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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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) 1996-2005, PostgreSQL Global Development Group
  25  * Portions Copyright (c) 1994, Regents of the University of California
  26  *
  27  *
  28  * IDENTIFICATION
  29  *        $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.249 2005/05/22 22:30:19 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 "executor/instrument.h"
  43 #include "miscadmin.h"
  44 #include "optimizer/clauses.h"
  45 #include "optimizer/var.h"
  46 #include "parser/parsetree.h"
  47 #include "utils/acl.h"
  48 #include "utils/guc.h"
  49 #include "utils/lsyscache.h"
  50 #include "utils/memutils.h"
  51
  52
  53 typedef struct execRowMark
  54 {
  55         Relation        relation;
  56         Index           rti;
  57         char            resname[32];
  58 } execRowMark;
  59
  60 typedef struct evalPlanQual
  61 {
  62         Index           rti;
  63         EState     *estate;
  64         PlanState  *planstate;
  65         struct evalPlanQual *next;      /* stack of active PlanQual plans */
  66         struct evalPlanQual *free;      /* list of free PlanQual plans */
  67 } evalPlanQual;
  68
  69 /* decls for local routines only used within this module */
  70 static void InitPlan(QueryDesc *queryDesc, bool explainOnly);
  71 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  72                                   Index resultRelationIndex,
  73                                   List *rangeTable,
  74                                   CmdType operation,
  75                                   bool doInstrument);
  76 static TupleTableSlot *ExecutePlan(EState *estate, PlanState *planstate,
  77                         CmdType operation,
  78                         long numberTuples,
  79                         ScanDirection direction,
  80                         DestReceiver *dest);
  81 static void ExecSelect(TupleTableSlot *slot,
  82                    DestReceiver *dest,
  83                    EState *estate);
  84 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
  85                    EState *estate);
  86 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  87                    EState *estate);
  88 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
  89                    EState *estate);
  90 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  91 static void EndEvalPlanQual(EState *estate);
  92 static void ExecCheckRTEPerms(RangeTblEntry *rte);
  93 static void ExecCheckXactReadOnly(Query *parsetree);
  94 static void EvalPlanQualStart(evalPlanQual *epq, EState *estate,
  95                                   evalPlanQual *priorepq);
  96 static void EvalPlanQualStop(evalPlanQual *epq);
  97
  98 /* end of local decls */
  99
 100
 101 /* ----------------------------------------------------------------
 102  *              ExecutorStart
 103  *
 104  *              This routine must be called at the beginning of any execution of any
 105  *              query plan
 106  *
 107  * Takes a QueryDesc previously created by CreateQueryDesc (it's not real
 108  * clear why we bother to separate the two functions, but...).  The tupDesc
 109  * field of the QueryDesc is filled in to describe the tuples that will be
 110  * returned, and the internal fields (estate and planstate) are set up.
 111  *
 112  * If explainOnly is true, we are not actually intending to run the plan,
 113  * only to set up for EXPLAIN; so skip unwanted side-effects.
 114  *
 115  * NB: the CurrentMemoryContext when this is called will become the parent
 116  * of the per-query context used for this Executor invocation.
 117  * ----------------------------------------------------------------
 118  */
 119 void
 120 ExecutorStart(QueryDesc *queryDesc, bool explainOnly)
 121 {
 122         EState     *estate;
 123         MemoryContext oldcontext;
 124
 125         /* sanity checks: queryDesc must not be started already */
 126         Assert(queryDesc != NULL);
 127         Assert(queryDesc->estate == NULL);
 128
 129         /*
 130          * If the transaction is read-only, we need to check if any writes are
 131          * planned to non-temporary tables.
 132          */
 133         if (XactReadOnly && !explainOnly)
 134                 ExecCheckXactReadOnly(queryDesc->parsetree);
 135
 136         /*
 137          * Build EState, switch into per-query memory context for startup.
 138          */
 139         estate = CreateExecutorState();
 140         queryDesc->estate = estate;
 141
 142         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 143
 144         /*
 145          * Fill in parameters, if any, from queryDesc
 146          */
 147         estate->es_param_list_info = queryDesc->params;
 148
 149         if (queryDesc->plantree->nParamExec > 0)
 150                 estate->es_param_exec_vals = (ParamExecData *)
 151                         palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 152
 153         /*
 154          * Copy other important information into the EState
 155          */
 156         estate->es_snapshot = queryDesc->snapshot;
 157         estate->es_crosscheck_snapshot = queryDesc->crosscheck_snapshot;
 158         estate->es_instrument = queryDesc->doInstrument;
 159
 160         /*
 161          * Initialize the plan state tree
 162          */
 163         InitPlan(queryDesc, explainOnly);
 164
 165         MemoryContextSwitchTo(oldcontext);
 166 }
 167
 168 /* ----------------------------------------------------------------
 169  *              ExecutorRun
 170  *
 171  *              This is the main routine of the executor module. It accepts
 172  *              the query descriptor from the traffic cop and executes the
 173  *              query plan.
 174  *
 175  *              ExecutorStart must have been called already.
 176  *
 177  *              If direction is NoMovementScanDirection then nothing is done
 178  *              except to start up/shut down the destination.  Otherwise,
 179  *              we retrieve up to 'count' tuples in the specified direction.
 180  *
 181  *              Note: count = 0 is interpreted as no portal limit, i.e., run to
 182  *              completion.
 183  *
 184  * ----------------------------------------------------------------
 185  */
 186 TupleTableSlot *
 187 ExecutorRun(QueryDesc *queryDesc,
 188                         ScanDirection direction, long count)
 189 {
 190         EState     *estate;
 191         CmdType         operation;
 192         DestReceiver *dest;
 193         TupleTableSlot *result;
 194         MemoryContext oldcontext;
 195
 196         /* sanity checks */
 197         Assert(queryDesc != NULL);
 198
 199         estate = queryDesc->estate;
 200
 201         Assert(estate != NULL);
 202
 203         /*
 204          * Switch into per-query memory context
 205          */
 206         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 207
 208         /*
 209          * extract information from the query descriptor and the query
 210          * feature.
 211          */
 212         operation = queryDesc->operation;
 213         dest = queryDesc->dest;
 214
 215         /*
 216          * startup tuple receiver
 217          */
 218         estate->es_processed = 0;
 219         estate->es_lastoid = InvalidOid;
 220
 221         (*dest->rStartup) (dest, operation, queryDesc->tupDesc);
 222
 223         /*
 224          * run plan
 225          */
 226         if (direction == NoMovementScanDirection)
 227                 result = NULL;
 228         else
 229                 result = ExecutePlan(estate,
 230                                                          queryDesc->planstate,
 231                                                          operation,
 232                                                          count,
 233                                                          direction,
 234                                                          dest);
 235
 236         /*
 237          * shutdown receiver
 238          */
 239         (*dest->rShutdown) (dest);
 240
 241         MemoryContextSwitchTo(oldcontext);
 242
 243         return result;
 244 }
 245
 246 /* ----------------------------------------------------------------
 247  *              ExecutorEnd
 248  *
 249  *              This routine must be called at the end of execution of any
 250  *              query plan
 251  * ----------------------------------------------------------------
 252  */
 253 void
 254 ExecutorEnd(QueryDesc *queryDesc)
 255 {
 256         EState     *estate;
 257         MemoryContext oldcontext;
 258
 259         /* sanity checks */
 260         Assert(queryDesc != NULL);
 261
 262         estate = queryDesc->estate;
 263
 264         Assert(estate != NULL);
 265
 266         /*
 267          * Switch into per-query memory context to run ExecEndPlan
 268          */
 269         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 270
 271         ExecEndPlan(queryDesc->planstate, estate);
 272
 273         /*
 274          * Must switch out of context before destroying it
 275          */
 276         MemoryContextSwitchTo(oldcontext);
 277
 278         /*
 279          * Release EState and per-query memory context.  This should release
 280          * everything the executor has allocated.
 281          */
 282         FreeExecutorState(estate);
 283
 284         /* Reset queryDesc fields that no longer point to anything */
 285         queryDesc->tupDesc = NULL;
 286         queryDesc->estate = NULL;
 287         queryDesc->planstate = NULL;
 288 }
 289
 290 /* ----------------------------------------------------------------
 291  *              ExecutorRewind
 292  *
 293  *              This routine may be called on an open queryDesc to rewind it
 294  *              to the start.
