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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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  *        $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.214 2003/08/04 02:39:58 momjian Exp $
  30  *
  31  *-------------------------------------------------------------------------
  32  */
  33 #include "postgres.h"
  34
  35 #include "access/heapam.h"
  36 #include "catalog/heap.h"
  37 #include "catalog/namespace.h"
  38 #include "commands/tablecmds.h"
  39 #include "commands/trigger.h"
  40 #include "executor/execdebug.h"
  41 #include "executor/execdefs.h"
  42 #include "miscadmin.h"
  43 #include "optimizer/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 are
 126          * 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
 366          * prepared 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 top
 488          * 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                 /*
 575                  * For now, always create OIDs in SELECT INTO; this is for
 576                  * backwards compatibility with pre-7.3 behavior.  Eventually we
 577                  * might want to allow the user to choose.
 578                  */
 579                 estate->es_force_oids = true;
 580         }
 581
 582         /*
 583          * Have to lock relations selected for update
 584          */
 585         estate->es_rowMark = NIL;
 586         if (parseTree->rowMarks != NIL)
 587         {
 588                 List       *l;
 589
 590                 foreach(l, parseTree->rowMarks)
 591                 {
 592                         Index           rti = lfirsti(l);
 593                         Oid                     relid = getrelid(rti, rangeTable);
 594                         Relation        relation;
 595                         execRowMark *erm;
 596
 597                         relation = heap_open(relid, RowShareLock);
 598                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 599                         erm->relation = relation;
 600                         erm->rti = rti;
 601                         snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
 602                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 603                 }
 604         }
 605
 606         /*
 607          * initialize the executor "tuple" table.  We need slots for all the
 608          * plan nodes, plus possibly output slots for the junkfilter(s). At
 609          * this point we aren't sure if we need junkfilters, so just add slots
 610          * for them unconditionally.
 611          */
 612         {
 613                 int                     nSlots = ExecCountSlotsNode(plan);
 614
 615                 if (parseTree->resultRelations != NIL)
 616                         nSlots += length(parseTree->resultRelations);
 617                 else
 618                         nSlots += 1;
 619                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 620         }
 621
 622         /* mark EvalPlanQual not active */
 623         estate->es_topPlan = plan;
 624         estate->es_evalPlanQual = NULL;
 625         estate->es_evTupleNull = NULL;
 626         estate->es_evTuple = NULL;
 627         estate->es_useEvalPlan = false;
 628
 629         /*
 630          * initialize the private state information for all the nodes in the
 631          * query tree.  This opens files, allocates storage and leaves us
 632          * ready to start processing tuples.
 633          */
 634         planstate = ExecInitNode(plan, estate);
 635
 636         /*
 637          * Get the tuple descriptor describing the type of tuples to return.
 638          * (this is especially important if we are creating a relation with
 639          * "SELECT INTO")
 640          */
 641         tupType = ExecGetResultType(planstate);
 642
 643         /*
 644          * Initialize the junk filter if needed.  SELECT and INSERT queries
 645          * need a filter if there are any junk attrs in the tlist.      INSERT and
 646          * SELECT INTO also need a filter if the top plan node is a scan node
 647          * that's not doing projection (else we'll be scribbling on the scan
 648          * tuple!)      UPDATE and DELETE always need a filter, since there's
 649          * always a junk 'ctid' attribute present --- no need to look first.
 650          */
 651         {
 652                 bool            junk_filter_needed = false;
 653                 List       *tlist;
 654
 655                 switch (operation)
 656                 {
 657                         case CMD_SELECT:
 658                         case CMD_INSERT:
 659                                 foreach(tlist, plan->targetlist)
 660                                 {
 661                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 662
 663                                         if (tle->resdom->resjunk)
 664                                         {
 665                                                 junk_filter_needed = true;
 666                                                 break;
 667                                         }
 668                                 }
 669                                 if (!junk_filter_needed &&
 670                                         (operation == CMD_INSERT || do_select_into))
 671                                 {
 672                                         if (IsA(planstate, SeqScanState) ||
 673                                                 IsA(planstate, IndexScanState) ||
 674                                                 IsA(planstate, TidScanState) ||
 675                                                 IsA(planstate, SubqueryScanState) ||
 676                                                 IsA(planstate, FunctionScanState))
 677                                         {
 678                                                 if (planstate->ps_ProjInfo == NULL)
 679                                                         junk_filter_needed = true;
 680                                         }
 681                                 }
 682                                 break;
 683                         case CMD_UPDATE:
 684                         case CMD_DELETE:
 685                                 junk_filter_needed = true;
 686                                 break;
 687                         default:
 688                                 break;
 689                 }
 690
 691                 if (junk_filter_needed)
 692                 {
 693                         /*
 694                          * If there are multiple result relations, each one needs its
 695                          * own junk filter.  Note this is only possible for
 696                          * UPDATE/DELETE, so we can't be fooled by some needing a
 697                          * filter and some not.
 698                          */
 699                         if (parseTree->resultRelations != NIL)
 700                         {
 701                                 PlanState **appendplans;
 702                                 int                     as_nplans;
 703                                 ResultRelInfo *resultRelInfo;
 704                                 int                     i;
 705
 706                                 /* Top plan had better be an Append here. */
 707                                 Assert(IsA(plan, Append));
 708                                 Assert(((Append *) plan)->isTarget);
 709                                 Assert(IsA(planstate, AppendState));
 710                                 appendplans = ((AppendState *) planstate)->appendplans;
 711                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 712                                 Assert(as_nplans == estate->es_num_result_relations);
 713                                 resultRelInfo = estate->es_result_relations;
 714                                 for (i = 0; i < as_nplans; i++)
 715                                 {
 716                                         PlanState  *subplan = appendplans[i];
 717                                         JunkFilter *j;
 718
 719                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 720                                                                                    ExecGetResultType(subplan),
 721                                                           ExecAllocTableSlot(estate->es_tupleTable));
 722                                         resultRelInfo->ri_junkFilter = j;
 723                                         resultRelInfo++;
 724                                 }
 725
 726                                 /*
 727                                  * Set active junkfilter too; at this point ExecInitAppend
 728                                  * has already selected an active result relation...
