->es_topPlan = plan;
 623         estate->es_evalPlanQual = NULL;
 624         estate->es_evTupleNull = NULL;
 625         estate->es_evTuple = NULL;
 626         estate->es_useEvalPlan = false;
 627
 628         /*
 629          * initialize the private state information for all the nodes in the
 630          * query tree.  This opens files, allocates storage and leaves us
 631          * ready to start processing tuples.
 632          */
 633         planstate = ExecInitNode(plan, estate);
 634
 635         /*
 636          * Get the tuple descriptor describing the type of tuples to return.
 637          * (this is especially important if we are creating a relation with
 638          * "SELECT INTO")
 639          */
 640         tupType = ExecGetResultType(planstate);
 641
 642         /*
 643          * Initialize the junk filter if needed.  SELECT and INSERT queries need a
 644          * filter if there are any junk attrs in the tlist.  INSERT and SELECT
 645          * INTO also need a filter if the top plan node is a scan node that's not
 646          * doing projection (else we'll be scribbling on the scan tuple!)  UPDATE
 647          * and DELETE always need a filter, since there's always a junk 'ctid'
 648          * attribute present --- no need to look first.
 649          */
 650         {
 651                 bool            junk_filter_needed = false;
 652                 List       *tlist;
 653
 654                 switch (operation)
 655                 {
 656                         case CMD_SELECT:
 657                         case CMD_INSERT:
 658                                 foreach(tlist, plan->targetlist)
 659                                 {
 660                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 661
 662                                         if (tle->resdom->resjunk)
 663                                         {
 664                                                 junk_filter_needed = true;
 665                                                 break;
 666                                         }
 667                                 }
 668                                 if (!junk_filter_needed &&
 669                                         (operation == CMD_INSERT || do_select_into))
 670                                 {
 671                                         if (IsA(planstate, SeqScanState) ||
 672                                                 IsA(planstate, IndexScanState) ||
 673                                                 IsA(planstate, TidScanState) ||
 674                                                 IsA(planstate, SubqueryScanState) ||
 675                                                 IsA(planstate, FunctionScanState))
 676                                         {
 677                                                 if (planstate->ps_ProjInfo == NULL)
 678                                                         junk_filter_needed = true;
 679                                         }
 680                                 }
 681                                 break;
 682                         case CMD_UPDATE:
 683                         case CMD_DELETE:
 684                                 junk_filter_needed = true;
 685                                 break;
 686                         default:
 687                                 break;
 688                 }
 689
 690                 if (junk_filter_needed)
 691                 {
 692                         /*
 693                          * If there are multiple result relations, each one needs its
 694                          * own junk filter.  Note this is only possible for
 695                          * UPDATE/DELETE, so we can't be fooled by some needing a
 696                          * filter and some not.
 697                          */
 698                         if (parseTree->resultRelations != NIL)
 699                         {
 700                                 PlanState **appendplans;
 701                                 int                     as_nplans;
 702                                 ResultRelInfo *resultRelInfo;
 703                                 int                     i;
 704
 705                                 /* Top plan had better be an Append here. */
 706                                 Assert(IsA(plan, Append));
 707                                 Assert(((Append *) plan)->isTarget);
 708                                 Assert(IsA(planstate, AppendState));
 709                                 appendplans = ((AppendState *) planstate)->appendplans;
 710                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 711                                 Assert(as_nplans == estate->es_num_result_relations);
 712                                 resultRelInfo = estate->es_result_relations;
 713                                 for (i = 0; i < as_nplans; i++)
 714                                 {
 715                                         PlanState  *subplan = appendplans[i];
 716                                         JunkFilter *j;
 717
 718                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 719                                                                                    ExecGetResultType(subplan),
 720                                                           ExecAllocTableSlot(estate->es_tupleTable));
 721                                         resultRelInfo->ri_junkFilter = j;
 722                                         resultRelInfo++;
 723                                 }
 724
 725                                 /*
 726                                  * Set active junkfilter too; at this point ExecInitAppend
 727                                  * has already selected an active result relation...
 728                                  */
 729                                 estate->es_junkFilter =
 730                                         estate->es_result_relation_info->ri_junkFilter;
 731                         }
 732                         else
 733                         {
 734                                 /* Normal case with just one JunkFilter */
 735                                 JunkFilter *j;
 736
 737                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 738                                                                            tupType,
 739                                                           ExecAllocTableSlot(estate->es_tupleTable));
 740                                 estate->es_junkFilter = j;
 741                                 if (estate->es_result_relation_info)
 742                                         estate->es_result_relation_info->ri_junkFilter = j;
 743
 744                                 /* For SELECT, want to return the cleaned tuple type */
 745                                 if (operation == CMD_SELECT)
 746                                         tupType = j->jf_cleanTupType;
 747                         }
 748                 }
 749                 else
 750                         estate->es_junkFilter = NULL;
 751         }
 752
 753         /*
 754          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 755          * till now so we have the "clean" result tuple type to create the
 756          * new table from.
 757          *
 758          * If EXPLAIN, skip creating the "into" relation.
 759          */
 760         intoRelationDesc = (Relation) NULL;
 761
 762         if (do_select_into && !explainOnly)
 763         {
 764                 char       *intoName;
 765                 Oid                     namespaceId;
 766                 AclResult       aclresult;
 767                 Oid                     intoRelationId;
 768                 TupleDesc       tupdesc;
 769
 770                 /*
 771                  * find namespace to create in, check permissions
 772                  */
 773                 intoName = parseTree->into->relname;
 774                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 775
 776                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 777                                                                                   ACL_CREATE);
 778                 if (aclresult != ACLCHECK_OK)
 779                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 780                                                    get_namespace_name(namespaceId));
 781
 782                 /*
 783                  * have to copy tupType to get rid of constraints
 784                  */
 785                 tupdesc = CreateTupleDescCopy(tupType);
 786
 787                 intoRelationId = heap_create_with_catalog(intoName,
 788                                                                                                   namespaceId,
 789                                                                                                   tupdesc,
 790                                                                                                   RELKIND_RELATION,
 791                                                                                                   false,
 792                                                                                                   ONCOMMIT_NOOP,
 793                                                                                                   allowSystemTableMods);
 794
 795                 FreeTupleDesc(tupdesc);
 796
 797                 /*
 798                  * Advance command counter so that the newly-created
 799                  * relation's catalog tuples will be visible to heap_open.