 295  * ----------------------------------------------------------------
 296  */
 297 void
 298 ExecutorRewind(QueryDesc *queryDesc)
 299 {
 300         EState     *estate;
 301         MemoryContext oldcontext;
 302
 303         /* sanity checks */
 304         Assert(queryDesc != NULL);
 305
 306         estate = queryDesc->estate;
 307
 308         Assert(estate != NULL);
 309
 310         /* It's probably not sensible to rescan updating queries */
 311         Assert(queryDesc->operation == CMD_SELECT);
 312
 313         /*
 314          * Switch into per-query memory context
 315          */
 316         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 317
 318         /*
 319          * rescan plan
 320          */
 321         ExecReScan(queryDesc->planstate, NULL);
 322
 323         MemoryContextSwitchTo(oldcontext);
 324 }
 325
 326
 327 /*
 328  * ExecCheckRTPerms
 329  *              Check access permissions for all relations listed in a range table.
 330  */
 331 void
 332 ExecCheckRTPerms(List *rangeTable)
 333 {
 334         ListCell   *l;
 335
 336         foreach(l, rangeTable)
 337         {
 338                 RangeTblEntry *rte = lfirst(l);
 339
 340                 ExecCheckRTEPerms(rte);
 341         }
 342 }
 343
 344 /*
 345  * ExecCheckRTEPerms
 346  *              Check access permissions for a single RTE.
 347  */
 348 static void
 349 ExecCheckRTEPerms(RangeTblEntry *rte)
 350 {
 351         AclMode         requiredPerms;
 352         Oid                     relOid;
 353         AclId           userid;
 354
 355         /*
 356          * Only plain-relation RTEs need to be checked here.  Subquery RTEs
 357          * are checked by ExecInitSubqueryScan if the subquery is still a
 358          * separate subquery --- if it's been pulled up into our query level
 359          * then the RTEs are in our rangetable and will be checked here.
 360          * Function RTEs are checked by init_fcache when the function is
 361          * prepared for execution. Join and special RTEs need no checks.
 362          */
 363         if (rte->rtekind != RTE_RELATION)
 364                 return;
 365
 366         /*
 367          * No work if requiredPerms is empty.
 368          */
 369         requiredPerms = rte->requiredPerms;
 370         if (requiredPerms == 0)
 371                 return;
 372
 373         relOid = rte->relid;
 374
 375         /*
 376          * userid to check as: current user unless we have a setuid
 377          * indication.
 378          *
 379          * Note: GetUserId() is presently fast enough that there's no harm in
 380          * calling it separately for each RTE.  If that stops being true, we
 381          * could call it once in ExecCheckRTPerms and pass the userid down
 382          * from there.  But for now, no need for the extra clutter.
 383          */
 384         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 385
 386         /*
 387          * We must have *all* the requiredPerms bits, so use aclmask not
 388          * aclcheck.
 389          */
 390         if (pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL)
 391                 != requiredPerms)
 392                 aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS,
 393                                            get_rel_name(relOid));
 394 }
 395
 396 /*
 397  * Check that the query does not imply any writes to non-temp tables.
 398  */
 399 static void
 400 ExecCheckXactReadOnly(Query *parsetree)
 401 {
 402         ListCell   *l;
 403
 404         /*
 405          * CREATE TABLE AS or SELECT INTO?
 406          *
 407          * XXX should we allow this if the destination is temp?
 408          */
 409         if (parsetree->into != NULL)
 410                 goto fail;
 411
 412         /* Fail if write permissions are requested on any non-temp table */
 413         foreach(l, parsetree->rtable)
 414         {
 415                 RangeTblEntry *rte = lfirst(l);
 416
 417                 if (rte->rtekind == RTE_SUBQUERY)
 418                 {
 419                         ExecCheckXactReadOnly(rte->subquery);
 420                         continue;
 421                 }
 422
 423                 if (rte->rtekind != RTE_RELATION)
 424                         continue;
 425
 426                 if ((rte->requiredPerms & (~ACL_SELECT)) == 0)
 427                         continue;
 428
 429                 if (isTempNamespace(get_rel_namespace(rte->relid)))
 430                         continue;
 431
 432                 goto fail;
 433         }
 434
 435         return;
 436
 437 fail:
 438         ereport(ERROR,
 439                         (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
 440                          errmsg("transaction is read-only")));
 441 }
 442
 443
 444 /* ----------------------------------------------------------------
 445  *              InitPlan
 446  *
 447  *              Initializes the query plan: open files, allocate storage
 448  *              and start up the rule manager
 449  * ----------------------------------------------------------------
 450  */
 451 static void
 452 InitPlan(QueryDesc *queryDesc, bool explainOnly)
 453 {
 454         CmdType         operation = queryDesc->operation;
 455         Query      *parseTree = queryDesc->parsetree;
 456         Plan       *plan = queryDesc->plantree;
 457         EState     *estate = queryDesc->estate;
 458         PlanState  *planstate;
 459         List       *rangeTable;
 460         Relation        intoRelationDesc;
 461         bool            do_select_into;
 462         TupleDesc       tupType;
 463
 464         /*
 465          * Do permissions checks.  It's sufficient to examine the query's top
 466          * rangetable here --- subplan RTEs will be checked during
 467          * ExecInitSubPlan().
 468          */
 469         ExecCheckRTPerms(parseTree->rtable);
 470
 471         /*
 472          * get information from query descriptor
 473          */
 474         rangeTable = parseTree->rtable;
 475
 476         /*
 477          * initialize the node's execution state
 478          */
 479         estate->es_range_table = rangeTable;
 480
 481         /*
 482          * if there is a result relation, initialize result relation stuff
 483          */
 484         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 485         {
 486                 List       *resultRelations = parseTree->resultRelations;
 487                 int                     numResultRelations;
 488                 ResultRelInfo *resultRelInfos;
 489
 490                 if (resultRelations != NIL)
 491                 {
 492                         /*
 493                          * Multiple result relations (due to inheritance)
 494                          * parseTree->resultRelations identifies them all
 495                          */
 496                         ResultRelInfo *resultRelInfo;
 497                         ListCell   *l;
 498
 499                         numResultRelations = list_length(resultRelations);
 500                         resultRelInfos = (ResultRelInfo *)
 501                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 502                         resultRelInfo = resultRelInfos;
 503                         foreach(l, resultRelations)
 504                         {
 505                                 initResultRelInfo(resultRelInfo,
 506                                                                   lfirst_int(l),
 507                                                                   rangeTable,
 508                                                                   operation,
 509                                                                   estate->es_instrument);
 510                                 resultRelInfo++;
 511                         }
 512                 }
 513                 else
 514                 {
 515                         /*
 516                          * Single result relation identified by
 517                          * parseTree->resultRelation
 518                          */
 519                         numResultRelations = 1;
 520                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 521                         initResultRelInfo(resultRelInfos,
 522                                                           parseTree->resultRelation,
 523                                                           rangeTable,
 524                                                           operation,
 525                                                           estate->es_instrument);
 526                 }
 527
 528                 estate->es_result_relations = resultRelInfos;
 529                 estate->es_num_result_relations = numResultRelations;
 530                 /* Initialize to first or only result rel */
 531                 estate->es_result_relation_info = resultRelInfos;
 532         }
 533         else
 534         {
 535                 /*
 536                  * if no result relation, then set state appropriately
 537                  */
 538                 estate->es_result_relations = NULL;
 539                 estate->es_num_result_relations = 0;
 540                 estate->es_result_relation_info = NULL;
 541         }
 542
 543         /*
 544          * Detect whether we're doing SELECT INTO.  If so, set the es_into_oids
 545          * flag appropriately so that the plan tree will be initialized with
 546          * the correct tuple descriptors.
 547          */
 548         do_select_into = false;
 549
 550         if (operation == CMD_SELECT && parseTree->into != NULL)
 551         {
 552                 do_select_into = true;
 553                 estate->es_select_into = true;
 554                 estate->es_into_oids = parseTree->intoHasOids;
 555         }
 556
 557         /*
 558          * Have to lock relations selected FOR UPDATE/FOR SHARE
 559          */
 560         estate->es_rowMark = NIL;
 561         estate->es_forUpdate = parseTree->forUpdate;
 562         if (parseTree->rowMarks != NIL)
 563         {
 564                 ListCell   *l;
 565
 566                 foreach(l, parseTree->rowMarks)
 567                 {
 568                         Index           rti = lfirst_int(l);
 569                         Oid                     relid = getrelid(rti, rangeTable);
 570                         Relation        relation;
 571                         execRowMark *erm;
 572
 573                         relation = heap_open(relid, RowShareLock);
 574                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 575                         erm->relation = relation;
 576                         erm->rti = rti;
 577                         snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
 578                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 579                 }
 580         }
 581
 582         /*
 583          * initialize the executor "tuple" table.  We need slots for all the
 584          * plan nodes, plus possibly output slots for the junkfilter(s). At
 585          * this point we aren't sure if we need junkfilters, so just add slots
 586          * for them unconditionally.