 729                                  */
 730                                 estate->es_junkFilter =
 731                                         estate->es_result_relation_info->ri_junkFilter;
 732                         }
 733                         else
 734                         {
 735                                 /* Normal case with just one JunkFilter */
 736                                 JunkFilter *j;
 737
 738                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 739                                                                            tupType,
 740                                                           ExecAllocTableSlot(estate->es_tupleTable));
 741                                 estate->es_junkFilter = j;
 742                                 if (estate->es_result_relation_info)
 743                                         estate->es_result_relation_info->ri_junkFilter = j;
 744
 745                                 /* For SELECT, want to return the cleaned tuple type */
 746                                 if (operation == CMD_SELECT)
 747                                         tupType = j->jf_cleanTupType;
 748                         }
 749                 }
 750                 else
 751                         estate->es_junkFilter = NULL;
 752         }
 753
 754         /*
 755          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 756          * till now so we have the "clean" result tuple type to create the new
 757          * table from.
 758          *
 759          * If EXPLAIN, skip creating the "into" relation.
 760          */
 761         intoRelationDesc = (Relation) NULL;
 762
 763         if (do_select_into && !explainOnly)
 764         {
 765                 char       *intoName;
 766                 Oid                     namespaceId;
 767                 AclResult       aclresult;
 768                 Oid                     intoRelationId;
 769                 TupleDesc       tupdesc;
 770
 771                 /*
 772                  * find namespace to create in, check permissions
 773                  */
 774                 intoName = parseTree->into->relname;
 775                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 776
 777                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 778                                                                                   ACL_CREATE);
 779                 if (aclresult != ACLCHECK_OK)
 780                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 781                                                    get_namespace_name(namespaceId));
 782
 783                 /*
 784                  * have to copy tupType to get rid of constraints
 785                  */
 786                 tupdesc = CreateTupleDescCopy(tupType);
 787
 788                 intoRelationId = heap_create_with_catalog(intoName,
 789                                                                                                   namespaceId,
 790                                                                                                   tupdesc,
 791                                                                                                   RELKIND_RELATION,
 792                                                                                                   false,
 793                                                                                                   ONCOMMIT_NOOP,
 794                                                                                                   allowSystemTableMods);
 795
 796                 FreeTupleDesc(tupdesc);
 797
 798                 /*
 799                  * Advance command counter so that the newly-created relation's
 800                  * catalog tuples will be visible to heap_open.
 801                  */
 802                 CommandCounterIncrement();
 803
 804                 /*
 805                  * If necessary, create a TOAST table for the into relation. Note
 806                  * that AlterTableCreateToastTable ends with
 807                  * CommandCounterIncrement(), so that the TOAST table will be
 808                  * visible for insertion.
 809                  */
 810                 AlterTableCreateToastTable(intoRelationId, true);
 811
 812                 /*
 813                  * And open the constructed table for writing.
 814                  */
 815                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 816         }
 817
 818         estate->es_into_relation_descriptor = intoRelationDesc;
 819
 820         queryDesc->tupDesc = tupType;
 821         queryDesc->planstate = planstate;
 822 }
 823
 824 /*
 825  * Initialize ResultRelInfo data for one result relation
 826  */
 827 static void
 828 initResultRelInfo(ResultRelInfo *resultRelInfo,
 829                                   Index resultRelationIndex,
 830                                   List *rangeTable,
 831                                   CmdType operation)
 832 {
 833         Oid                     resultRelationOid;
 834         Relation        resultRelationDesc;
 835
 836         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 837         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 838
 839         switch (resultRelationDesc->rd_rel->relkind)
 840         {
 841                 case RELKIND_SEQUENCE:
 842                         ereport(ERROR,
 843                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 844                                          errmsg("cannot change sequence relation \"%s\"",
 845                                                   RelationGetRelationName(resultRelationDesc))));
 846                         break;
 847                 case RELKIND_TOASTVALUE:
 848                         ereport(ERROR,
 849                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 850                                          errmsg("cannot change toast relation \"%s\"",
 851                                                   RelationGetRelationName(resultRelationDesc))));
 852                         break;
 853                 case RELKIND_VIEW:
 854                         ereport(ERROR,
 855                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 856                                          errmsg("cannot change view relation \"%s\"",
 857                                                   RelationGetRelationName(resultRelationDesc))));
 858                         break;
 859         }
 860
 861         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 862         resultRelInfo->type = T_ResultRelInfo;
 863         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 864         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 865         resultRelInfo->ri_NumIndices = 0;
 866         resultRelInfo->ri_IndexRelationDescs = NULL;
 867         resultRelInfo->ri_IndexRelationInfo = NULL;
 868         /* make a copy so as not to depend on relcache info not changing... */
 869         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 870         resultRelInfo->ri_TrigFunctions = NULL;
 871         resultRelInfo->ri_ConstraintExprs = NULL;
 872         resultRelInfo->ri_junkFilter = NULL;
 873
 874         /*
 875          * If there are indices on the result relation, open them and save
 876          * descriptors in the result relation info, so that we can add new
 877          * index entries for the tuples we add/update.  We need not do this
 878          * for a DELETE, however, since deletion doesn't affect indexes.
 879          */
 880         if (resultRelationDesc->rd_rel->relhasindex &&
 881                 operation != CMD_DELETE)
 882                 ExecOpenIndices(resultRelInfo);
 883 }
 884
 885 /* ----------------------------------------------------------------
 886  *              ExecEndPlan
 887  *
 888  *              Cleans up the query plan -- closes files and frees up storage
 889  *
 890  * NOTE: we are no longer very worried about freeing storage per se
 891  * in this code; FreeExecutorState should be guaranteed to release all
 892  * memory that needs to be released.  What we are worried about doing
 893  * is closing relations and dropping buffer pins.  Thus, for example,
 894  * tuple tables must be cleared or dropped to ensure pins are released.
 895  * ----------------------------------------------------------------
 896  */
 897 void
 898 ExecEndPlan(PlanState * planstate, EState *estate)
 899 {
 900         ResultRelInfo *resultRelInfo;
 901         int                     i;
 902         List       *l;
 903
 904         /*
 905          * shut down any PlanQual processing we were doing
 906          */
 907         if (estate->es_evalPlanQual != NULL)
 908                 EndEvalPlanQual(estate);
 909
 910         /*
 911          * shut down the node-type-specific query processing
 912          */
 913         ExecEndNode(planstate);
 914
 915         /*
 916          * destroy the executor "tuple" table.