 800                  */
 801                 CommandCounterIncrement();
 802
 803                 /*
 804                  * If necessary, create a TOAST table for the into
 805                  * relation. Note that AlterTableCreateToastTable ends
 806                  * with CommandCounterIncrement(), so that the TOAST table
 807                  * will be visible for insertion.
 808                  */
 809                 AlterTableCreateToastTable(intoRelationId, true);
 810
 811                 /*
 812                  * And open the constructed table for writing.
 813                  */
 814                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 815         }
 816
 817         estate->es_into_relation_descriptor = intoRelationDesc;
 818
 819         queryDesc->tupDesc = tupType;
 820         queryDesc->planstate = planstate;
 821 }
 822
 823 /*
 824  * Initialize ResultRelInfo data for one result relation
 825  */
 826 static void
 827 initResultRelInfo(ResultRelInfo *resultRelInfo,
 828                                   Index resultRelationIndex,
 829                                   List *rangeTable,
 830                                   CmdType operation)
 831 {
 832         Oid                     resultRelationOid;
 833         Relation        resultRelationDesc;
 834
 835         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 836         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 837
 838         switch (resultRelationDesc->rd_rel->relkind)
 839         {
 840                 case RELKIND_SEQUENCE:
 841                         ereport(ERROR,
 842                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 843                                          errmsg("cannot change sequence relation \"%s\"",
 844                                                         RelationGetRelationName(resultRelationDesc))));
 845                         break;
 846                 case RELKIND_TOASTVALUE:
 847                         ereport(ERROR,
 848                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 849                                          errmsg("cannot change toast relation \"%s\"",
 850                                                         RelationGetRelationName(resultRelationDesc))));
 851                         break;
 852                 case RELKIND_VIEW:
 853                         ereport(ERROR,
 854                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 855                                          errmsg("cannot change view relation \"%s\"",
 856                                                         RelationGetRelationName(resultRelationDesc))));
 857                         break;
 858         }
 859
 860         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 861         resultRelInfo->type = T_ResultRelInfo;
 862         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 863         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 864         resultRelInfo->ri_NumIndices = 0;
 865         resultRelInfo->ri_IndexRelationDescs = NULL;
 866         resultRelInfo->ri_IndexRelationInfo = NULL;
 867         /* make a copy so as not to depend on relcache info not changing... */
 868         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 869         resultRelInfo->ri_TrigFunctions = NULL;
 870         resultRelInfo->ri_ConstraintExprs = NULL;
 871         resultRelInfo->ri_junkFilter = NULL;
 872
 873         /*
 874          * If there are indices on the result relation, open them and save
 875          * descriptors in the result relation info, so that we can add new
 876          * index entries for the tuples we add/update.  We need not do this
 877          * for a DELETE, however, since deletion doesn't affect indexes.
 878          */
 879         if (resultRelationDesc->rd_rel->relhasindex &&
 880                 operation != CMD_DELETE)
 881                 ExecOpenIndices(resultRelInfo);
 882 }
 883
 884 /* ----------------------------------------------------------------
 885  *              ExecEndPlan
 886  *
 887  *              Cleans up the query plan -- closes files and frees up storage
 888  *
 889  * NOTE: we are no longer very worried about freeing storage per se
 890  * in this code; FreeExecutorState should be guaranteed to release all
 891  * memory that needs to be released.  What we are worried about doing
 892  * is closing relations and dropping buffer pins.  Thus, for example,
 893  * tuple tables must be cleared or dropped to ensure pins are released.
 894  * ----------------------------------------------------------------
 895  */
 896 void
 897 ExecEndPlan(PlanState *planstate, EState *estate)
 898 {
 899         ResultRelInfo *resultRelInfo;
 900         int                     i;
 901         List       *l;
 902
 903         /*
 904          * shut down any PlanQual processing we were doing
 905          */
 906         if (estate->es_evalPlanQual != NULL)
 907                 EndEvalPlanQual(estate);
 908
 909         /*
 910          * shut down the node-type-specific query processing
 911          */
 912         ExecEndNode(planstate);
 913
 914         /*
 915          * destroy the executor "tuple" table.
 916          */
 917         ExecDropTupleTable(estate->es_tupleTable, true);
 918         estate->es_tupleTable = NULL;
 919
 920         /*
 921          * close the result relation(s) if any, but hold locks until xact
 922          * commit.
 923          */
 924         resultRelInfo = estate->es_result_relations;
 925         for (i = estate->es_num_result_relations; i > 0; i--)
 926         {
 927                 /* Close indices and then the relation itself */
 928                 ExecCloseIndices(resultRelInfo);
 929                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 930                 resultRelInfo++;
 931         }
 932
 933         /*
 934          * close the "into" relation if necessary, again keeping lock
 935          */
 936         if (estate->es_into_relation_descriptor != NULL)
 937                 heap_close(estate->es_into_relation_descriptor, NoLock);
 938
 939         /*
 940          * close any relations selected FOR UPDATE, again keeping locks
 941          */
 942         foreach(l, estate->es_rowMark)
 943         {
 944                 execRowMark *erm = lfirst(l);
 945
 946                 heap_close(erm->relation, NoLock);
 947         }
 948 }
 949
 950 /* ----------------------------------------------------------------
 951  *              ExecutePlan
 952  *
 953  *              processes the query plan to retrieve 'numberTuples' tuples in the
 954  *              direction specified.
 955  *
 956  *              Retrieves all tuples if numberTuples is 0
 957  *
 958  *              result is either a slot containing the last tuple in the case
 959  *              of a SELECT or NULL otherwise.