 587          */
 588         {
 589                 int                     nSlots = ExecCountSlotsNode(plan);
 590
 591                 if (parseTree->resultRelations != NIL)
 592                         nSlots += list_length(parseTree->resultRelations);
 593                 else
 594                         nSlots += 1;
 595                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 596         }
 597
 598         /* mark EvalPlanQual not active */
 599         estate->es_topPlan = plan;
 600         estate->es_evalPlanQual = NULL;
 601         estate->es_evTupleNull = NULL;
 602         estate->es_evTuple = NULL;
 603         estate->es_useEvalPlan = false;
 604
 605         /*
 606          * initialize the private state information for all the nodes in the
 607          * query tree.  This opens files, allocates storage and leaves us
 608          * ready to start processing tuples.
 609          */
 610         planstate = ExecInitNode(plan, estate);
 611
 612         /*
 613          * Get the tuple descriptor describing the type of tuples to return.
 614          * (this is especially important if we are creating a relation with
 615          * "SELECT INTO")
 616          */
 617         tupType = ExecGetResultType(planstate);
 618
 619         /*
 620          * Initialize the junk filter if needed.  SELECT and INSERT queries
 621          * need a filter if there are any junk attrs in the tlist.      INSERT and
 622          * SELECT INTO also need a filter if the plan may return raw disk
 623          * tuples (else heap_insert will be scribbling on the source
 624          * relation!). UPDATE and DELETE always need a filter, since there's
 625          * always a junk 'ctid' attribute present --- no need to look first.
 626          */
 627         {
 628                 bool            junk_filter_needed = false;
 629                 ListCell   *tlist;
 630
 631                 switch (operation)
 632                 {
 633                         case CMD_SELECT:
 634                         case CMD_INSERT:
 635                                 foreach(tlist, plan->targetlist)
 636                                 {
 637                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 638
 639                                         if (tle->resjunk)
 640                                         {
 641                                                 junk_filter_needed = true;
 642                                                 break;
 643                                         }
 644                                 }
 645                                 if (!junk_filter_needed &&
 646                                         (operation == CMD_INSERT || do_select_into) &&
 647                                         ExecMayReturnRawTuples(planstate))
 648                                         junk_filter_needed = true;
 649                                 break;
 650                         case CMD_UPDATE:
 651                         case CMD_DELETE:
 652                                 junk_filter_needed = true;
 653                                 break;
 654                         default:
 655                                 break;
 656                 }
 657
 658                 if (junk_filter_needed)
 659                 {
 660                         /*
 661                          * If there are multiple result relations, each one needs its
 662                          * own junk filter.  Note this is only possible for
 663                          * UPDATE/DELETE, so we can't be fooled by some needing a
 664                          * filter and some not.
 665                          */
 666                         if (parseTree->resultRelations != NIL)
 667                         {
 668                                 PlanState **appendplans;
 669                                 int                     as_nplans;
 670                                 ResultRelInfo *resultRelInfo;
 671                                 int                     i;
 672
 673                                 /* Top plan had better be an Append here. */
 674                                 Assert(IsA(plan, Append));
 675                                 Assert(((Append *) plan)->isTarget);
 676                                 Assert(IsA(planstate, AppendState));
 677                                 appendplans = ((AppendState *) planstate)->appendplans;
 678                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 679                                 Assert(as_nplans == estate->es_num_result_relations);
 680                                 resultRelInfo = estate->es_result_relations;
 681                                 for (i = 0; i < as_nplans; i++)
 682                                 {
 683                                         PlanState  *subplan = appendplans[i];
 684                                         JunkFilter *j;
 685
 686                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 687                                                                                    resultRelInfo->ri_RelationDesc->rd_att->tdhasoid,
 688                                                                                    ExecAllocTableSlot(estate->es_tupleTable));
 689                                         resultRelInfo->ri_junkFilter = j;
 690                                         resultRelInfo++;
 691                                 }
 692
 693                                 /*
 694                                  * Set active junkfilter too; at this point ExecInitAppend
 695                                  * has already selected an active result relation...
 696                                  */
 697                                 estate->es_junkFilter =
 698                                         estate->es_result_relation_info->ri_junkFilter;
 699                         }
 700                         else
 701                         {
 702                                 /* Normal case with just one JunkFilter */
 703                                 JunkFilter *j;
 704
 705                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 706                                                                            tupType->tdhasoid,
 707                                                           ExecAllocTableSlot(estate->es_tupleTable));
 708                                 estate->es_junkFilter = j;
 709                                 if (estate->es_result_relation_info)
 710                                         estate->es_result_relation_info->ri_junkFilter = j;
 711
 712                                 /* For SELECT, want to return the cleaned tuple type */
 713                                 if (operation == CMD_SELECT)
 714                                         tupType = j->jf_cleanTupType;
 715                         }
 716                 }
 717                 else
 718                         estate->es_junkFilter = NULL;
 719         }
 720
 721         /*
 722          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 723          * till now so we have the "clean" result tuple type to create the new
 724          * table from.
 725          *
 726          * If EXPLAIN, skip creating the "into" relation.
 727          */
 728         intoRelationDesc = NULL;
 729
 730         if (do_select_into && !explainOnly)
 731         {
 732                 char       *intoName;
 733                 Oid                     namespaceId;
 734                 AclResult       aclresult;
 735                 Oid                     intoRelationId;
 736                 TupleDesc       tupdesc;
 737
 738                 /*
 739                  * find namespace to create in, check permissions
 740                  */
 741                 intoName = parseTree->into->relname;
 742                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 743
 744                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 745                                                                                   ACL_CREATE);
 746                 if (aclresult != ACLCHECK_OK)
 747                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 748                                                    get_namespace_name(namespaceId));
 749
 750                 /*
 751                  * have to copy tupType to get rid of constraints
 752                  */
 753                 tupdesc = CreateTupleDescCopy(tupType);
 754
 755                 intoRelationId = heap_create_with_catalog(intoName,
 756                                                                                                   namespaceId,
 757                                                                                                   InvalidOid,
 758                                                                                                   InvalidOid,
 759                                                                                                   tupdesc,
 760                                                                                                   RELKIND_RELATION,
 761                                                                                                   false,
 762                                                                                                   true,
 763                                                                                                   0,
 764                                                                                                   ONCOMMIT_NOOP,
 765                                                                                                   allowSystemTableMods);
 766
 767                 FreeTupleDesc(tupdesc);
 768
 769                 /*
 770                  * Advance command counter so that the newly-created relation's
 771                  * catalog tuples will be visible to heap_open.
 772                  */
 773                 CommandCounterIncrement();
 774
 775                 /*
 776                  * If necessary, create a TOAST table for the into relation. Note
 777                  * that AlterTableCreateToastTable ends with
 778                  * CommandCounterIncrement(), so that the TOAST table will be
 779                  * visible for insertion.
 780                  */
 781                 AlterTableCreateToastTable(intoRelationId, true);
 782
 783                 /*
 784                  * And open the constructed table for writing.
 785                  */
 786                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 787         }
 788
 789         estate->es_into_relation_descriptor = intoRelationDesc;
 790
 791         queryDesc->tupDesc = tupType;
 792         queryDesc->planstate = planstate;
 793 }
 794
 795 /*
 796  * Initialize ResultRelInfo data for one result relation
 797  */
 798 static void
 799 initResultRelInfo(ResultRelInfo *resultRelInfo,
 800                                   Index resultRelationIndex,
 801                                   List *rangeTable,
 802                                   CmdType operation,
 803                                   bool doInstrument)
 804 {
 805         Oid                     resultRelationOid;
 806         Relation        resultRelationDesc;
 807
 808         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 809         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 810
 811         switch (resultRelationDesc->rd_rel->relkind)
 812         {
 813                 case RELKIND_SEQUENCE:
 814                         ereport(ERROR,
 815                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 816                                          errmsg("cannot change sequence \"%s\"",
 817                                                   RelationGetRelationName(resultRelationDesc))));
 818                         break;
 819                 case RELKIND_TOASTVALUE:
 820                         ereport(ERROR,
 821                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 822                                          errmsg("cannot change TOAST relation \"%s\"",
 823                                                   RelationGetRelationName(resultRelationDesc))));
 824                         break;
 825                 case RELKIND_VIEW:
 826                         ereport(ERROR,
 827                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 828                                          errmsg("cannot change view \"%s\"",
 829                                                   RelationGetRelationName(resultRelationDesc))));
 830                         break;
 831         }
 832
 833         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 834         resultRelInfo->type = T_ResultRelInfo;
 835         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 836         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 837         resultRelInfo->ri_NumIndices = 0;
 838         resultRelInfo->ri_IndexRelationDescs = NULL;
 839         resultRelInfo->ri_IndexRelationInfo = NULL;
 840         /* make a copy so as not to depend on relcache info not changing... */
 841         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 842         if (resultRelInfo->ri_TrigDesc)
 843         {
 844                 int             n = resultRelInfo->ri_TrigDesc->numtriggers;
 845
 846                 resultRelInfo->ri_TrigFunctions = (FmgrInfo *)
 847                         palloc0(n * sizeof(FmgrInfo));
 848                 if (doInstrument)
 849                         resultRelInfo->ri_TrigInstrument = InstrAlloc(n);
 850                 else
 851                         resultRelInfo->ri_TrigInstrument = NULL;
 852         }
 853         else
 854         {
 855                 resultRelInfo->ri_TrigFunctions = NULL;
 856                 resultRelInfo->ri_TrigInstrument = NULL;
 857         }
 858         resultRelInfo->ri_ConstraintExprs = NULL;
 859         resultRelInfo->ri_junkFilter = NULL;
 860
 861         /*
 862          * If there are indices on the result relation, open them and save
 863          * descriptors in the result relation info, so that we can add new
 864          * index entries for the tuples we add/update.  We need not do this
 865          * for a DELETE, however, since deletion doesn't affect indexes.