 917          */
 918         ExecDropTupleTable(estate->es_tupleTable, true);
 919         estate->es_tupleTable = NULL;
 920
 921         /*
 922          * close the result relation(s) if any, but hold locks until xact
 923          * commit.
 924          */
 925         resultRelInfo = estate->es_result_relations;
 926         for (i = estate->es_num_result_relations; i > 0; i--)
 927         {
 928                 /* Close indices and then the relation itself */
 929                 ExecCloseIndices(resultRelInfo);
 930                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 931                 resultRelInfo++;
 932         }
 933
 934         /*
 935          * close the "into" relation if necessary, again keeping lock
 936          */
 937         if (estate->es_into_relation_descriptor != NULL)
 938                 heap_close(estate->es_into_relation_descriptor, NoLock);
 939
 940         /*
 941          * close any relations selected FOR UPDATE, again keeping locks
 942          */
 943         foreach(l, estate->es_rowMark)
 944         {
 945                 execRowMark *erm = lfirst(l);
 946
 947                 heap_close(erm->relation, NoLock);
 948         }
 949 }
 950
 951 /* ----------------------------------------------------------------
 952  *              ExecutePlan
 953  *
 954  *              processes the query plan to retrieve 'numberTuples' tuples in the
 955  *              direction specified.
 956  *
 957  *              Retrieves all tuples if numberTuples is 0
 958  *
 959  *              result is either a slot containing the last tuple in the case
 960  *              of a SELECT or NULL otherwise.
 961  *
 962  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 963  * user can see it
 964  * ----------------------------------------------------------------
 965  */
 966 static TupleTableSlot *
 967 ExecutePlan(EState *estate,
 968                         PlanState * planstate,
 969                         CmdType operation,
 970                         long numberTuples,
 971                         ScanDirection direction,
 972                         DestReceiver *dest)
 973 {
 974         JunkFilter *junkfilter;
 975         TupleTableSlot *slot;
 976         ItemPointer tupleid = NULL;
 977         ItemPointerData tuple_ctid;
 978         long            current_tuple_count;
 979         TupleTableSlot *result;
 980
 981         /*
 982          * initialize local variables
 983          */
 984         slot = NULL;
 985         current_tuple_count = 0;
 986         result = NULL;
 987
 988         /*
 989          * Set the direction.
 990          */
 991         estate->es_direction = direction;
 992
 993         /*
 994          * Process BEFORE EACH STATEMENT triggers
 995          */
 996         switch (operation)
 997         {
 998                 case CMD_UPDATE:
 999                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
1000                         break;
1001                 case CMD_DELETE:
1002                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1003                         break;
1004                 case CMD_INSERT:
1005                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1006                         break;
1007                 default:
1008                         /* do nothing */
1009                         break;
1010         }
1011
1012         /*
1013          * Loop until we've processed the proper number of tuples from the
1014          * plan.
1015          */
1016
1017         for (;;)
1018         {
1019                 /* Reset the per-output-tuple exprcontext */
1020                 ResetPerTupleExprContext(estate);
1021
1022                 /*
1023                  * Execute the plan and obtain a tuple
1024                  */
1025 lnext:  ;
1026                 if (estate->es_useEvalPlan)
1027                 {
1028                         slot = EvalPlanQualNext(estate);
1029                         if (TupIsNull(slot))
1030                                 slot = ExecProcNode(planstate);
1031                 }
1032                 else
1033                         slot = ExecProcNode(planstate);
1034
1035                 /*
1036                  * if the tuple is null, then we assume there is nothing more to
1037                  * process so we just return null...
1038                  */
1039                 if (TupIsNull(slot))
1040                 {
1041                         result = NULL;
1042                         break;
1043                 }
1044
1045                 /*
1046                  * if we have a junk filter, then project a new tuple with the
1047                  * junk removed.
1048                  *
1049                  * Store this new "clean" tuple in the junkfilter's resultSlot.
1050                  * (Formerly, we stored it back over the "dirty" tuple, which is
1051                  * WRONG because that tuple slot has the wrong descriptor.)
1052                  *
1053                  * Also, extract all the junk information we need.
1054                  */
1055                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
1056                 {
1057                         Datum           datum;
1058                         HeapTuple       newTuple;
1059                         bool            isNull;
1060
1061                         /*
1062                          * extract the 'ctid' junk attribute.
1063                          */
1064                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1065                         {
1066                                 if (!ExecGetJunkAttribute(junkfilter,
1067                                                                                   slot,
1068                                                                                   "ctid",
1069                                                                                   &datum,
1070                                                                                   &isNull))
1071                                         elog(ERROR, "could not find junk ctid column");
1072
1073                                 /* shouldn't ever get a null result... */
1074                                 if (isNull)
1075                                         elog(ERROR, "ctid is NULL");
1076
1077                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1078                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1079                                                                                  * ctid!! */
1080                                 tupleid = &tuple_ctid;
1081                         }
1082                         else if (estate->es_rowMark != NIL)
1083                         {
1084                                 List       *l;
1085
1086                 lmark:  ;
1087                                 foreach(l, estate->es_rowMark)
1088                                 {
1089                                         execRowMark *erm = lfirst(l);
1090                                         Buffer          buffer;
1091                                         HeapTupleData tuple;
1092                                         TupleTableSlot *newSlot;
1093                                         int                     test;
1094
1095                                         if (!ExecGetJunkAttribute(junkfilter,
1096                                                                                           slot,
1097                                                                                           erm->resname,
1098                                                                                           &datum,
1099                                                                                           &isNull))
1100                                                 elog(ERROR, "could not find junk \"%s\" column",
1101                                                          erm->resname);
1102
1103                                         /* shouldn't ever get a null result... */
1104                                         if (isNull)
1105                                                 elog(ERROR, "\"%s\" is NULL", erm->resname);
1106
1107                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1108                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1109                                                                                         estate->es_snapshot->curcid);
1110                                         ReleaseBuffer(buffer);
1111                                         switch (test)
1112                                         {
1113                                                 case HeapTupleSelfUpdated:
1114                                                         /* treat it as deleted; do not process */
1115                                                         goto lnext;
1116
1117                                                 case HeapTupleMayBeUpdated:
1118                                                         break;
1119
1120                                                 case HeapTupleUpdated:
1121                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1122                                                                 ereport(ERROR,
1123                                                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1124                                                                                  errmsg("could not serialize access due to concurrent update")));
1125                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1126                                                                   (ItemPointer) DatumGetPointer(datum))))
1127                                                         {
1128                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1129                                                                 if (!(TupIsNull(newSlot)))
1130                                                                 {
1131                                                                         slot = newSlot;
1132                                                                         estate->es_useEvalPlan = true;
1133                                                                         goto lmark;
1134                                                                 }
1135                                                         }
1136
1137                                                         /*
1138                                                          * if tuple was deleted or PlanQual failed for
1139                                                          * updated tuple - we must not return this
1140                                                          * tuple!