 960  *
 961  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 962  * user can see it
 963  * ----------------------------------------------------------------
 964  */
 965 static TupleTableSlot *
 966 ExecutePlan(EState *estate,
 967                         PlanState *planstate,
 968                         CmdType operation,
 969                         long numberTuples,
 970                         ScanDirection direction,
 971                         DestReceiver *dest)
 972 {
 973         JunkFilter                      *junkfilter;
 974         TupleTableSlot          *slot;
 975         ItemPointer                      tupleid = NULL;
 976         ItemPointerData          tuple_ctid;
 977         long                             current_tuple_count;
 978         TupleTableSlot          *result;
 979
 980         /*
 981          * initialize local variables
 982          */
 983         slot = NULL;
 984         current_tuple_count = 0;
 985         result = NULL;
 986
 987         /*
 988          * Set the direction.
 989          */
 990         estate->es_direction = direction;
 991
 992         /*
 993          * Process BEFORE EACH STATEMENT triggers
 994          */
 995         switch (operation)
 996         {
 997                 case CMD_UPDATE:
 998                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
 999                         break;
1000                 case CMD_DELETE:
1001                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1002                         break;
1003                 case CMD_INSERT:
1004                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1005                         break;
1006                 default:
1007                         /* do nothing */
1008                         break;
1009         }
1010
1011         /*
1012          * Loop until we've processed the proper number of tuples from the
1013          * plan.
1014          */
1015
1016         for (;;)
1017         {
1018                 /* Reset the per-output-tuple exprcontext */
1019                 ResetPerTupleExprContext(estate);
1020
1021                 /*
1022                  * Execute the plan and obtain a tuple
1023                  */
1024 lnext:  ;
1025                 if (estate->es_useEvalPlan)
1026                 {
1027                         slot = EvalPlanQualNext(estate);
1028                         if (TupIsNull(slot))
1029                                 slot = ExecProcNode(planstate);
1030                 }
1031                 else
1032                         slot = ExecProcNode(planstate);
1033
1034                 /*
1035                  * if the tuple is null, then we assume there is nothing more to
1036                  * process so we just return null...
1037                  */
1038                 if (TupIsNull(slot))
1039                 {
1040                         result = NULL;
1041                         break;
1042                 }
1043
1044                 /*
1045                  * if we have a junk filter, then project a new tuple with the
1046                  * junk removed.
1047                  *
1048                  * Store this new "clean" tuple in the junkfilter's resultSlot.
1049                  * (Formerly, we stored it back over the "dirty" tuple, which is
1050                  * WRONG because that tuple slot has the wrong descriptor.)
1051                  *
1052                  * Also, extract all the junk information we need.
1053                  */
1054                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
1055                 {
1056                         Datum           datum;
1057                         HeapTuple       newTuple;
1058                         bool            isNull;
1059
1060                         /*
1061                          * extract the 'ctid' junk attribute.
1062                          */
1063                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1064                         {
1065                                 if (!ExecGetJunkAttribute(junkfilter,
1066                                                                                   slot,
1067                                                                                   "ctid",
1068                                                                                   &datum,
1069                                                                                   &isNull))
1070                                         elog(ERROR, "could not find junk ctid column");
1071
1072                                 /* shouldn't ever get a null result... */
1073                                 if (isNull)
1074                                         elog(ERROR, "ctid is NULL");
1075
1076                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1077                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1078                                                                                  * ctid!! */
1079                                 tupleid = &tuple_ctid;
1080                         }
1081                         else if (estate->es_rowMark != NIL)
1082                         {
1083                                 List       *l;
1084
1085                 lmark:  ;
1086                                 foreach(l, estate->es_rowMark)
1087                                 {
1088                                         execRowMark *erm = lfirst(l);
1089                                         Buffer          buffer;
1090                                         HeapTupleData tuple;
1091                                         TupleTableSlot *newSlot;
1092                                         int                     test;
1093
1094                                         if (!ExecGetJunkAttribute(junkfilter,
1095                                                                                           slot,
1096                                                                                           erm->resname,
1097                                                                                           &datum,
1098                                                                                           &isNull))
1099                                                 elog(ERROR, "could not find junk \"%s\" column",
1100                                                          erm->resname);
1101
1102                                         /* shouldn't ever get a null result... */
1103                                         if (isNull)
1104                                                 elog(ERROR, "\"%s\" is NULL", erm->resname);
1105
1106                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1107                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1108                                                                                         estate->es_snapshot->curcid);
1109                                         ReleaseBuffer(buffer);
1110                                         switch (test)
1111                                         {
1112                                                 case HeapTupleSelfUpdated:
1113                                                         /* treat it as deleted; do not process */
1114                                                         goto lnext;
1115
1116                                                 case HeapTupleMayBeUpdated:
1117                                                         break;
1118
1119                                                 case HeapTupleUpdated:
1120                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1121                                                                 ereport(ERROR,
1122                                                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1123                                                                                  errmsg("could not serialize access due to concurrent update")));
1124                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1125                                                                   (ItemPointer) DatumGetPointer(datum))))
1126                                                         {
1127                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1128                                                                 if (!(TupIsNull(newSlot)))
1129                                                                 {
1130                                                                         slot = newSlot;
1131                                                                         estate->es_useEvalPlan = true;
1132                                                                         goto lmark;
1133                                                                 }
1134                                                         }
1135
1136                                                         /*
1137                                                          * if tuple was deleted or PlanQual failed for
1138                                                          * updated tuple - we must not return this
1139                                                          * tuple!
1140                                                          */
1141                                                         goto lnext;
1142
1143                                                 default:
1144                                                         elog(ERROR, "unrecognized heap_mark4update status: %u",
1145                                                                  test);
1146                                                         return (NULL);
1147                                         }
1148                                 }
1149                         }
1150
1151                         /*
1152                          * Finally create a new "clean" tuple with all junk attributes
1153                          * removed
1154                          */
1155                         newTuple = ExecRemoveJunk(junkfilter, slot);
1156
1157                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1158                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1159                                                                   InvalidBuffer,                /* this tuple has no
1160                                                                                                                  * buffer */
1161                                                                   true);                /* tuple should be pfreed */
1162                 }
1163
1164                 /*
1165                  * now that we have a tuple, do the appropriate thing with it..