 866          */
 867         if (resultRelationDesc->rd_rel->relhasindex &&
 868                 operation != CMD_DELETE)
 869                 ExecOpenIndices(resultRelInfo);
 870 }
 871
 872 /*
 873  *              ExecContextForcesOids
 874  *
 875  * This is pretty grotty: when doing INSERT, UPDATE, or SELECT INTO,
 876  * we need to ensure that result tuples have space for an OID iff they are
 877  * going to be stored into a relation that has OIDs.  In other contexts
 878  * we are free to choose whether to leave space for OIDs in result tuples
 879  * (we generally don't want to, but we do if a physical-tlist optimization
 880  * is possible).  This routine checks the plan context and returns TRUE if the
 881  * choice is forced, FALSE if the choice is not forced.  In the TRUE case,
 882  * *hasoids is set to the required value.
 883  *
 884  * One reason this is ugly is that all plan nodes in the plan tree will emit
 885  * tuples with space for an OID, though we really only need the topmost node
 886  * to do so.  However, node types like Sort don't project new tuples but just
 887  * return their inputs, and in those cases the requirement propagates down
 888  * to the input node.  Eventually we might make this code smart enough to
 889  * recognize how far down the requirement really goes, but for now we just
 890  * make all plan nodes do the same thing if the top level forces the choice.
 891  *
 892  * We assume that estate->es_result_relation_info is already set up to
 893  * describe the target relation.  Note that in an UPDATE that spans an
 894  * inheritance tree, some of the target relations may have OIDs and some not.
 895  * We have to make the decisions on a per-relation basis as we initialize
 896  * each of the child plans of the topmost Append plan.
 897  *
 898  * SELECT INTO is even uglier, because we don't have the INTO relation's
 899  * descriptor available when this code runs; we have to look aside at a
 900  * flag set by InitPlan().
 901  */
 902 bool
 903 ExecContextForcesOids(PlanState *planstate, bool *hasoids)
 904 {
 905         if (planstate->state->es_select_into)
 906         {
 907                 *hasoids = planstate->state->es_into_oids;
 908                 return true;
 909         }
 910         else
 911         {
 912                 ResultRelInfo *ri = planstate->state->es_result_relation_info;
 913
 914                 if (ri != NULL)
 915                 {
 916                         Relation        rel = ri->ri_RelationDesc;
 917
 918                         if (rel != NULL)
 919                         {
 920                                 *hasoids = rel->rd_rel->relhasoids;
 921                                 return true;
 922                         }
 923                 }
 924         }
 925
 926         return false;
 927 }
 928
 929 /* ----------------------------------------------------------------
 930  *              ExecEndPlan
 931  *
 932  *              Cleans up the query plan -- closes files and frees up storage
 933  *
 934  * NOTE: we are no longer very worried about freeing storage per se
 935  * in this code; FreeExecutorState should be guaranteed to release all
 936  * memory that needs to be released.  What we are worried about doing
 937  * is closing relations and dropping buffer pins.  Thus, for example,
 938  * tuple tables must be cleared or dropped to ensure pins are released.
 939  * ----------------------------------------------------------------
 940  */
 941 void
 942 ExecEndPlan(PlanState *planstate, EState *estate)
 943 {
 944         ResultRelInfo *resultRelInfo;
 945         int                     i;
 946         ListCell   *l;
 947
 948         /*
 949          * shut down any PlanQual processing we were doing
 950          */
 951         if (estate->es_evalPlanQual != NULL)
 952                 EndEvalPlanQual(estate);
 953
 954         /*
 955          * shut down the node-type-specific query processing
 956          */
 957         ExecEndNode(planstate);
 958
 959         /*
 960          * destroy the executor "tuple" table.
 961          */
 962         ExecDropTupleTable(estate->es_tupleTable, true);
 963         estate->es_tupleTable = NULL;
 964
 965         /*
 966          * close the result relation(s) if any, but hold locks until xact
 967          * commit.
 968          */
 969         resultRelInfo = estate->es_result_relations;
 970         for (i = estate->es_num_result_relations; i > 0; i--)
 971         {
 972                 /* Close indices and then the relation itself */
 973                 ExecCloseIndices(resultRelInfo);
 974                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 975                 resultRelInfo++;
 976         }
 977
 978         /*
 979          * close the "into" relation if necessary, again keeping lock
 980          */
 981         if (estate->es_into_relation_descriptor != NULL)
 982                 heap_close(estate->es_into_relation_descriptor, NoLock);
 983
 984         /*
 985          * close any relations selected FOR UPDATE/FOR SHARE, again keeping locks
 986          */
 987         foreach(l, estate->es_rowMark)
 988         {
 989                 execRowMark *erm = lfirst(l);
 990
 991                 heap_close(erm->relation, NoLock);
 992         }
 993 }
 994
 995 /* ----------------------------------------------------------------
 996  *              ExecutePlan
 997  *
 998  *              processes the query plan to retrieve 'numberTuples' tuples in the
 999  *              direction specified.
1000  *
1001  *              Retrieves all tuples if numberTuples is 0
1002  *
1003  *              result is either a slot containing the last tuple in the case
1004  *              of a SELECT or NULL otherwise.
1005  *
1006  * Note: the ctid attribute is a 'junk' attribute that is removed before the
1007  * user can see it
1008  * ----------------------------------------------------------------
1009  */
1010 static TupleTableSlot *
1011 ExecutePlan(EState *estate,
1012                         PlanState *planstate,
1013                         CmdType operation,
1014                         long numberTuples,
1015                         ScanDirection direction,
1016                         DestReceiver *dest)
1017 {
1018         JunkFilter *junkfilter;
1019         TupleTableSlot *slot;
1020         ItemPointer tupleid = NULL;
1021         ItemPointerData tuple_ctid;
1022         long            current_tuple_count;
1023         TupleTableSlot *result;
1024
1025         /*
1026          * initialize local variables
1027          */
1028         slot = NULL;
1029         current_tuple_count = 0;
1030         result = NULL;
1031
1032         /*
1033          * Set the direction.
1034          */
1035         estate->es_direction = direction;
1036
1037         /*
1038          * Process BEFORE EACH STATEMENT triggers
1039          */
1040         switch (operation)
1041         {
1042                 case CMD_UPDATE:
1043                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
1044                         break;
1045                 case CMD_DELETE:
1046                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1047                         break;
1048                 case CMD_INSERT:
1049                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1050                         break;
1051                 default:
1052                         /* do nothing */
1053                         break;
1054         }
1055
1056         /*
1057          * Loop until we've processed the proper number of tuples from the
1058          * plan.
1059          */
1060
1061         for (;;)
1062         {
1063                 /* Reset the per-output-tuple exprcontext */
1064                 ResetPerTupleExprContext(estate);
1065
1066                 /*
1067                  * Execute the plan and obtain a tuple
1068                  */
1069 lnext:  ;
1070                 if (estate->es_useEvalPlan)
1071                 {
1072                         slot = EvalPlanQualNext(estate);
1073                         if (TupIsNull(slot))
1074                                 slot = ExecProcNode(planstate);
1075                 }
1076                 else
1077                         slot = ExecProcNode(planstate);
1078
1079                 /*
1080                  * if the tuple is null, then we assume there is nothing more to
1081                  * process so we just return null...