1141                                                          */
1142                                                         goto lnext;
1143
1144                                                 default:
1145                                                         elog(ERROR, "unrecognized heap_mark4update status: %u",
1146                                                                  test);
1147                                                         return (NULL);
1148                                         }
1149                                 }
1150                         }
1151
1152                         /*
1153                          * Finally create a new "clean" tuple with all junk attributes
1154                          * removed
1155                          */
1156                         newTuple = ExecRemoveJunk(junkfilter, slot);
1157
1158                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1159                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1160                                                                   InvalidBuffer,                /* this tuple has no
1161                                                                                                                  * buffer */
1162                                                                   true);                /* tuple should be pfreed */
1163                 }
1164
1165                 /*
1166                  * now that we have a tuple, do the appropriate thing with it..
1167                  * either return it to the user, add it to a relation someplace,
1168                  * delete it from a relation, or modify some of its attributes.
1169                  */
1170                 switch (operation)
1171                 {
1172                         case CMD_SELECT:
1173                                 ExecSelect(slot,        /* slot containing tuple */
1174                                                    dest,        /* destination's tuple-receiver obj */
1175                                                    estate);
1176                                 result = slot;
1177                                 break;
1178
1179                         case CMD_INSERT:
1180                                 ExecInsert(slot, tupleid, estate);
1181                                 result = NULL;
1182                                 break;
1183
1184                         case CMD_DELETE:
1185                                 ExecDelete(slot, tupleid, estate);
1186                                 result = NULL;
1187                                 break;
1188
1189                         case CMD_UPDATE:
1190                                 ExecUpdate(slot, tupleid, estate);
1191                                 result = NULL;
1192                                 break;
1193
1194                         default:
1195                                 elog(ERROR, "unrecognized operation code: %d",
1196                                          (int) operation);
1197                                 result = NULL;
1198                                 break;
1199                 }
1200
1201                 /*
1202                  * check our tuple count.. if we've processed the proper number
1203                  * then quit, else loop again and process more tuples.  Zero
1204                  * numberTuples means no limit.
1205                  */
1206                 current_tuple_count++;
1207                 if (numberTuples && numberTuples == current_tuple_count)
1208                         break;
1209         }
1210
1211         /*
1212          * Process AFTER EACH STATEMENT triggers
1213          */
1214         switch (operation)
1215         {
1216                 case CMD_UPDATE:
1217                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1218                         break;
1219                 case CMD_DELETE:
1220                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1221                         break;
1222                 case CMD_INSERT:
1223                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1224                         break;
1225                 default:
1226                         /* do nothing */
1227                         break;
1228         }
1229
1230         /*
1231          * here, result is either a slot containing a tuple in the case of a
1232          * SELECT or NULL otherwise.
1233          */
1234         return result;
1235 }
1236
1237 /* ----------------------------------------------------------------
1238  *              ExecSelect
1239  *
1240  *              SELECTs are easy.. we just pass the tuple to the appropriate
1241  *              print function.  The only complexity is when we do a
1242  *              "SELECT INTO", in which case we insert the tuple into
1243  *              the appropriate relation (note: this is a newly created relation
1244  *              so we don't need to worry about indices or locks.)
1245  * ----------------------------------------------------------------
1246  */
1247 static void
1248 ExecSelect(TupleTableSlot *slot,
1249                    DestReceiver *dest,
1250                    EState *estate)
1251 {
1252         HeapTuple       tuple;
1253         TupleDesc       attrtype;
1254
1255         /*
1256          * get the heap tuple out of the tuple table slot
1257          */
1258         tuple = slot->val;
1259         attrtype = slot->ttc_tupleDescriptor;
1260
1261         /*
1262          * insert the tuple into the "into relation"
1263          *
1264          * XXX this probably ought to be replaced by a separate destination
1265          */
1266         if (estate->es_into_relation_descriptor != NULL)
1267         {
1268                 heap_insert(estate->es_into_relation_descriptor, tuple,
1269                                         estate->es_snapshot->curcid);
1270                 IncrAppended();
1271         }
1272
1273         /*
1274          * send the tuple to the destination
1275          */
1276         (*dest->receiveTuple) (tuple, attrtype, dest);
1277         IncrRetrieved();
1278         (estate->es_processed)++;
1279 }
1280
1281 /* ----------------------------------------------------------------
1282  *              ExecInsert
1283  *
1284  *              INSERTs are trickier.. we have to insert the tuple into
1285  *              the base relation and insert appropriate tuples into the
1286  *              index relations.
1287  * ----------------------------------------------------------------
1288  */
1289 static void
1290 ExecInsert(TupleTableSlot *slot,
1291                    ItemPointer tupleid,
1292                    EState *estate)
1293 {
1294         HeapTuple       tuple;
1295         ResultRelInfo *resultRelInfo;
1296         Relation        resultRelationDesc;
1297         int                     numIndices;
1298         Oid                     newId;
1299
1300         /*
1301          * get the heap tuple out of the tuple table slot
1302          */
1303         tuple = slot->val;
1304
1305         /*
1306          * get information on the (current) result relation
1307          */
1308         resultRelInfo = estate->es_result_relation_info;
1309         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1310
1311         /* BEFORE ROW INSERT Triggers */
1312         if (resultRelInfo->ri_TrigDesc &&
1313           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1314         {
1315                 HeapTuple       newtuple;
1316
1317                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1318
1319                 if (newtuple == NULL)   /* "do nothing" */
1320                         return;
1321
1322                 if (newtuple != tuple)  /* modified by Trigger(s) */
1323                 {
1324                         /*
1325                          * Insert modified tuple into tuple table slot, replacing the
1326                          * original.  We assume that it was allocated in per-tuple
1327                          * memory context, and therefore will go away by itself. The
1328                          * tuple table slot should not try to clear it.