1166                  * either return it to the user, add it to a relation someplace,
1167                  * delete it from a relation, or modify some of its attributes.
1168                  */
1169                 switch (operation)
1170                 {
1171                         case CMD_SELECT:
1172                                 ExecSelect(slot,        /* slot containing tuple */
1173                                                    dest,        /* destination's tuple-receiver obj */
1174                                                    estate);
1175                                 result = slot;
1176                                 break;
1177
1178                         case CMD_INSERT:
1179                                 ExecInsert(slot, tupleid, estate);
1180                                 result = NULL;
1181                                 break;
1182
1183                         case CMD_DELETE:
1184                                 ExecDelete(slot, tupleid, estate);
1185                                 result = NULL;
1186                                 break;
1187
1188                         case CMD_UPDATE:
1189                                 ExecUpdate(slot, tupleid, estate);
1190                                 result = NULL;
1191                                 break;
1192
1193                         default:
1194                                 elog(ERROR, "unrecognized operation code: %d",
1195                                          (int) operation);
1196                                 result = NULL;
1197                                 break;
1198                 }
1199
1200                 /*
1201                  * check our tuple count.. if we've processed the proper number
1202                  * then quit, else loop again and process more tuples.  Zero
1203                  * numberTuples means no limit.
1204                  */
1205                 current_tuple_count++;
1206                 if (numberTuples && numberTuples == current_tuple_count)
1207                         break;
1208         }
1209
1210         /*
1211          * Process AFTER EACH STATEMENT triggers
1212          */
1213         switch (operation)
1214         {
1215                 case CMD_UPDATE:
1216                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1217                         break;
1218                 case CMD_DELETE:
1219                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1220                         break;
1221                 case CMD_INSERT:
1222                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1223                         break;
1224                 default:
1225                         /* do nothing */
1226                         break;
1227         }
1228
1229         /*
1230          * here, result is either a slot containing a tuple in the case of a
1231          * SELECT or NULL otherwise.
1232          */
1233         return result;
1234 }
1235
1236 /* ----------------------------------------------------------------
1237  *              ExecSelect
1238  *
1239  *              SELECTs are easy.. we just pass the tuple to the appropriate
1240  *              print function.  The only complexity is when we do a
1241  *              "SELECT INTO", in which case we insert the tuple into
1242  *              the appropriate relation (note: this is a newly created relation
1243  *              so we don't need to worry about indices or locks.)
1244  * ----------------------------------------------------------------
1245  */
1246 static void
1247 ExecSelect(TupleTableSlot *slot,
1248                    DestReceiver *dest,
1249                    EState *estate)
1250 {
1251         HeapTuple       tuple;
1252         TupleDesc       attrtype;
1253
1254         /*
1255          * get the heap tuple out of the tuple table slot
1256          */
1257         tuple = slot->val;
1258         attrtype = slot->ttc_tupleDescriptor;
1259
1260         /*
1261          * insert the tuple into the "into relation"
1262          *
1263          * XXX this probably ought to be replaced by a separate destination
1264          */
1265         if (estate->es_into_relation_descriptor != NULL)
1266         {
1267                 heap_insert(estate->es_into_relation_descriptor, tuple,
1268                                         estate->es_snapshot->curcid);
1269                 IncrAppended();
1270         }
1271
1272         /*
1273          * send the tuple to the destination
1274          */
1275         (*dest->receiveTuple) (tuple, attrtype, dest);
1276         IncrRetrieved();
1277         (estate->es_processed)++;
1278 }
1279
1280 /* ----------------------------------------------------------------
1281  *              ExecInsert
1282  *
1283  *              INSERTs are trickier.. we have to insert the tuple into
1284  *              the base relation and insert appropriate tuples into the
1285  *              index relations.
1286  * ----------------------------------------------------------------
1287  */
1288 static void
1289 ExecInsert(TupleTableSlot *slot,
1290                    ItemPointer tupleid,
1291                    EState *estate)
1292 {
1293         HeapTuple       tuple;
1294         ResultRelInfo *resultRelInfo;
1295         Relation        resultRelationDesc;
1296         int                     numIndices;
1297         Oid                     newId;
1298
1299         /*
1300          * get the heap tuple out of the tuple table slot
1301          */
1302         tuple = slot->val;
1303
1304         /*
1305          * get information on the (current) result relation
1306          */
1307         resultRelInfo = estate->es_result_relation_info;
1308         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1309
1310         /* BEFORE ROW INSERT Triggers */
1311         if (resultRelInfo->ri_TrigDesc &&
1312                 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1313         {
1314                 HeapTuple       newtuple;
1315
1316                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1317
1318                 if (newtuple == NULL)   /* "do nothing" */
1319                         return;
1320
1321                 if (newtuple != tuple)  /* modified by Trigger(s) */
1322                 {
1323                         /*
1324                          * Insert modified tuple into tuple table slot, replacing the
1325                          * original.  We assume that it was allocated in per-tuple
1326                          * memory context, and therefore will go away by itself. The
1327                          * tuple table slot should not try to clear it.
1328                          */
1329                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1330                         tuple = newtuple;
1331                 }
1332         }
1333
1334         /*
1335          * Check the constraints of the tuple
1336          */
1337         if (resultRelationDesc->rd_att->constr)
1338                 ExecConstraints(resultRelInfo, slot, estate);
1339
1340         /*
1341          * insert the tuple
1342          */
1343         newId = heap_insert(resultRelationDesc, tuple,
1344                                                 estate->es_snapshot->curcid);
1345
1346         IncrAppended();
1347         (estate->es_processed)++;
1348         estate->es_lastoid = newId;
1349         setLastTid(&(tuple->t_self));
1350
1351         /*
1352          * process indices
1353          *
1354          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1355          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1356          * field.