1082                  */
1083                 if (TupIsNull(slot))
1084                 {
1085                         result = NULL;
1086                         break;
1087                 }
1088
1089                 /*
1090                  * if we have a junk filter, then project a new tuple with the
1091                  * junk removed.
1092                  *
1093                  * Store this new "clean" tuple in the junkfilter's resultSlot.
1094                  * (Formerly, we stored it back over the "dirty" tuple, which is
1095                  * WRONG because that tuple slot has the wrong descriptor.)
1096                  *
1097                  * Also, extract all the junk information we need.
1098                  */
1099                 if ((junkfilter = estate->es_junkFilter) != NULL)
1100                 {
1101                         Datum           datum;
1102                         bool            isNull;
1103
1104                         /*
1105                          * extract the 'ctid' junk attribute.
1106                          */
1107                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1108                         {
1109                                 if (!ExecGetJunkAttribute(junkfilter,
1110                                                                                   slot,
1111                                                                                   "ctid",
1112                                                                                   &datum,
1113                                                                                   &isNull))
1114                                         elog(ERROR, "could not find junk ctid column");
1115
1116                                 /* shouldn't ever get a null result... */
1117                                 if (isNull)
1118                                         elog(ERROR, "ctid is NULL");
1119
1120                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1121                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1122                                                                                  * ctid!! */
1123                                 tupleid = &tuple_ctid;
1124                         }
1125                         /*
1126                          * Process any FOR UPDATE or FOR SHARE locking requested.
1127                          */
1128                         else if (estate->es_rowMark != NIL)
1129                         {
1130                                 ListCell   *l;
1131
1132                 lmark:  ;
1133                                 foreach(l, estate->es_rowMark)
1134                                 {
1135                                         execRowMark *erm = lfirst(l);
1136                                         Buffer          buffer;
1137                                         HeapTupleData tuple;
1138                                         TupleTableSlot *newSlot;
1139                                         LockTupleMode   lockmode;
1140                                         HTSU_Result             test;
1141
1142                                         if (!ExecGetJunkAttribute(junkfilter,
1143                                                                                           slot,
1144                                                                                           erm->resname,
1145                                                                                           &datum,
1146                                                                                           &isNull))
1147                                                 elog(ERROR, "could not find junk \"%s\" column",
1148                                                          erm->resname);
1149
1150                                         /* shouldn't ever get a null result... */
1151                                         if (isNull)
1152                                                 elog(ERROR, "\"%s\" is NULL", erm->resname);
1153
1154                                         if (estate->es_forUpdate)
1155                                                 lockmode = LockTupleExclusive;
1156                                         else
1157                                                 lockmode = LockTupleShared;
1158
1159                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1160                                         test = heap_lock_tuple(erm->relation, &tuple, &buffer,
1161                                                                                   estate->es_snapshot->curcid,
1162                                                                                   lockmode);
1163                                         ReleaseBuffer(buffer);
1164                                         switch (test)
1165                                         {
1166                                                 case HeapTupleSelfUpdated:
1167                                                         /* treat it as deleted; do not process */
1168                                                         goto lnext;
1169
1170                                                 case HeapTupleMayBeUpdated:
1171                                                         break;
1172
1173                                                 case HeapTupleUpdated:
1174                                                         if (IsXactIsoLevelSerializable)
1175                                                                 ereport(ERROR,
1176                                                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1177                                                                                  errmsg("could not serialize access due to concurrent update")));
1178                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1179                                                                   (ItemPointer) DatumGetPointer(datum))))
1180                                                         {
1181                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1182                                                                 if (!(TupIsNull(newSlot)))
1183                                                                 {
1184                                                                         slot = newSlot;
1185                                                                         estate->es_useEvalPlan = true;
1186                                                                         goto lmark;
1187                                                                 }
1188                                                         }
1189
1190                                                         /*
1191                                                          * if tuple was deleted or PlanQual failed for
1192                                                          * updated tuple - we must not return this
1193                                                          * tuple!
1194                                                          */
1195                                                         goto lnext;
1196
1197                                                 default:
1198                                                         elog(ERROR, "unrecognized heap_lock_tuple status: %u",
1199                                                                  test);
1200                                                         return (NULL);
1201                                         }
1202                                 }
1203                         }
1204
1205                         /*
1206                          * Finally create a new "clean" tuple with all junk attributes
1207                          * removed
1208                          */
1209                         slot = ExecFilterJunk(junkfilter, slot);
1210                 }
1211
1212                 /*
1213                  * now that we have a tuple, do the appropriate thing with it..
1214                  * either return it to the user, add it to a relation someplace,
1215                  * delete it from a relation, or modify some of its attributes.
1216                  */
1217                 switch (operation)
1218                 {
1219                         case CMD_SELECT:
1220                                 ExecSelect(slot,        /* slot containing tuple */
1221                                                    dest,        /* destination's tuple-receiver obj */
1222                                                    estate);
1223                                 result = slot;
1224                                 break;
1225
1226                         case CMD_INSERT:
1227                                 ExecInsert(slot, tupleid, estate);
1228                                 result = NULL;
1229                                 break;
1230
1231                         case CMD_DELETE:
1232                                 ExecDelete(slot, tupleid, estate);
1233                                 result = NULL;
1234                                 break;
1235
1236                         case CMD_UPDATE:
1237                                 ExecUpdate(slot, tupleid, estate);
1238                                 result = NULL;
1239                                 break;
1240
1241                         default:
1242                                 elog(ERROR, "unrecognized operation code: %d",
1243                                          (int) operation);
1244                                 result = NULL;
1245                                 break;
1246                 }
1247
1248                 /*
1249                  * check our tuple count.. if we've processed the proper number
1250                  * then quit, else loop again and process more tuples.  Zero
1251                  * numberTuples means no limit.
1252                  */
1253                 current_tuple_count++;
1254                 if (numberTuples && numberTuples == current_tuple_count)
1255                         break;
1256         }
1257
1258         /*
1259          * Process AFTER EACH STATEMENT triggers
1260          */
1261         switch (operation)
1262         {
1263                 case CMD_UPDATE:
1264                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1265                         break;
1266                 case CMD_DELETE:
1267                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1268                         break;
1269                 case CMD_INSERT:
1270                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1271                         break;
1272                 default:
1273                         /* do nothing */
1274                         break;
1275         }
1276
1277         /*
1278          * here, result is either a slot containing a tuple in the case of a
1279          * SELECT or NULL otherwise.
1280          */
1281         return result;
1282 }
1283
1284 /* ----------------------------------------------------------------
1285  *              ExecSelect
1286  *
1287  *              SELECTs are easy.. we just pass the tuple to the appropriate
1288  *              print function.  The only complexity is when we do a
1289  *              "SELECT INTO", in which case we insert the tuple into
1290  *              the appropriate relation (note: this is a newly created relation
1291  *              so we don't need to worry about indices or locks.)
1292  * ----------------------------------------------------------------
1293  */
1294 static void
1295 ExecSelect(TupleTableSlot *slot,
1296                    DestReceiver *dest,
1297                    EState *estate)
1298 {
1299         /*
1300          * insert the tuple into the "into relation"
1301          *
1302          * XXX this probably ought to be replaced by a separate destination
1303          */
1304         if (estate->es_into_relation_descriptor != NULL)
1305         {
1306                 HeapTuple       tuple;
1307
1308                 tuple = ExecCopySlotTuple(slot);
1309                 heap_insert(estate->es_into_relation_descriptor, tuple,
1310                                         estate->es_snapshot->curcid);
1311                 /* we know there are no indexes to update */
1312                 heap_freetuple(tuple);
1313                 IncrAppended();
1314         }
1315
1316         /*
1317          * send the tuple to the destination
1318          */
1319         (*dest->receiveSlot) (slot, dest);
1320         IncrRetrieved();
1321         (estate->es_processed)++;
1322 }
1323
1324 /* ----------------------------------------------------------------
1325  *              ExecInsert
1326  *
1327  *              INSERTs are trickier.. we have to insert the tuple into
1328  *              the base relation and insert appropriate tuples into the
1329  *              index relations.
