granicus.if.org Git - postgresql/blob - src/backend/executor/execMain.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * execMain.c
   4  *        top level executor interface routines
   5  *
   6  * INTERFACE ROUTINES
   7  *      ExecutorStart()
   8  *      ExecutorRun()
   9  *      ExecutorEnd()
  10  *
  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),
  12  *      ExecutorRun() and ExecutorEnd()
  13  *
  14  *      These three procedures are the external interfaces to the executor.
  15  *      In each case, the query descriptor is required as an argument.
  16  *
  17  *      ExecutorStart() must be called at the beginning of execution of any
  18  *      query plan and ExecutorEnd() should always be called at the end of
  19  *      execution of a plan.
  20  *
  21  *      ExecutorRun accepts direction and count arguments that specify whether
  22  *      the plan is to be executed forwards, backwards, and for how many tuples.
  23  *
  24  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  25  * Portions Copyright (c) 1994, Regents of the University of California
  26  *
  27  *
  28  * IDENTIFICATION
  29  *        $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.232 2004/05/26 04:41:14 neilc Exp $
  30  *
  31  *-------------------------------------------------------------------------
  32  */
  33 #include "postgres.h"
  34
  35 #include "access/heapam.h"
  36 #include "catalog/heap.h"
  37 #include "catalog/namespace.h"
  38 #include "commands/tablecmds.h"
  39 #include "commands/trigger.h"
  40 #include "executor/execdebug.h"
  41 #include "executor/execdefs.h"
  42 #include "miscadmin.h"
  43 #include "optimizer/clauses.h"
  44 #include "optimizer/var.h"
  45 #include "parser/parsetree.h"
  46 #include "utils/acl.h"
  47 #include "utils/guc.h"
  48 #include "utils/lsyscache.h"
  49
  50
  51 typedef struct execRowMark
  52 {
  53         Relation        relation;
  54         Index           rti;
  55         char            resname[32];
  56 } execRowMark;
  57
  58 typedef struct evalPlanQual
  59 {
  60         Index           rti;
  61         EState     *estate;
  62         PlanState  *planstate;
  63         struct evalPlanQual *next;      /* stack of active PlanQual plans */
  64         struct evalPlanQual *free;      /* list of free PlanQual plans */
  65 } evalPlanQual;
  66
  67 /* decls for local routines only used within this module */
  68 static void InitPlan(QueryDesc *queryDesc, bool explainOnly);
  69 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  70                                   Index resultRelationIndex,
  71                                   List *rangeTable,
  72                                   CmdType operation);
  73 static TupleTableSlot *ExecutePlan(EState *estate, PlanState *planstate,
  74                         CmdType operation,
  75                         long numberTuples,
  76                         ScanDirection direction,
  77                         DestReceiver *dest);
  78 static void ExecSelect(TupleTableSlot *slot,
  79                    DestReceiver *dest,
  80                    EState *estate);
  81 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
  82                    EState *estate);
  83 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  84                    EState *estate);
  85 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
  86                    EState *estate);
  87 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  88 static void EndEvalPlanQual(EState *estate);
  89 static void ExecCheckRTEPerms(RangeTblEntry *rte);
  90 static void ExecCheckXactReadOnly(Query *parsetree);
  91 static void EvalPlanQualStart(evalPlanQual *epq, EState *estate,
  92                                   evalPlanQual *priorepq);
  93 static void EvalPlanQualStop(evalPlanQual *epq);
  94
  95 /* end of local decls */
  96
  97
  98 /* ----------------------------------------------------------------
  99  *              ExecutorStart
 100  *
 101  *              This routine must be called at the beginning of any execution of any
 102  *              query plan
 103  *
 104  * Takes a QueryDesc previously created by CreateQueryDesc (it's not real
 105  * clear why we bother to separate the two functions, but...).  The tupDesc
 106  * field of the QueryDesc is filled in to describe the tuples that will be
 107  * returned, and the internal fields (estate and planstate) are set up.
 108  *
 109  * If useCurrentSnapshot is true, run the query with the latest available
 110  * snapshot, instead of the normal QuerySnapshot.  Also, if it's an update
 111  * or delete query, check that the rows to be updated or deleted would be
 112  * visible to the normal QuerySnapshot.  (This is a special-case behavior
 113  * needed for referential integrity updates in serializable transactions.
 114  * We must check all currently-committed rows, but we want to throw a
 115  * can't-serialize error if any rows that would need updates would not be
 116  * visible under the normal serializable snapshot.)