1329                          */
1330                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1331                         tuple = newtuple;
1332                 }
1333         }
1334
1335         /*
1336          * Check the constraints of the tuple
1337          */
1338         if (resultRelationDesc->rd_att->constr)
1339                 ExecConstraints(resultRelInfo, slot, estate);
1340
1341         /*
1342          * insert the tuple
1343          */
1344         newId = heap_insert(resultRelationDesc, tuple,
1345                                                 estate->es_snapshot->curcid);
1346
1347         IncrAppended();
1348         (estate->es_processed)++;
1349         estate->es_lastoid = newId;
1350         setLastTid(&(tuple->t_self));
1351
1352         /*
1353          * process indices
1354          *
1355          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1356          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1357          * field.
1358          */
1359         numIndices = resultRelInfo->ri_NumIndices;
1360         if (numIndices > 0)
1361                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1362
1363         /* AFTER ROW INSERT Triggers */
1364         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1365 }
1366
1367 /* ----------------------------------------------------------------
1368  *              ExecDelete
1369  *
1370  *              DELETE is like UPDATE, we delete the tuple and its
1371  *              index tuples.
1372  * ----------------------------------------------------------------
1373  */
1374 static void
1375 ExecDelete(TupleTableSlot *slot,
1376                    ItemPointer tupleid,
1377                    EState *estate)
1378 {
1379         ResultRelInfo *resultRelInfo;
1380         Relation        resultRelationDesc;
1381         ItemPointerData ctid;
1382         int                     result;
1383
1384         /*
1385          * get information on the (current) result relation
1386          */
1387         resultRelInfo = estate->es_result_relation_info;
1388         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1389
1390         /* BEFORE ROW DELETE Triggers */
1391         if (resultRelInfo->ri_TrigDesc &&
1392           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1393         {
1394                 bool            dodelete;
1395
1396                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1397                                                                                 estate->es_snapshot->curcid);
1398
1399                 if (!dodelete)                  /* "do nothing" */
1400                         return;
1401         }
1402
1403         /*
1404          * delete the tuple
1405          */
1406 ldelete:;
1407         result = heap_delete(resultRelationDesc, tupleid,
1408                                                  &ctid,
1409                                                  estate->es_snapshot->curcid);
1410         switch (result)
1411         {
1412                 case HeapTupleSelfUpdated:
1413                         /* already deleted by self; nothing to do */
1414                         return;
1415
1416                 case HeapTupleMayBeUpdated:
1417                         break;
1418
1419                 case HeapTupleUpdated:
1420                         if (XactIsoLevel == XACT_SERIALIZABLE)
1421                                 ereport(ERROR,
1422                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1423                                                  errmsg("could not serialize access due to concurrent update")));
1424                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1425                         {
1426                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1427                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1428
1429                                 if (!TupIsNull(epqslot))
1430                                 {
1431                                         *tupleid = ctid;
1432                                         goto ldelete;
1433                                 }
1434                         }
1435                         /* tuple already deleted; nothing to do */
1436                         return;
1437
1438                 default:
1439                         elog(ERROR, "unrecognized heap_delete status: %u", result);
1440                         return;
1441         }
1442
1443         IncrDeleted();
1444         (estate->es_processed)++;
1445
1446         /*
1447          * Note: Normally one would think that we have to delete index tuples
1448          * associated with the heap tuple now..
1449          *
1450          * ... but in POSTGRES, we have no need to do this because the vacuum
1451          * daemon automatically opens an index scan and deletes index tuples
1452          * when it finds deleted heap tuples. -cim 9/27/89
1453          */
1454
1455         /* AFTER ROW DELETE Triggers */
1456         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1457 }
1458
1459 /* ----------------------------------------------------------------
1460  *              ExecUpdate
1461  *
1462  *              note: we can't run UPDATE queries with transactions
1463  *              off because UPDATEs are actually INSERTs and our
1464  *              scan will mistakenly loop forever, updating the tuple
1465  *              it just inserted..      This should be fixed but until it
1466  *              is, we don't want to get stuck in an infinite loop
1467  *              which corrupts your database..
1468  * ----------------------------------------------------------------
1469  */
1470 static void
1471 ExecUpdate(TupleTableSlot *slot,
1472                    ItemPointer tupleid,
1473                    EState *estate)
1474 {
1475         HeapTuple       tuple;
1476         ResultRelInfo *resultRelInfo;
1477         Relation        resultRelationDesc;
1478         ItemPointerData ctid;
1479         int                     result;
1480         int                     numIndices;
1481
1482         /*
1483          * abort the operation if not running transactions
1484          */
1485         if (IsBootstrapProcessingMode())
1486                 elog(ERROR, "cannot UPDATE during bootstrap");
1487
1488         /*
1489          * get the heap tuple out of the tuple table slot
1490          */
1491         tuple = slot->val;
1492
1493         /*
1494          * get information on the (current) result relation
1495          */
1496         resultRelInfo = estate->es_result_relation_info;
1497         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1498
1499         /* BEFORE ROW UPDATE Triggers */
1500         if (resultRelInfo->ri_TrigDesc &&
1501           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1502         {
1503                 HeapTuple       newtuple;
1504
1505                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1506                                                                                 tupleid, tuple,
1507                                                                                 estate->es_snapshot->curcid);
1508
1509                 if (newtuple == NULL)   /* "do nothing" */
1510                         return;
1511
1512                 if (newtuple != tuple)  /* modified by Trigger(s) */
1513                 {
1514                         /*
1515                          * Insert modified tuple into tuple table slot, replacing the
1516                          * original.  We assume that it was allocated in per-tuple
1517                          * memory context, and therefore will go away by itself. The
1518                          * tuple table slot should not try to clear it.