1357          */
1358         numIndices = resultRelInfo->ri_NumIndices;
1359         if (numIndices > 0)
1360                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1361
1362         /* AFTER ROW INSERT Triggers */
1363         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1364 }
1365
1366 /* ----------------------------------------------------------------
1367  *              ExecDelete
1368  *
1369  *              DELETE is like UPDATE, we delete the tuple and its
1370  *              index tuples.
1371  * ----------------------------------------------------------------
1372  */
1373 static void
1374 ExecDelete(TupleTableSlot *slot,
1375                    ItemPointer tupleid,
1376                    EState *estate)
1377 {
1378         ResultRelInfo *resultRelInfo;
1379         Relation        resultRelationDesc;
1380         ItemPointerData ctid;
1381         int                     result;
1382
1383         /*
1384          * get information on the (current) result relation
1385          */
1386         resultRelInfo = estate->es_result_relation_info;
1387         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1388
1389         /* BEFORE ROW DELETE Triggers */
1390         if (resultRelInfo->ri_TrigDesc &&
1391           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1392         {
1393                 bool            dodelete;
1394
1395                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1396                                                                                 estate->es_snapshot->curcid);
1397
1398                 if (!dodelete)                  /* "do nothing" */
1399                         return;
1400         }
1401
1402         /*
1403          * delete the tuple
1404          */
1405 ldelete:;
1406         result = heap_delete(resultRelationDesc, tupleid,
1407                                                  &ctid,
1408                                                  estate->es_snapshot->curcid);
1409         switch (result)
1410         {
1411                 case HeapTupleSelfUpdated:
1412                         /* already deleted by self; nothing to do */
1413                         return;
1414
1415                 case HeapTupleMayBeUpdated:
1416                         break;
1417
1418                 case HeapTupleUpdated:
1419                         if (XactIsoLevel == XACT_SERIALIZABLE)
1420                                 ereport(ERROR,
1421                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1422                                                  errmsg("could not serialize access due to concurrent update")));
1423                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1424                         {
1425                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1426                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1427
1428                                 if (!TupIsNull(epqslot))
1429                                 {
1430                                         *tupleid = ctid;
1431                                         goto ldelete;
1432                                 }
1433                         }
1434                         /* tuple already deleted; nothing to do */
1435                         return;
1436
1437                 default:
1438                         elog(ERROR, "unrecognized heap_delete status: %u", result);
1439                         return;
1440         }
1441
1442         IncrDeleted();
1443         (estate->es_processed)++;
1444
1445         /*
1446          * Note: Normally one would think that we have to delete index tuples
1447          * associated with the heap tuple now..
1448          *
1449          * ... but in POSTGRES, we have no need to do this because the vacuum
1450          * daemon automatically opens an index scan and deletes index tuples
1451          * when it finds deleted heap tuples. -cim 9/27/89
1452          */
1453
1454         /* AFTER ROW DELETE Triggers */
1455         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1456 }
1457
1458 /* ----------------------------------------------------------------
1459  *              ExecUpdate
1460  *
1461  *              note: we can't run UPDATE queries with transactions
1462  *              off because UPDATEs are actually INSERTs and our
1463  *              scan will mistakenly loop forever, updating the tuple
1464  *              it just inserted..      This should be fixed but until it
1465  *              is, we don't want to get stuck in an infinite loop
1466  *              which corrupts your database..
1467  * ----------------------------------------------------------------
1468  */
1469 static void
1470 ExecUpdate(TupleTableSlot *slot,
1471                    ItemPointer tupleid,
1472                    EState *estate)
1473 {
1474         HeapTuple       tuple;
1475         ResultRelInfo *resultRelInfo;
1476         Relation        resultRelationDesc;
1477         ItemPointerData ctid;
1478         int                     result;
1479         int                     numIndices;
1480
1481         /*
1482          * abort the operation if not running transactions
1483          */
1484         if (IsBootstrapProcessingMode())
1485                 elog(ERROR, "cannot UPDATE during bootstrap");
1486
1487         /*
1488          * get the heap tuple out of the tuple table slot
1489          */
1490         tuple = slot->val;
1491
1492         /*
1493          * get information on the (current) result relation
1494          */
1495         resultRelInfo = estate->es_result_relation_info;
1496         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1497
1498         /* BEFORE ROW UPDATE Triggers */
1499         if (resultRelInfo->ri_TrigDesc &&
1500           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1501         {
1502                 HeapTuple       newtuple;
1503
1504                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1505                                                                                 tupleid, tuple,
1506                                                                                 estate->es_snapshot->curcid);
1507
1508                 if (newtuple == NULL)   /* "do nothing" */
1509                         return;
1510
1511                 if (newtuple != tuple)  /* modified by Trigger(s) */
1512                 {
1513                         /*
1514                          * Insert modified tuple into tuple table slot, replacing the
1515                          * original.  We assume that it was allocated in per-tuple
1516                          * memory context, and therefore will go away by itself. The
1517                          * tuple table slot should not try to clear it.
1518                          */
1519                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1520                         tuple = newtuple;
1521                 }
1522         }
1523
1524         /*
1525          * Check the constraints of the tuple
1526          *
1527          * If we generate a new candidate tuple after EvalPlanQual testing, we
1528          * must loop back here and recheck constraints.  (We don't need to
1529          * redo triggers, however.      If there are any BEFORE triggers then
1530          * trigger.c will have done mark4update to lock the correct tuple, so
1531          * there's no need to do them again.)