 117  *
 118  * If explainOnly is true, we are not actually intending to run the plan,
 119  * only to set up for EXPLAIN; so skip unwanted side-effects.
 120  *
 121  * NB: the CurrentMemoryContext when this is called will become the parent
 122  * of the per-query context used for this Executor invocation.
 123  * ----------------------------------------------------------------
 124  */
 125 void
 126 ExecutorStart(QueryDesc *queryDesc, bool useCurrentSnapshot, bool explainOnly)
 127 {
 128         EState     *estate;
 129         MemoryContext oldcontext;
 130
 131         /* sanity checks: queryDesc must not be started already */
 132         Assert(queryDesc != NULL);
 133         Assert(queryDesc->estate == NULL);
 134
 135         /*
 136          * If the transaction is read-only, we need to check if any writes are
 137          * planned to non-temporary tables.
 138          */
 139         if (XactReadOnly && !explainOnly)
 140                 ExecCheckXactReadOnly(queryDesc->parsetree);
 141
 142         /*
 143          * Build EState, switch into per-query memory context for startup.
 144          */
 145         estate = CreateExecutorState();
 146         queryDesc->estate = estate;
 147
 148         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 149
 150         /*
 151          * Fill in parameters, if any, from queryDesc
 152          */
 153         estate->es_param_list_info = queryDesc->params;
 154
 155         if (queryDesc->plantree->nParamExec > 0)
 156                 estate->es_param_exec_vals = (ParamExecData *)
 157                         palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 158
 159         estate->es_instrument = queryDesc->doInstrument;
 160
 161         /*
 162          * Make our own private copy of the current query snapshot data.
 163          *
 164          * This "freezes" our idea of which tuples are good and which are not for
 165          * the life of this query, even if it outlives the current command and
 166          * current snapshot.
 167          */
 168         if (useCurrentSnapshot)
 169         {
 170                 /* RI update/delete query --- must use an up-to-date snapshot */
 171                 estate->es_snapshot = CopyCurrentSnapshot();
 172                 /* crosscheck updates/deletes against transaction snapshot */
 173                 estate->es_crosscheck_snapshot = CopyQuerySnapshot();
 174         }
 175         else
 176         {
 177                 /* normal query --- use query snapshot, no crosscheck */
 178                 estate->es_snapshot = CopyQuerySnapshot();
 179                 estate->es_crosscheck_snapshot = SnapshotAny;
 180         }
 181
 182         /*
 183          * Initialize the plan state tree
 184          */
 185         InitPlan(queryDesc, explainOnly);
 186
 187         MemoryContextSwitchTo(oldcontext);
 188 }
 189
 190 /* ----------------------------------------------------------------
 191  *              ExecutorRun
 192  *
 193  *              This is the main routine of the executor module. It accepts
 194  *              the query descriptor from the traffic cop and executes the
 195  *              query plan.
 196  *
 197  *              ExecutorStart must have been called already.
 198  *
 199  *              If direction is NoMovementScanDirection then nothing is done
 200  *              except to start up/shut down the destination.  Otherwise,
 201  *              we retrieve up to 'count' tuples in the specified direction.
 202  *
 203  *              Note: count = 0 is interpreted as no portal limit, i.e., run to
 204  *              completion.
 205  *
 206  * ----------------------------------------------------------------
 207  */
 208 TupleTableSlot *
 209 ExecutorRun(QueryDesc *queryDesc,
 210                         ScanDirection direction, long count)
 211 {
 212         EState     *estate;
 213         CmdType         operation;
 214         DestReceiver *dest;
 215         TupleTableSlot *result;
 216         MemoryContext oldcontext;
 217
 218         /* sanity checks */
 219         Assert(queryDesc != NULL);
 220
 221         estate = queryDesc->estate;
 222
 223         Assert(estate != NULL);
 224
 225         /*
 226          * Switch into per-query memory context
 227          */
 228         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 229
 230         /*
 231          * extract information from the query descriptor and the query
 232          * feature.