1330  * ----------------------------------------------------------------
1331  */
1332 static void
1333 ExecInsert(TupleTableSlot *slot,
1334                    ItemPointer tupleid,
1335                    EState *estate)
1336 {
1337         HeapTuple       tuple;
1338         ResultRelInfo *resultRelInfo;
1339         Relation        resultRelationDesc;
1340         int                     numIndices;
1341         Oid                     newId;
1342
1343         /*
1344          * get the heap tuple out of the tuple table slot, making sure
1345          * we have a writable copy
1346          */
1347         tuple = ExecMaterializeSlot(slot);
1348
1349         /*
1350          * get information on the (current) result relation
1351          */
1352         resultRelInfo = estate->es_result_relation_info;
1353         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1354
1355         /* BEFORE ROW INSERT Triggers */
1356         if (resultRelInfo->ri_TrigDesc &&
1357           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1358         {
1359                 HeapTuple       newtuple;
1360
1361                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1362
1363                 if (newtuple == NULL)   /* "do nothing" */
1364                         return;
1365
1366                 if (newtuple != tuple)  /* modified by Trigger(s) */
1367                 {
1368                         /*
1369                          * Insert modified tuple into tuple table slot, replacing the
1370                          * original.  We assume that it was allocated in per-tuple
1371                          * memory context, and therefore will go away by itself. The
1372                          * tuple table slot should not try to clear it.
1373                          */
1374                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1375                         tuple = newtuple;
1376                 }
1377         }
1378
1379         /*
1380          * Check the constraints of the tuple
1381          */
1382         if (resultRelationDesc->rd_att->constr)
1383                 ExecConstraints(resultRelInfo, slot, estate);
1384
1385         /*
1386          * insert the tuple
1387          */
1388         newId = heap_insert(resultRelationDesc, tuple,
1389                                                 estate->es_snapshot->curcid);
1390
1391         IncrAppended();
1392         (estate->es_processed)++;
1393         estate->es_lastoid = newId;
1394         setLastTid(&(tuple->t_self));
1395
1396         /*
1397          * process indices
1398          *
1399          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1400          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1401          * field.
1402          */
1403         numIndices = resultRelInfo->ri_NumIndices;
1404         if (numIndices > 0)
1405                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1406
1407         /* AFTER ROW INSERT Triggers */
1408         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1409 }
1410
1411 /* ----------------------------------------------------------------
1412  *              ExecDelete
1413  *
1414  *              DELETE is like UPDATE, we delete the tuple and its
1415  *              index tuples.
1416  * ----------------------------------------------------------------
1417  */
1418 static void
1419 ExecDelete(TupleTableSlot *slot,
1420                    ItemPointer tupleid,
1421                    EState *estate)
1422 {
1423         ResultRelInfo *resultRelInfo;
1424         Relation        resultRelationDesc;
1425         ItemPointerData ctid;
1426         HTSU_Result     result;
1427
1428         /*
1429          * get information on the (current) result relation
1430          */
1431         resultRelInfo = estate->es_result_relation_info;
1432         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1433
1434         /* BEFORE ROW DELETE Triggers */
1435         if (resultRelInfo->ri_TrigDesc &&
1436           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1437         {
1438                 bool            dodelete;
1439
1440                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1441                                                                                 estate->es_snapshot->curcid);
1442
1443                 if (!dodelete)                  /* "do nothing" */
1444                         return;
1445         }
1446
1447         /*
1448          * delete the tuple
1449          *
1450          * Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check that
1451          * the row to be deleted is visible to that snapshot, and throw a can't-
1452          * serialize error if not.  This is a special-case behavior needed for
1453          * referential integrity updates in serializable transactions.
1454          */
1455 ldelete:;
1456         result = heap_delete(resultRelationDesc, tupleid,
1457                                                  &ctid,
1458                                                  estate->es_snapshot->curcid,
1459                                                  estate->es_crosscheck_snapshot,
1460                                                  true /* wait for commit */ );
1461         switch (result)
1462         {
1463                 case HeapTupleSelfUpdated:
1464                         /* already deleted by self; nothing to do */
1465                         return;
1466
1467                 case HeapTupleMayBeUpdated:
1468                         break;
1469
1470                 case HeapTupleUpdated:
1471                         if (IsXactIsoLevelSerializable)
1472                                 ereport(ERROR,
1473                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1474                                                  errmsg("could not serialize access due to concurrent update")));
1475                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1476                         {
1477                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1478                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1479
1480                                 if (!TupIsNull(epqslot))
1481                                 {
1482                                         *tupleid = ctid;
1483                                         goto ldelete;
1484                                 }
1485                         }
1486                         /* tuple already deleted; nothing to do */
1487                         return;
1488
1489                 default:
1490                         elog(ERROR, "unrecognized heap_delete status: %u", result);
1491                         return;
1492         }
1493
1494         IncrDeleted();
1495         (estate->es_processed)++;
1496
1497         /*
1498          * Note: Normally one would think that we have to delete index tuples
1499          * associated with the heap tuple now..
1500          *
1501          * ... but in POSTGRES, we have no need to do this because the vacuum
1502          * daemon automatically opens an index scan and deletes index tuples
1503          * when it finds deleted heap tuples. -cim 9/27/89
1504          */
1505
1506         /* AFTER ROW DELETE Triggers */
1507         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1508 }
1509
1510 /* ----------------------------------------------------------------
1511  *              ExecUpdate
1512  *
1513  *              note: we can't run UPDATE queries with transactions
1514  *              off because UPDATEs are actually INSERTs and our
1515  *              scan will mistakenly loop forever, updating the tuple
1516  *              it just inserted..      This should be fixed but until it
1517  *              is, we don't want to get stuck in an infinite loop
1518  *              which corrupts your database..
1519  * ----------------------------------------------------------------
1520  */
1521 static void
1522 ExecUpdate(TupleTableSlot *slot,
1523                    ItemPointer tupleid,
1524                    EState *estate)
1525 {
1526         HeapTuple       tuple;
1527         ResultRelInfo *resultRelInfo;
1528         Relation        resultRelationDesc;
1529         ItemPointerData ctid;
1530         HTSU_Result     result;
1531         int                     numIndices;
1532
1533         /*
1534          * abort the operation if not running transactions
1535          */
1536         if (IsBootstrapProcessingMode())
1537                 elog(ERROR, "cannot UPDATE during bootstrap");
1538
1539         /*
1540          * get the heap tuple out of the tuple table slot, making sure
1541          * we have a writable copy
1542          */
1543         tuple = ExecMaterializeSlot(slot);
1544
1545         /*
1546          * get information on the (current) result relation
1547          */
1548         resultRelInfo = estate->es_result_relation_info;
1549         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1550
1551         /* BEFORE ROW UPDATE Triggers */
1552         if (resultRelInfo->ri_TrigDesc &&
1553           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1554         {
1555                 HeapTuple       newtuple;
1556
1557                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1558                                                                                 tupleid, tuple,
1559                                                                                 estate->es_snapshot->curcid);
1560
1561                 if (newtuple == NULL)   /* "do nothing" */
1562                         return;
1563
1564                 if (newtuple != tuple)  /* modified by Trigger(s) */
1565                 {
1566                         /*
1567                          * Insert modified tuple into tuple table slot, replacing the
1568                          * original.  We assume that it was allocated in per-tuple
1569                          * memory context, and therefore will go away by itself. The
1570                          * tuple table slot should not try to clear it.
1571                          */
1572                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1573                         tuple = newtuple;
1574                 }
1575         }
1576
1577         /*
1578          * Check the constraints of the tuple
1579          *
1580          * If we generate a new candidate tuple after EvalPlanQual testing, we
1581          * must loop back here and recheck constraints.  (We don't need to
1582          * redo triggers, however.      If there are any BEFORE triggers then
1583          * trigger.c will have done heap_lock_tuple to lock the correct tuple,
1584          * so there's no need to do them again.)
1585          */
1586 lreplace:;
1587         if (resultRelationDesc->rd_att->constr)
1588                 ExecConstraints(resultRelInfo, slot, estate);
1589
1590         /*
1591          * replace the heap tuple
1592          *
1593          * Note: if es_crosscheck_snapshot isn't InvalidSnapshot, we check that
1594          * the row to be updated is visible to that snapshot, and throw a can't-
1595          * serialize error if not.  This is a special-case behavior needed for
1596          * referential integrity updates in serializable transactions.
1597          */
1598         result = heap_update(resultRelationDesc, tupleid, tuple,
1599                                                  &ctid,
1600                                                  estate->es_snapshot->curcid,
1601                                                  estate->es_crosscheck_snapshot,
1602                                                  true /* wait for commit */ );
1603         switch (result)
1604         {
1605                 case HeapTupleSelfUpdated:
1606                         /* already deleted by self; nothing to do */
1607                         return;
1608
1609                 case HeapTupleMayBeUpdated:
1610                         break;
1611
1612                 case HeapTupleUpdated:
1613                         if (IsXactIsoLevelSerializable)
1614                                 ereport(ERROR,
1615                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1616                                                  errmsg("could not serialize access due to concurrent update")));
1617                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1618                         {
1619                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1620                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1621
1622                                 if (!TupIsNull(epqslot))
1623                                 {
1624                                         *tupleid = ctid;
1625                                         slot = ExecFilterJunk(estate->es_junkFilter, epqslot);
1626                                         tuple = ExecMaterializeSlot(slot);
1627                                         goto lreplace;
1628                                 }
1629                         }
1630                         /* tuple already deleted; nothing to do */
1631                         return;
1632
1633                 default:
1634                         elog(ERROR, "unrecognized heap_update status: %u", result);
1635                         return;
1636         }
1637
1638         IncrReplaced();
1639         (estate->es_processed)++;
1640
1641         /*
1642          * Note: instead of having to update the old index tuples associated
1643          * with the heap tuple, all we do is form and insert new index tuples.