1519                          */
1520                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1521                         tuple = newtuple;
1522                 }
1523         }
1524
1525         /*
1526          * Check the constraints of the tuple
1527          *
1528          * If we generate a new candidate tuple after EvalPlanQual testing, we
1529          * must loop back here and recheck constraints.  (We don't need to
1530          * redo triggers, however.      If there are any BEFORE triggers then
1531          * trigger.c will have done mark4update to lock the correct tuple, so
1532          * there's no need to do them again.)
1533          */
1534 lreplace:;
1535         if (resultRelationDesc->rd_att->constr)
1536                 ExecConstraints(resultRelInfo, slot, estate);
1537
1538         /*
1539          * replace the heap tuple
1540          */
1541         result = heap_update(resultRelationDesc, tupleid, tuple,
1542                                                  &ctid,
1543                                                  estate->es_snapshot->curcid);
1544         switch (result)
1545         {
1546                 case HeapTupleSelfUpdated:
1547                         /* already deleted by self; nothing to do */
1548                         return;
1549
1550                 case HeapTupleMayBeUpdated:
1551                         break;
1552
1553                 case HeapTupleUpdated:
1554                         if (XactIsoLevel == XACT_SERIALIZABLE)
1555                                 ereport(ERROR,
1556                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1557                                                  errmsg("could not serialize access due to concurrent update")));
1558                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1559                         {
1560                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1561                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1562
1563                                 if (!TupIsNull(epqslot))
1564                                 {
1565                                         *tupleid = ctid;
1566                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1567                                         slot = ExecStoreTuple(tuple,
1568                                                                         estate->es_junkFilter->jf_resultSlot,
1569                                                                                   InvalidBuffer, true);
1570                                         goto lreplace;
1571                                 }
1572                         }
1573                         /* tuple already deleted; nothing to do */
1574                         return;
1575
1576                 default:
1577                         elog(ERROR, "unrecognized heap_update status: %u", result);
1578                         return;
1579         }
1580
1581         IncrReplaced();
1582         (estate->es_processed)++;
1583
1584         /*
1585          * Note: instead of having to update the old index tuples associated
1586          * with the heap tuple, all we do is form and insert new index tuples.
1587          * This is because UPDATEs are actually DELETEs and INSERTs and index
1588          * tuple deletion is done automagically by the vacuum daemon. All we
1589          * do is insert new index tuples.  -cim 9/27/89
1590          */
1591
1592         /*
1593          * process indices
1594          *
1595          * heap_update updates a tuple in the base relation by invalidating it
1596          * and then inserting a new tuple to the relation.      As a side effect,
1597          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1598          * field.  So we now insert index tuples using the new tupleid stored
1599          * there.
1600          */
1601
1602         numIndices = resultRelInfo->ri_NumIndices;
1603         if (numIndices > 0)
1604                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1605
1606         /* AFTER ROW UPDATE Triggers */
1607         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1608 }
1609
1610 static const char *
1611 ExecRelCheck(ResultRelInfo *resultRelInfo,
1612                          TupleTableSlot *slot, EState *estate)
1613 {
1614         Relation        rel = resultRelInfo->ri_RelationDesc;
1615         int                     ncheck = rel->rd_att->constr->num_check;
1616         ConstrCheck *check = rel->rd_att->constr->check;
1617         ExprContext *econtext;
1618         MemoryContext oldContext;
1619         List       *qual;
1620         int                     i;
1621
1622         /*
1623          * If first time through for this result relation, build expression
1624          * nodetrees for rel's constraint expressions.  Keep them in the
1625          * per-query memory context so they'll survive throughout the query.
1626          */
1627         if (resultRelInfo->ri_ConstraintExprs == NULL)
1628         {
1629                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1630                 resultRelInfo->ri_ConstraintExprs =
1631                         (List **) palloc(ncheck * sizeof(List *));
1632                 for (i = 0; i < ncheck; i++)
1633                 {
1634                         qual = (List *) stringToNode(check[i].ccbin);
1635                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1636                                 ExecPrepareExpr((Expr *) qual, estate);
1637                 }
1638                 MemoryContextSwitchTo(oldContext);
1639         }
1640
1641         /*
1642          * We will use the EState's per-tuple context for evaluating
1643          * constraint expressions (creating it if it's not already there).
1644          */
1645         econtext = GetPerTupleExprContext(estate);
1646
1647         /* Arrange for econtext's scan tuple to be the tuple under test */
1648         econtext->ecxt_scantuple = slot;
1649
1650         /* And evaluate the constraints */
1651         for (i = 0; i < ncheck; i++)
1652         {
1653                 qual = resultRelInfo->ri_ConstraintExprs[i];
1654
1655                 /*
1656                  * NOTE: SQL92 specifies that a NULL result from a constraint
1657                  * expression is not to be treated as a failure.  Therefore, tell
1658                  * ExecQual to return TRUE for NULL.
1659                  */
1660                 if (!ExecQual(qual, econtext, true))
1661                         return check[i].ccname;
1662         }
1663
1664         /* NULL result means no error */
1665         return NULL;
1666 }
1667
1668 void
1669 ExecConstraints(ResultRelInfo *resultRelInfo,
1670                                 TupleTableSlot *slot, EState *estate)
1671 {
1672         Relation        rel = resultRelInfo->ri_RelationDesc;
1673         HeapTuple       tuple = slot->val;
1674         TupleConstr *constr = rel->rd_att->constr;
1675
1676         Assert(constr);
1677
1678         if (constr->has_not_null)
1679         {
1680                 int                     natts = rel->rd_att->natts;
1681                 int                     attrChk;
1682
1683                 for (attrChk = 1; attrChk <= natts; attrChk++)
1684                 {
1685                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1686                                 heap_attisnull(tuple, attrChk))
1687                                 ereport(ERROR,
1688                                                 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1689                                                  errmsg("null value for attribute \"%s\" violates NOT NULL constraint",
1690                                         NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1691                 }
1692         }
1693
1694         if (constr->num_check > 0)
1695         {
1696                 const char *failed;
1697
1698                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1699                         ereport(ERROR,
1700                                         (errcode(ERRCODE_CHECK_VIOLATION),
1701                                          errmsg("new row for relation \"%s\" violates CHECK constraint \"%s\"",
1702                                                         RelationGetRelationName(rel), failed)));
1703         }
1704 }
1705
1706 /*
1707  * Check a modified tuple to see if we want to process its updated version
1708  * under READ COMMITTED rules.