1532          */
1533 lreplace:;
1534         if (resultRelationDesc->rd_att->constr)
1535                 ExecConstraints(resultRelInfo, slot, estate);
1536
1537         /*
1538          * replace the heap tuple
1539          */
1540         result = heap_update(resultRelationDesc, tupleid, tuple,
1541                                                  &ctid,
1542                                                  estate->es_snapshot->curcid);
1543         switch (result)
1544         {
1545                 case HeapTupleSelfUpdated:
1546                         /* already deleted by self; nothing to do */
1547                         return;
1548
1549                 case HeapTupleMayBeUpdated:
1550                         break;
1551
1552                 case HeapTupleUpdated:
1553                         if (XactIsoLevel == XACT_SERIALIZABLE)
1554                                 ereport(ERROR,
1555                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1556                                                  errmsg("could not serialize access due to concurrent update")));
1557                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1558                         {
1559                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1560                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1561
1562                                 if (!TupIsNull(epqslot))
1563                                 {
1564                                         *tupleid = ctid;
1565                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1566                                         slot = ExecStoreTuple(tuple,
1567                                                                         estate->es_junkFilter->jf_resultSlot,
1568                                                                                   InvalidBuffer, true);
1569                                         goto lreplace;
1570                                 }
1571                         }
1572                         /* tuple already deleted; nothing to do */
1573                         return;
1574
1575                 default:
1576                         elog(ERROR, "unrecognized heap_update status: %u", result);
1577                         return;
1578         }
1579
1580         IncrReplaced();
1581         (estate->es_processed)++;
1582
1583         /*
1584          * Note: instead of having to update the old index tuples associated
1585          * with the heap tuple, all we do is form and insert new index tuples.
1586          * This is because UPDATEs are actually DELETEs and INSERTs and index
1587          * tuple deletion is done automagically by the vacuum daemon. All we
1588          * do is insert new index tuples.  -cim 9/27/89
1589          */
1590
1591         /*
1592          * process indices
1593          *
1594          * heap_update updates a tuple in the base relation by invalidating it
1595          * and then inserting a new tuple to the relation.      As a side effect,
1596          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1597          * field.  So we now insert index tuples using the new tupleid stored
1598          * there.
1599          */
1600
1601         numIndices = resultRelInfo->ri_NumIndices;
1602         if (numIndices > 0)
1603                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1604
1605         /* AFTER ROW UPDATE Triggers */
1606         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1607 }
1608
1609 static const char *
1610 ExecRelCheck(ResultRelInfo *resultRelInfo,
1611                          TupleTableSlot *slot, EState *estate)
1612 {
1613         Relation        rel = resultRelInfo->ri_RelationDesc;
1614         int                     ncheck = rel->rd_att->constr->num_check;
1615         ConstrCheck *check = rel->rd_att->constr->check;
1616         ExprContext *econtext;
1617         MemoryContext oldContext;
1618         List       *qual;
1619         int                     i;
1620
1621         /*
1622          * If first time through for this result relation, build expression
1623          * nodetrees for rel's constraint expressions.  Keep them in the
1624          * per-query memory context so they'll survive throughout the query.
1625          */
1626         if (resultRelInfo->ri_ConstraintExprs == NULL)
1627         {
1628                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1629                 resultRelInfo->ri_ConstraintExprs =
1630                         (List **) palloc(ncheck * sizeof(List *));
1631                 for (i = 0; i < ncheck; i++)
1632                 {
1633                         qual = (List *) stringToNode(check[i].ccbin);
1634                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1635                                 ExecPrepareExpr((Expr *) qual, estate);
1636                 }
1637                 MemoryContextSwitchTo(oldContext);
1638         }
1639
1640         /*
1641          * We will use the EState's per-tuple context for evaluating
1642          * constraint expressions (creating it if it's not already there).
1643          */
1644         econtext = GetPerTupleExprContext(estate);
1645
1646         /* Arrange for econtext's scan tuple to be the tuple under test */
1647         econtext->ecxt_scantuple = slot;
1648
1649         /* And evaluate the constraints */
1650         for (i = 0; i < ncheck; i++)
1651         {
1652                 qual = resultRelInfo->ri_ConstraintExprs[i];
1653
1654                 /*
1655                  * NOTE: SQL92 specifies that a NULL result from a constraint
1656                  * expression is not to be treated as a failure.  Therefore, tell
1657                  * ExecQual to return TRUE for NULL.
1658                  */
1659                 if (!ExecQual(qual, econtext, true))
1660                         return check[i].ccname;
1661         }
1662
1663         /* NULL result means no error */
1664         return NULL;
1665 }
1666
1667 void
1668 ExecConstraints(ResultRelInfo *resultRelInfo,
1669                                 TupleTableSlot *slot, EState *estate)
1670 {
1671         Relation        rel = resultRelInfo->ri_RelationDesc;
1672         HeapTuple       tuple = slot->val;
1673         TupleConstr *constr = rel->rd_att->constr;
1674
1675         Assert(constr);
1676
1677         if (constr->has_not_null)
1678         {
1679                 int                     natts = rel->rd_att->natts;
1680                 int                     attrChk;
1681
1682                 for (attrChk = 1; attrChk <= natts; attrChk++)
1683                 {
1684                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1685                                 heap_attisnull(tuple, attrChk))
1686                                 ereport(ERROR,
1687                                                 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1688                                                  errmsg("null value for attribute \"%s\" violates NOT NULL constraint",
1689                                                                 NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1690                 }
1691         }
1692
1693         if (constr->num_check > 0)
1694         {
1695                 const char         *failed;
1696
1697                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1698                         ereport(ERROR,
1699                                         (errcode(ERRCODE_CHECK_VIOLATION),
1700                                          errmsg("new row for relation \"%s\" violates CHECK constraint \"%s\"",
1701                                                         RelationGetRelationName(rel), failed)));
1702         }
1703 }
1704
1705 /*
1706  * Check a modified tuple to see if we want to process its updated version
1707  * under READ COMMITTED rules.
1708  *
1709  * See backend/executor/README for some info about how this works.