1644          * This is because UPDATEs are actually DELETEs and INSERTs and index
1645          * tuple deletion is done automagically by the vacuum daemon. All we
1646          * do is insert new index tuples.  -cim 9/27/89
1647          */
1648
1649         /*
1650          * process indices
1651          *
1652          * heap_update updates a tuple in the base relation by invalidating it
1653          * and then inserting a new tuple to the relation.      As a side effect,
1654          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1655          * field.  So we now insert index tuples using the new tupleid stored
1656          * there.
1657          */
1658
1659         numIndices = resultRelInfo->ri_NumIndices;
1660         if (numIndices > 0)
1661                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1662
1663         /* AFTER ROW UPDATE Triggers */
1664         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1665 }
1666
1667 static const char *
1668 ExecRelCheck(ResultRelInfo *resultRelInfo,
1669                          TupleTableSlot *slot, EState *estate)
1670 {
1671         Relation        rel = resultRelInfo->ri_RelationDesc;
1672         int                     ncheck = rel->rd_att->constr->num_check;
1673         ConstrCheck *check = rel->rd_att->constr->check;
1674         ExprContext *econtext;
1675         MemoryContext oldContext;
1676         List       *qual;
1677         int                     i;
1678
1679         /*
1680          * If first time through for this result relation, build expression
1681          * nodetrees for rel's constraint expressions.  Keep them in the
1682          * per-query memory context so they'll survive throughout the query.
1683          */
1684         if (resultRelInfo->ri_ConstraintExprs == NULL)
1685         {
1686                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1687                 resultRelInfo->ri_ConstraintExprs =
1688                         (List **) palloc(ncheck * sizeof(List *));
1689                 for (i = 0; i < ncheck; i++)
1690                 {
1691                         /* ExecQual wants implicit-AND form */
1692                         qual = make_ands_implicit(stringToNode(check[i].ccbin));
1693                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1694                                 ExecPrepareExpr((Expr *) qual, estate);
1695                 }
1696                 MemoryContextSwitchTo(oldContext);
1697         }
1698
1699         /*
1700          * We will use the EState's per-tuple context for evaluating
1701          * constraint expressions (creating it if it's not already there).
1702          */
1703         econtext = GetPerTupleExprContext(estate);
1704
1705         /* Arrange for econtext's scan tuple to be the tuple under test */
1706         econtext->ecxt_scantuple = slot;
1707
1708         /* And evaluate the constraints */
1709         for (i = 0; i < ncheck; i++)
1710         {
1711                 qual = resultRelInfo->ri_ConstraintExprs[i];
1712
1713                 /*
1714                  * NOTE: SQL92 specifies that a NULL result from a constraint
1715                  * expression is not to be treated as a failure.  Therefore, tell
1716                  * ExecQual to return TRUE for NULL.
1717                  */
1718                 if (!ExecQual(qual, econtext, true))
1719                         return check[i].ccname;
1720         }
1721
1722         /* NULL result means no error */
1723         return NULL;
1724 }
1725
1726 void
1727 ExecConstraints(ResultRelInfo *resultRelInfo,
1728                                 TupleTableSlot *slot, EState *estate)
1729 {
1730         Relation        rel = resultRelInfo->ri_RelationDesc;
1731         TupleConstr *constr = rel->rd_att->constr;
1732
1733         Assert(constr);
1734
1735         if (constr->has_not_null)
1736         {
1737                 int                     natts = rel->rd_att->natts;
1738                 int                     attrChk;
1739
1740                 for (attrChk = 1; attrChk <= natts; attrChk++)
1741                 {
1742                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1743                                 slot_attisnull(slot, attrChk))
1744                                 ereport(ERROR,
1745                                                 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1746                                                  errmsg("null value in column \"%s\" violates not-null constraint",
1747                                         NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1748                 }
1749         }
1750
1751         if (constr->num_check > 0)
1752         {
1753                 const char *failed;
1754
1755                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1756                         ereport(ERROR,
1757                                         (errcode(ERRCODE_CHECK_VIOLATION),
1758                                          errmsg("new row for relation \"%s\" violates check constraint \"%s\"",
1759                                                         RelationGetRelationName(rel), failed)));
1760         }
1761 }
1762
1763 /*
1764  * Check a modified tuple to see if we want to process its updated version
1765  * under READ COMMITTED rules.
1766  *
1767  * See backend/executor/README for some info about how this works.
1768  */
1769 TupleTableSlot *
1770 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1771 {
1772         evalPlanQual *epq;
1773         EState     *epqstate;
1774         Relation        relation;
1775         HeapTupleData tuple;
1776         HeapTuple       copyTuple = NULL;
1777         bool            endNode;
1778
1779         Assert(rti != 0);
1780
1781         /*
1782          * find relation containing target tuple
1783          */
1784         if (estate->es_result_relation_info != NULL &&
1785                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1786                 relation = estate->es_result_relation_info->ri_RelationDesc;
1787         else
1788         {
1789                 ListCell   *l;
1790
1791                 relation = NULL;
1792                 foreach(l, estate->es_rowMark)
1793                 {
1794                         if (((execRowMark *) lfirst(l))->rti == rti)
1795                         {
1796                                 relation = ((execRowMark *) lfirst(l))->relation;
1797                                 break;
1798                         }
1799                 }
1800                 if (relation == NULL)
1801                         elog(ERROR, "could not find RowMark for RT index %u", rti);
1802         }
1803
1804         /*
1805          * fetch tid tuple
1806          *
1807          * Loop here to deal with updated or busy tuples
1808          */
1809         tuple.t_self = *tid;
1810         for (;;)
1811         {
1812                 Buffer          buffer;
1813
1814                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1815                 {
1816                         TransactionId xwait = SnapshotDirty->xmax;
1817
1818                         /* xmin should not be dirty... */
1819                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1820                                 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1821
1822                         /*
1823                          * If tuple is being updated by other transaction then we have
1824                          * to wait for its commit/abort.
1825                          */
1826                         if (TransactionIdIsValid(xwait))
1827                         {
1828                                 ReleaseBuffer(buffer);
1829                                 XactLockTableWait(xwait);
1830                                 continue;
1831                         }
1832
1833                         /*
1834                          * We got tuple - now copy it for use by recheck query.
1835                          */
1836                         copyTuple = heap_copytuple(&tuple);
1837                         ReleaseBuffer(buffer);
1838                         break;
1839                 }
1840
1841                 /*
1842                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1843                  * Note that it's possible to get invalid SnapshotDirty->tid if
1844                  * tuple updated by this transaction. Have we to check this ?
1845                  */
1846                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1847                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1848                 {
1849                         /* updated, so look at the updated copy */
1850                         tuple.t_self = SnapshotDirty->tid;
1851                         continue;
1852                 }
1853
1854                 /*
1855                  * Deleted or updated by this transaction; forget it.
1856                  */
1857                 return NULL;
1858         }
1859
1860         /*
1861          * For UPDATE/DELETE we have to return tid of actual row we're
1862          * executing PQ for.
1863          */
1864         *tid = tuple.t_self;
1865
1866         /*
1867          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1868          */
1869         epq = estate->es_evalPlanQual;
1870         endNode = true;
1871
1872         if (epq != NULL && epq->rti == 0)
1873         {
1874                 /* Top PQ stack entry is idle, so re-use it */
1875                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1876                 epq->rti = rti;
1877                 endNode = false;
1878         }
1879
1880         /*
1881          * If this is request for another RTE - Ra, - then we have to check
1882          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1883          * updated again and we have to re-start old execution for Ra and
1884          * forget all what we done after Ra was suspended. Cool? -:))
1885          */
1886         if (epq != NULL && epq->rti != rti &&
1887                 epq->estate->es_evTuple[rti - 1] != NULL)
1888         {
1889                 do
1890                 {
1891                         evalPlanQual *oldepq;
1892
1893                         /* stop execution */
1894                         EvalPlanQualStop(epq);
1895                         /* pop previous PlanQual from the stack */
1896                         oldepq = epq->next;
1897                         Assert(oldepq && oldepq->rti != 0);
1898                         /* push current PQ to freePQ stack */
1899                         oldepq->free = epq;
1900                         epq = oldepq;
1901                         estate->es_evalPlanQual = epq;
1902                 } while (epq->rti != rti);
1903         }
1904
1905         /*
1906          * If we are requested for another RTE then we have to suspend
1907          * execution of current PlanQual and start execution for new one.