1709  *
1710  * See backend/executor/README for some info about how this works.
1711  */
1712 TupleTableSlot *
1713 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1714 {
1715         evalPlanQual *epq;
1716         EState     *epqstate;
1717         Relation        relation;
1718         HeapTupleData tuple;
1719         HeapTuple       copyTuple = NULL;
1720         bool            endNode;
1721
1722         Assert(rti != 0);
1723
1724         /*
1725          * find relation containing target tuple
1726          */
1727         if (estate->es_result_relation_info != NULL &&
1728                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1729                 relation = estate->es_result_relation_info->ri_RelationDesc;
1730         else
1731         {
1732                 List       *l;
1733
1734                 relation = NULL;
1735                 foreach(l, estate->es_rowMark)
1736                 {
1737                         if (((execRowMark *) lfirst(l))->rti == rti)
1738                         {
1739                                 relation = ((execRowMark *) lfirst(l))->relation;
1740                                 break;
1741                         }
1742                 }
1743                 if (relation == NULL)
1744                         elog(ERROR, "could not find RowMark for RT index %u", rti);
1745         }
1746
1747         /*
1748          * fetch tid tuple
1749          *
1750          * Loop here to deal with updated or busy tuples
1751          */
1752         tuple.t_self = *tid;
1753         for (;;)
1754         {
1755                 Buffer          buffer;
1756
1757                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1758                 {
1759                         TransactionId xwait = SnapshotDirty->xmax;
1760
1761                         /* xmin should not be dirty... */
1762                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1763                                 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1764
1765                         /*
1766                          * If tuple is being updated by other transaction then we have
1767                          * to wait for its commit/abort.
1768                          */
1769                         if (TransactionIdIsValid(xwait))
1770                         {
1771                                 ReleaseBuffer(buffer);
1772                                 XactLockTableWait(xwait);
1773                                 continue;
1774                         }
1775
1776                         /*
1777                          * We got tuple - now copy it for use by recheck query.
1778                          */
1779                         copyTuple = heap_copytuple(&tuple);
1780                         ReleaseBuffer(buffer);
1781                         break;
1782                 }
1783
1784                 /*
1785                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1786                  * Note that it's possible to get invalid SnapshotDirty->tid if
1787                  * tuple updated by this transaction. Have we to check this ?
1788                  */
1789                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1790                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1791                 {
1792                         /* updated, so look at the updated copy */
1793                         tuple.t_self = SnapshotDirty->tid;
1794                         continue;
1795                 }
1796
1797                 /*
1798                  * Deleted or updated by this transaction; forget it.
1799                  */
1800                 return NULL;
1801         }
1802
1803         /*
1804          * For UPDATE/DELETE we have to return tid of actual row we're
1805          * executing PQ for.
1806          */
1807         *tid = tuple.t_self;
1808
1809         /*
1810          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1811          */
1812         epq = estate->es_evalPlanQual;
1813         endNode = true;
1814
1815         if (epq != NULL && epq->rti == 0)
1816         {
1817                 /* Top PQ stack entry is idle, so re-use it */
1818                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1819                 epq->rti = rti;
1820                 endNode = false;
1821         }
1822
1823         /*
1824          * If this is request for another RTE - Ra, - then we have to check
1825          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1826          * updated again and we have to re-start old execution for Ra and
1827          * forget all what we done after Ra was suspended. Cool? -:))
1828          */
1829         if (epq != NULL && epq->rti != rti &&
1830                 epq->estate->es_evTuple[rti - 1] != NULL)
1831         {
1832                 do
1833                 {
1834                         evalPlanQual *oldepq;
1835
1836                         /* stop execution */
1837                         EvalPlanQualStop(epq);
1838                         /* pop previous PlanQual from the stack */
1839                         oldepq = epq->next;
1840                         Assert(oldepq && oldepq->rti != 0);
1841                         /* push current PQ to freePQ stack */
1842                         oldepq->free = epq;
1843                         epq = oldepq;
1844                         estate->es_evalPlanQual = epq;
1845                 } while (epq->rti != rti);
1846         }
1847
1848         /*
1849          * If we are requested for another RTE then we have to suspend
1850          * execution of current PlanQual and start execution for new one.
1851          */
1852         if (epq == NULL || epq->rti != rti)
1853         {
1854                 /* try to reuse plan used previously */
1855                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1856
1857                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1858                 {
1859                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1860                         newepq->free = NULL;
1861                         newepq->estate = NULL;
1862                         newepq->planstate = NULL;
1863                 }
1864                 else
1865                 {
1866                         /* recycle previously used PlanQual */
1867                         Assert(newepq->estate == NULL);
1868                         epq->free = NULL;
1869                 }
1870                 /* push current PQ to the stack */
1871                 newepq->next = epq;
1872                 epq = newepq;
1873                 estate->es_evalPlanQual = epq;
1874                 epq->rti = rti;
1875                 endNode = false;
1876         }
1877
1878         Assert(epq->rti == rti);
1879
1880         /*
1881          * Ok - we're requested for the same RTE.  Unfortunately we still have
1882          * to end and restart execution of the plan, because ExecReScan
1883          * wouldn't ensure that upper plan nodes would reset themselves.  We
1884          * could make that work if insertion of the target tuple were
1885          * integrated with the Param mechanism somehow, so that the upper plan
1886          * nodes know that their children's outputs have changed.
1887          *
1888          * Note that the stack of free evalPlanQual nodes is quite useless at the
1889          * moment, since it only saves us from pallocing/releasing the
1890          * evalPlanQual nodes themselves.  But it will be useful once we
1891          * implement ReScan instead of end/restart for re-using PlanQual
1892          * nodes.
1893          */
1894         if (endNode)
1895         {
1896                 /* stop execution */
1897                 EvalPlanQualStop(epq);
1898         }
1899
1900         /*
1901          * Initialize new recheck query.
1902          *
1903          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to
1904          * instead copy down changeable state from the top plan (including
1905          * es_result_relation_info, es_junkFilter) and reset locally
1906          * changeable state in the epq (including es_param_exec_vals,
1907          * es_evTupleNull).