1710  */
1711 TupleTableSlot *
1712 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1713 {
1714         evalPlanQual *epq;
1715         EState     *epqstate;
1716         Relation        relation;
1717         HeapTupleData tuple;
1718         HeapTuple       copyTuple = NULL;
1719         bool            endNode;
1720
1721         Assert(rti != 0);
1722
1723         /*
1724          * find relation containing target tuple
1725          */
1726         if (estate->es_result_relation_info != NULL &&
1727                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1728                 relation = estate->es_result_relation_info->ri_RelationDesc;
1729         else
1730         {
1731                 List       *l;
1732
1733                 relation = NULL;
1734                 foreach(l, estate->es_rowMark)
1735                 {
1736                         if (((execRowMark *) lfirst(l))->rti == rti)
1737                         {
1738                                 relation = ((execRowMark *) lfirst(l))->relation;
1739                                 break;
1740                         }
1741                 }
1742                 if (relation == NULL)
1743                         elog(ERROR, "could not find RowMark for RT index %u", rti);
1744         }
1745
1746         /*
1747          * fetch tid tuple
1748          *
1749          * Loop here to deal with updated or busy tuples
1750          */
1751         tuple.t_self = *tid;
1752         for (;;)
1753         {
1754                 Buffer          buffer;
1755
1756                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1757                 {
1758                         TransactionId xwait = SnapshotDirty->xmax;
1759
1760                         /* xmin should not be dirty... */
1761                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1762                                 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1763
1764                         /*
1765                          * If tuple is being updated by other transaction then we have
1766                          * to wait for its commit/abort.
1767                          */
1768                         if (TransactionIdIsValid(xwait))
1769                         {
1770                                 ReleaseBuffer(buffer);
1771                                 XactLockTableWait(xwait);
1772                                 continue;
1773                         }
1774
1775                         /*
1776                          * We got tuple - now copy it for use by recheck query.
1777                          */
1778                         copyTuple = heap_copytuple(&tuple);
1779                         ReleaseBuffer(buffer);
1780                         break;
1781                 }
1782
1783                 /*
1784                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1785                  * Note that it's possible to get invalid SnapshotDirty->tid if
1786                  * tuple updated by this transaction. Have we to check this ?
1787                  */
1788                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1789                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1790                 {
1791                         /* updated, so look at the updated copy */
1792                         tuple.t_self = SnapshotDirty->tid;
1793                         continue;
1794                 }
1795
1796                 /*
1797                  * Deleted or updated by this transaction; forget it.
1798                  */
1799                 return NULL;
1800         }
1801
1802         /*
1803          * For UPDATE/DELETE we have to return tid of actual row we're
1804          * executing PQ for.
1805          */
1806         *tid = tuple.t_self;
1807
1808         /*
1809          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1810          */
1811         epq = estate->es_evalPlanQual;
1812         endNode = true;
1813
1814         if (epq != NULL && epq->rti == 0)
1815         {
1816                 /* Top PQ stack entry is idle, so re-use it */
1817                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1818                 epq->rti = rti;
1819                 endNode = false;
1820         }
1821
1822         /*
1823          * If this is request for another RTE - Ra, - then we have to check
1824          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1825          * updated again and we have to re-start old execution for Ra and
1826          * forget all what we done after Ra was suspended. Cool? -:))
1827          */
1828         if (epq != NULL && epq->rti != rti &&
1829                 epq->estate->es_evTuple[rti - 1] != NULL)
1830         {
1831                 do
1832                 {
1833                         evalPlanQual *oldepq;
1834
1835                         /* stop execution */
1836                         EvalPlanQualStop(epq);
1837                         /* pop previous PlanQual from the stack */
1838                         oldepq = epq->next;
1839                         Assert(oldepq && oldepq->rti != 0);
1840                         /* push current PQ to freePQ stack */
1841                         oldepq->free = epq;
1842                         epq = oldepq;
1843                         estate->es_evalPlanQual = epq;
1844                 } while (epq->rti != rti);
1845         }
1846
1847         /*
1848          * If we are requested for another RTE then we have to suspend
1849          * execution of current PlanQual and start execution for new one.
1850          */
1851         if (epq == NULL || epq->rti != rti)
1852         {
1853                 /* try to reuse plan used previously */
1854                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1855
1856                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1857                 {
1858                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1859                         newepq->free = NULL;
1860                         newepq->estate = NULL;
1861                         newepq->planstate = NULL;
1862                 }
1863                 else
1864                 {
1865                         /* recycle previously used PlanQual */
1866                         Assert(newepq->estate == NULL);
1867                         epq->free = NULL;
1868                 }
1869                 /* push current PQ to the stack */
1870                 newepq->next = epq;
1871                 epq = newepq;
1872                 estate->es_evalPlanQual = epq;
1873                 epq->rti = rti;
1874                 endNode = false;
1875         }
1876
1877         Assert(epq->rti == rti);
1878
1879         /*
1880          * Ok - we're requested for the same RTE.  Unfortunately we still have
1881          * to end and restart execution of the plan, because ExecReScan
1882          * wouldn't ensure that upper plan nodes would reset themselves.  We
1883          * could make that work if insertion of the target tuple were
1884          * integrated with the Param mechanism somehow, so that the upper plan
1885          * nodes know that their children's outputs have changed.
1886          *
1887          * Note that the stack of free evalPlanQual nodes is quite useless at
1888          * the moment, since it only saves us from pallocing/releasing the
1889          * evalPlanQual nodes themselves.  But it will be useful once we
1890          * implement ReScan instead of end/restart for re-using PlanQual nodes.
1891          */
1892         if (endNode)
1893         {
1894                 /* stop execution */
1895                 EvalPlanQualStop(epq);
1896         }
1897
1898         /*
1899          * Initialize new recheck query.
1900          *
1901          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need
1902          * to instead copy down changeable state from the top plan (including
1903          * es_result_relation_info, es_junkFilter) and reset locally changeable
1904          * state in the epq (including es_param_exec_vals, es_evTupleNull).