1908          */
1909         if (epq == NULL || epq->rti != rti)
1910         {
1911                 /* try to reuse plan used previously */
1912                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1913
1914                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1915                 {
1916                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1917                         newepq->free = NULL;
1918                         newepq->estate = NULL;
1919                         newepq->planstate = NULL;
1920                 }
1921                 else
1922                 {
1923                         /* recycle previously used PlanQual */
1924                         Assert(newepq->estate == NULL);
1925                         epq->free = NULL;
1926                 }
1927                 /* push current PQ to the stack */
1928                 newepq->next = epq;
1929                 epq = newepq;
1930                 estate->es_evalPlanQual = epq;
1931                 epq->rti = rti;
1932                 endNode = false;
1933         }
1934
1935         Assert(epq->rti == rti);
1936
1937         /*
1938          * Ok - we're requested for the same RTE.  Unfortunately we still have
1939          * to end and restart execution of the plan, because ExecReScan
1940          * wouldn't ensure that upper plan nodes would reset themselves.  We
1941          * could make that work if insertion of the target tuple were
1942          * integrated with the Param mechanism somehow, so that the upper plan
1943          * nodes know that their children's outputs have changed.
1944          *
1945          * Note that the stack of free evalPlanQual nodes is quite useless at the
1946          * moment, since it only saves us from pallocing/releasing the
1947          * evalPlanQual nodes themselves.  But it will be useful once we
1948          * implement ReScan instead of end/restart for re-using PlanQual
1949          * nodes.
1950          */
1951         if (endNode)
1952         {
1953                 /* stop execution */
1954                 EvalPlanQualStop(epq);
1955         }
1956
1957         /*
1958          * Initialize new recheck query.
1959          *
1960          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to
1961          * instead copy down changeable state from the top plan (including
1962          * es_result_relation_info, es_junkFilter) and reset locally
1963          * changeable state in the epq (including es_param_exec_vals,
1964          * es_evTupleNull).
1965          */
1966         EvalPlanQualStart(epq, estate, epq->next);
1967
1968         /*
1969          * free old RTE' tuple, if any, and store target tuple where
1970          * relation's scan node will see it
1971          */
1972         epqstate = epq->estate;
1973         if (epqstate->es_evTuple[rti - 1] != NULL)
1974                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1975         epqstate->es_evTuple[rti - 1] = copyTuple;
1976
1977         return EvalPlanQualNext(estate);
1978 }
1979
1980 static TupleTableSlot *
1981 EvalPlanQualNext(EState *estate)
1982 {
1983         evalPlanQual *epq = estate->es_evalPlanQual;
1984         MemoryContext oldcontext;
1985         TupleTableSlot *slot;
1986
1987         Assert(epq->rti != 0);
1988
1989 lpqnext:;
1990         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1991         slot = ExecProcNode(epq->planstate);
1992         MemoryContextSwitchTo(oldcontext);
1993
1994         /*
1995          * No more tuples for this PQ. Continue previous one.
1996          */
1997         if (TupIsNull(slot))
1998         {
1999                 evalPlanQual *oldepq;
2000
2001                 /* stop execution */
2002                 EvalPlanQualStop(epq);
2003                 /* pop old PQ from the stack */
2004                 oldepq = epq->next;
2005                 if (oldepq == NULL)
2006                 {
2007                         /* this is the first (oldest) PQ - mark as free */
2008                         epq->rti = 0;
2009                         estate->es_useEvalPlan = false;
2010                         /* and continue Query execution */
2011                         return (NULL);
2012                 }
2013                 Assert(oldepq->rti != 0);
2014                 /* push current PQ to freePQ stack */
2015                 oldepq->free = epq;
2016                 epq = oldepq;
2017                 estate->es_evalPlanQual = epq;
2018                 goto lpqnext;
2019         }
2020
2021         return (slot);
2022 }
2023
2024 static void
2025 EndEvalPlanQual(EState *estate)
2026 {
2027         evalPlanQual *epq = estate->es_evalPlanQual;
2028
2029         if (epq->rti == 0)                      /* plans already shutdowned */
2030         {
2031                 Assert(epq->next == NULL);
2032                 return;
2033         }
2034
2035         for (;;)
2036         {
2037                 evalPlanQual *oldepq;
2038
2039                 /* stop execution */
2040                 EvalPlanQualStop(epq);
2041                 /* pop old PQ from the stack */
2042                 oldepq = epq->next;
2043                 if (oldepq == NULL)
2044                 {
2045                         /* this is the first (oldest) PQ - mark as free */
2046                         epq->rti = 0;
2047                         estate->es_useEvalPlan = false;
2048                         break;
2049                 }
2050                 Assert(oldepq->rti != 0);
2051                 /* push current PQ to freePQ stack */
2052                 oldepq->free = epq;
2053                 epq = oldepq;
2054                 estate->es_evalPlanQual = epq;
2055         }
2056 }
2057
2058 /*
2059  * Start execution of one level of PlanQual.
2060  *
2061  * This is a cut-down version of ExecutorStart(): we copy some state from
2062  * the top-level estate rather than initializing it fresh.
2063  */
2064 static void
2065 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2066 {
2067         EState     *epqstate;
2068         int                     rtsize;
2069         MemoryContext oldcontext;
2070
2071         rtsize = list_length(estate->es_range_table);
2072
2073         epq->estate = epqstate = CreateExecutorState();
2074
2075         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2076
2077         /*
2078          * The epqstates share the top query's copy of unchanging state such
2079          * as the snapshot, rangetable, result-rel info, and external Param
2080          * info. They need their own copies of local state, including a tuple
2081          * table, es_param_exec_vals, etc.
2082          */
2083         epqstate->es_direction = ForwardScanDirection;
2084         epqstate->es_snapshot = estate->es_snapshot;
2085         epqstate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
2086         epqstate->es_range_table = estate->es_range_table;
2087         epqstate->es_result_relations = estate->es_result_relations;
2088         epqstate->es_num_result_relations = estate->es_num_result_relations;
2089         epqstate->es_result_relation_info = estate->es_result_relation_info;
2090         epqstate->es_junkFilter = estate->es_junkFilter;
2091         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2092         epqstate->es_param_list_info = estate->es_param_list_info;
2093         if (estate->es_topPlan->nParamExec > 0)
2094                 epqstate->es_param_exec_vals = (ParamExecData *)
2095                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2096         epqstate->es_rowMark = estate->es_rowMark;
2097         epqstate->es_forUpdate = estate->es_forUpdate;
2098         epqstate->es_instrument = estate->es_instrument;
2099         epqstate->es_select_into = estate->es_select_into;
2100         epqstate->es_into_oids = estate->es_into_oids;
2101         epqstate->es_topPlan = estate->es_topPlan;
2102
2103         /*
2104          * Each epqstate must have its own es_evTupleNull state, but all the
2105          * stack entries share es_evTuple state.  This allows sub-rechecks to
2106          * inherit the value being examined by an outer recheck.
2107          */
2108         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2109         if (priorepq == NULL)
2110                 /* first PQ stack entry */
2111                 epqstate->es_evTuple = (HeapTuple *)
2112                         palloc0(rtsize * sizeof(HeapTuple));
2113         else
2114                 /* later stack entries share the same storage */
2115                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2116
2117         epqstate->es_tupleTable =
2118                 ExecCreateTupleTable(estate->es_tupleTable->size);
2119
2120         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2121
2122         MemoryContextSwitchTo(oldcontext);
2123 }
2124
2125 /*
2126  * End execution of one level of PlanQual.
2127  *
2128  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2129  * of the normal cleanup, but *not* close result relations (which we are
2130  * just sharing from the outer query).
2131  */
2132 static void
2133 EvalPlanQualStop(evalPlanQual *epq)
2134 {
2135         EState     *epqstate = epq->estate;
2136         MemoryContext oldcontext;
2137
2138         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2139
2140         ExecEndNode(epq->planstate);
2141
2142         ExecDropTupleTable(epqstate->es_tupleTable, true);
2143         epqstate->es_tupleTable = NULL;
2144
2145         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2146         {
2147                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2148                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2149         }
2150
2151         MemoryContextSwitchTo(oldcontext);
2152
2153         FreeExecutorState(epqstate);
2154
2155         epq->estate = NULL;
2156         epq->planstate = NULL;
2157 }