1908          */
1909         EvalPlanQualStart(epq, estate, epq->next);
1910
1911         /*
1912          * free old RTE' tuple, if any, and store target tuple where
1913          * relation's scan node will see it
1914          */
1915         epqstate = epq->estate;
1916         if (epqstate->es_evTuple[rti - 1] != NULL)
1917                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1918         epqstate->es_evTuple[rti - 1] = copyTuple;
1919
1920         return EvalPlanQualNext(estate);
1921 }
1922
1923 static TupleTableSlot *
1924 EvalPlanQualNext(EState *estate)
1925 {
1926         evalPlanQual *epq = estate->es_evalPlanQual;
1927         MemoryContext oldcontext;
1928         TupleTableSlot *slot;
1929
1930         Assert(epq->rti != 0);
1931
1932 lpqnext:;
1933         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1934         slot = ExecProcNode(epq->planstate);
1935         MemoryContextSwitchTo(oldcontext);
1936
1937         /*
1938          * No more tuples for this PQ. Continue previous one.
1939          */
1940         if (TupIsNull(slot))
1941         {
1942                 evalPlanQual *oldepq;
1943
1944                 /* stop execution */
1945                 EvalPlanQualStop(epq);
1946                 /* pop old PQ from the stack */
1947                 oldepq = epq->next;
1948                 if (oldepq == NULL)
1949                 {
1950                         /* this is the first (oldest) PQ - mark as free */
1951                         epq->rti = 0;
1952                         estate->es_useEvalPlan = false;
1953                         /* and continue Query execution */
1954                         return (NULL);
1955                 }
1956                 Assert(oldepq->rti != 0);
1957                 /* push current PQ to freePQ stack */
1958                 oldepq->free = epq;
1959                 epq = oldepq;
1960                 estate->es_evalPlanQual = epq;
1961                 goto lpqnext;
1962         }
1963
1964         return (slot);
1965 }
1966
1967 static void
1968 EndEvalPlanQual(EState *estate)
1969 {
1970         evalPlanQual *epq = estate->es_evalPlanQual;
1971
1972         if (epq->rti == 0)                      /* plans already shutdowned */
1973         {
1974                 Assert(epq->next == NULL);
1975                 return;
1976         }
1977
1978         for (;;)
1979         {
1980                 evalPlanQual *oldepq;
1981
1982                 /* stop execution */
1983                 EvalPlanQualStop(epq);
1984                 /* pop old PQ from the stack */
1985                 oldepq = epq->next;
1986                 if (oldepq == NULL)
1987                 {
1988                         /* this is the first (oldest) PQ - mark as free */
1989                         epq->rti = 0;
1990                         estate->es_useEvalPlan = false;
1991                         break;
1992                 }
1993                 Assert(oldepq->rti != 0);
1994                 /* push current PQ to freePQ stack */
1995                 oldepq->free = epq;
1996                 epq = oldepq;
1997                 estate->es_evalPlanQual = epq;
1998         }
1999 }
2000
2001 /*
2002  * Start execution of one level of PlanQual.
2003  *
2004  * This is a cut-down version of ExecutorStart(): we copy some state from
2005  * the top-level estate rather than initializing it fresh.
2006  */
2007 static void
2008 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2009 {
2010         EState     *epqstate;
2011         int                     rtsize;
2012         MemoryContext oldcontext;
2013
2014         rtsize = length(estate->es_range_table);
2015
2016         epq->estate = epqstate = CreateExecutorState();
2017
2018         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2019
2020         /*
2021          * The epqstates share the top query's copy of unchanging state such
2022          * as the snapshot, rangetable, result-rel info, and external Param
2023          * info. They need their own copies of local state, including a tuple
2024          * table, es_param_exec_vals, etc.
2025          */
2026         epqstate->es_direction = ForwardScanDirection;
2027         epqstate->es_snapshot = estate->es_snapshot;
2028         epqstate->es_range_table = estate->es_range_table;
2029         epqstate->es_result_relations = estate->es_result_relations;
2030         epqstate->es_num_result_relations = estate->es_num_result_relations;
2031         epqstate->es_result_relation_info = estate->es_result_relation_info;
2032         epqstate->es_junkFilter = estate->es_junkFilter;
2033         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2034         epqstate->es_param_list_info = estate->es_param_list_info;
2035         if (estate->es_topPlan->nParamExec > 0)
2036                 epqstate->es_param_exec_vals = (ParamExecData *)
2037                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2038         epqstate->es_rowMark = estate->es_rowMark;
2039         epqstate->es_instrument = estate->es_instrument;
2040         epqstate->es_force_oids = estate->es_force_oids;
2041         epqstate->es_topPlan = estate->es_topPlan;
2042
2043         /*
2044          * Each epqstate must have its own es_evTupleNull state, but all the
2045          * stack entries share es_evTuple state.  This allows sub-rechecks to
2046          * inherit the value being examined by an outer recheck.
2047          */
2048         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2049         if (priorepq == NULL)
2050                 /* first PQ stack entry */
2051                 epqstate->es_evTuple = (HeapTuple *)
2052                         palloc0(rtsize * sizeof(HeapTuple));
2053         else
2054                 /* later stack entries share the same storage */
2055                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2056
2057         epqstate->es_tupleTable =
2058                 ExecCreateTupleTable(estate->es_tupleTable->size);
2059
2060         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2061
2062         MemoryContextSwitchTo(oldcontext);
2063 }
2064
2065 /*
2066  * End execution of one level of PlanQual.
2067  *
2068  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2069  * of the normal cleanup, but *not* close result relations (which we are
2070  * just sharing from the outer query).
2071  */
2072 static void
2073 EvalPlanQualStop(evalPlanQual *epq)
2074 {
2075         EState     *epqstate = epq->estate;
2076         MemoryContext oldcontext;
2077
2078         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2079
2080         ExecEndNode(epq->planstate);
2081
2082         ExecDropTupleTable(epqstate->es_tupleTable, true);
2083         epqstate->es_tupleTable = NULL;
2084
2085         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2086         {
2087                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2088                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2089         }
2090
2091         MemoryContextSwitchTo(oldcontext);
2092
2093         FreeExecutorState(epqstate);
2094
2095         epq->estate = NULL;
2096         epq->planstate = NULL;
2097 }