1905          */
1906         EvalPlanQualStart(epq, estate, epq->next);
1907
1908         /*
1909          * free old RTE' tuple, if any, and store target tuple where
1910          * relation's scan node will see it
1911          */
1912         epqstate = epq->estate;
1913         if (epqstate->es_evTuple[rti - 1] != NULL)
1914                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1915         epqstate->es_evTuple[rti - 1] = copyTuple;
1916
1917         return EvalPlanQualNext(estate);
1918 }
1919
1920 static TupleTableSlot *
1921 EvalPlanQualNext(EState *estate)
1922 {
1923         evalPlanQual *epq = estate->es_evalPlanQual;
1924         MemoryContext oldcontext;
1925         TupleTableSlot *slot;
1926
1927         Assert(epq->rti != 0);
1928
1929 lpqnext:;
1930         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1931         slot = ExecProcNode(epq->planstate);
1932         MemoryContextSwitchTo(oldcontext);
1933
1934         /*
1935          * No more tuples for this PQ. Continue previous one.
1936          */
1937         if (TupIsNull(slot))
1938         {
1939                 evalPlanQual *oldepq;
1940
1941                 /* stop execution */
1942                 EvalPlanQualStop(epq);
1943                 /* pop old PQ from the stack */
1944                 oldepq = epq->next;
1945                 if (oldepq == NULL)
1946                 {
1947                         /* this is the first (oldest) PQ - mark as free */
1948                         epq->rti = 0;
1949                         estate->es_useEvalPlan = false;
1950                         /* and continue Query execution */
1951                         return (NULL);
1952                 }
1953                 Assert(oldepq->rti != 0);
1954                 /* push current PQ to freePQ stack */
1955                 oldepq->free = epq;
1956                 epq = oldepq;
1957                 estate->es_evalPlanQual = epq;
1958                 goto lpqnext;
1959         }
1960
1961         return (slot);
1962 }
1963
1964 static void
1965 EndEvalPlanQual(EState *estate)
1966 {
1967         evalPlanQual *epq = estate->es_evalPlanQual;
1968
1969         if (epq->rti == 0)                      /* plans already shutdowned */
1970         {
1971                 Assert(epq->next == NULL);
1972                 return;
1973         }
1974
1975         for (;;)
1976         {
1977                 evalPlanQual *oldepq;
1978
1979                 /* stop execution */
1980                 EvalPlanQualStop(epq);
1981                 /* pop old PQ from the stack */
1982                 oldepq = epq->next;
1983                 if (oldepq == NULL)
1984                 {
1985                         /* this is the first (oldest) PQ - mark as free */
1986                         epq->rti = 0;
1987                         estate->es_useEvalPlan = false;
1988                         break;
1989                 }
1990                 Assert(oldepq->rti != 0);
1991                 /* push current PQ to freePQ stack */
1992                 oldepq->free = epq;
1993                 epq = oldepq;
1994                 estate->es_evalPlanQual = epq;
1995         }
1996 }
1997
1998 /*
1999  * Start execution of one level of PlanQual.
2000  *
2001  * This is a cut-down version of ExecutorStart(): we copy some state from
2002  * the top-level estate rather than initializing it fresh.
2003  */
2004 static void
2005 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2006 {
2007         EState     *epqstate;
2008         int                     rtsize;
2009         MemoryContext oldcontext;
2010
2011         rtsize = length(estate->es_range_table);
2012
2013         epq->estate = epqstate = CreateExecutorState();
2014
2015         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2016
2017         /*
2018          * The epqstates share the top query's copy of unchanging state such
2019          * as the snapshot, rangetable, result-rel info, and external Param info.
2020          * They need their own copies of local state, including a tuple table,
2021          * es_param_exec_vals, etc.
2022          */
2023         epqstate->es_direction = ForwardScanDirection;
2024         epqstate->es_snapshot = estate->es_snapshot;
2025         epqstate->es_range_table = estate->es_range_table;
2026         epqstate->es_result_relations = estate->es_result_relations;
2027         epqstate->es_num_result_relations = estate->es_num_result_relations;
2028         epqstate->es_result_relation_info = estate->es_result_relation_info;
2029         epqstate->es_junkFilter = estate->es_junkFilter;
2030         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2031         epqstate->es_param_list_info = estate->es_param_list_info;
2032         if (estate->es_topPlan->nParamExec > 0)
2033                 epqstate->es_param_exec_vals = (ParamExecData *)
2034                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2035         epqstate->es_rowMark = estate->es_rowMark;
2036         epqstate->es_instrument = estate->es_instrument;
2037         epqstate->es_force_oids = estate->es_force_oids;
2038         epqstate->es_topPlan = estate->es_topPlan;
2039         /*
2040          * Each epqstate must have its own es_evTupleNull state, but
2041          * all the stack entries share es_evTuple state.  This allows
2042          * sub-rechecks to inherit the value being examined by an
2043          * outer recheck.
2044          */
2045         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2046         if (priorepq == NULL)
2047                 /* first PQ stack entry */
2048                 epqstate->es_evTuple = (HeapTuple *)
2049                         palloc0(rtsize * sizeof(HeapTuple));
2050         else
2051                 /* later stack entries share the same storage */
2052                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2053
2054         epqstate->es_tupleTable =
2055                 ExecCreateTupleTable(estate->es_tupleTable->size);
2056
2057         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2058
2059         MemoryContextSwitchTo(oldcontext);
2060 }
2061
2062 /*
2063  * End execution of one level of PlanQual.
2064  *
2065  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2066  * of the normal cleanup, but *not* close result relations (which we are
2067  * just sharing from the outer query).
2068  */
2069 static void
2070 EvalPlanQualStop(evalPlanQual *epq)
2071 {
2072         EState     *epqstate = epq->estate;
2073         MemoryContext oldcontext;
2074
2075         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2076
2077         ExecEndNode(epq->planstate);
2078
2079         ExecDropTupleTable(epqstate->es_tupleTable, true);
2080         epqstate->es_tupleTable = NULL;
2081
2082         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2083         {
2084                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2085                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2086         }
2087
2088         MemoryContextSwitchTo(oldcontext);
2089
2090         FreeExecutorState(epqstate);
2091
2092         epq->estate = NULL;
2093         epq->planstate = NULL;
2094 }