 233          */
 234         operation = queryDesc->operation;
 235         dest = queryDesc->dest;
 236
 237         /*
 238          * startup tuple receiver
 239          */
 240         estate->es_processed = 0;
 241         estate->es_lastoid = InvalidOid;
 242
 243         (*dest->rStartup) (dest, operation, queryDesc->tupDesc);
 244
 245         /*
 246          * run plan
 247          */
 248         if (direction == NoMovementScanDirection)
 249                 result = NULL;
 250         else
 251                 result = ExecutePlan(estate,
 252                                                          queryDesc->planstate,
 253                                                          operation,
 254                                                          count,
 255                                                          direction,
 256                                                          dest);
 257
 258         /*
 259          * shutdown receiver
 260          */
 261         (*dest->rShutdown) (dest);
 262
 263         MemoryContextSwitchTo(oldcontext);
 264
 265         return result;
 266 }
 267
 268 /* ----------------------------------------------------------------
 269  *              ExecutorEnd
 270  *
 271  *              This routine must be called at the end of execution of any
 272  *              query plan
 273  * ----------------------------------------------------------------
 274  */
 275 void
 276 ExecutorEnd(QueryDesc *queryDesc)
 277 {
 278         EState     *estate;
 279         MemoryContext oldcontext;
 280
 281         /* sanity checks */
 282         Assert(queryDesc != NULL);
 283
 284         estate = queryDesc->estate;
 285
 286         Assert(estate != NULL);
 287
 288         /*
 289          * Switch into per-query memory context to run ExecEndPlan
 290          */
 291         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 292
 293         ExecEndPlan(queryDesc->planstate, estate);
 294
 295         /*
 296          * Must switch out of context before destroying it
 297          */
 298         MemoryContextSwitchTo(oldcontext);
 299
 300         /*
 301          * Release EState and per-query memory context.  This should release
 302          * everything the executor has allocated.
 303          */
 304         FreeExecutorState(estate);
 305
 306         /* Reset queryDesc fields that no longer point to anything */
 307         queryDesc->tupDesc = NULL;
 308         queryDesc->estate = NULL;
 309         queryDesc->planstate = NULL;
 310 }
 311
 312 /* ----------------------------------------------------------------
 313  *              ExecutorRewind
 314  *
 315  *              This routine may be called on an open queryDesc to rewind it
 316  *              to the start.
 317  * ----------------------------------------------------------------
 318  */
 319 void
 320 ExecutorRewind(QueryDesc *queryDesc)
 321 {
 322         EState     *estate;
 323         MemoryContext oldcontext;
 324
 325         /* sanity checks */
 326         Assert(queryDesc != NULL);
 327
 328         estate = queryDesc->estate;
 329
 330         Assert(estate != NULL);
 331
 332         /* It's probably not sensible to rescan updating queries */
 333         Assert(queryDesc->operation == CMD_SELECT);
 334
 335         /*
 336          * Switch into per-query memory context
 337          */
 338         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 339
 340         /*
 341          * rescan plan
 342          */
 343         ExecReScan(queryDesc->planstate, NULL);
 344
 345         MemoryContextSwitchTo(oldcontext);
 346 }
 347
 348
 349 /*
 350  * ExecCheckRTPerms
 351  *              Check access permissions for all relations listed in a range table.
 352  */
 353 void
 354 ExecCheckRTPerms(List *rangeTable)
 355 {
 356         ListCell   *l;
 357
 358         foreach(l, rangeTable)
 359         {
 360                 RangeTblEntry *rte = lfirst(l);
 361
 362                 ExecCheckRTEPerms(rte);
 363         }
 364 }
 365
 366 /*
 367  * ExecCheckRTEPerms
 368  *              Check access permissions for a single RTE.
 369  */
 370 static void
 371 ExecCheckRTEPerms(RangeTblEntry *rte)
 372 {
 373         AclMode         requiredPerms;
 374         Oid                     relOid;
 375         AclId           userid;
 376
 377         /*
 378          * If it's a subquery, recursively examine its rangetable.
 379          */
 380         if (rte->rtekind == RTE_SUBQUERY)
 381         {
 382                 ExecCheckRTPerms(rte->subquery->rtable);
 383                 return;
 384         }
 385
 386         /*
 387          * Otherwise, only plain-relation RTEs need to be checked here.
 388          * Function RTEs are checked by init_fcache when the function is
 389          * prepared for execution. Join and special RTEs need no checks.
 390          */
 391         if (rte->rtekind != RTE_RELATION)
 392                 return;
 393
 394         /*
 395          * No work if requiredPerms is empty.
 396          */
 397         requiredPerms = rte->requiredPerms;
 398         if (requiredPerms == 0)
 399                 return;
 400
 401         relOid = rte->relid;
 402
 403         /*
 404          * userid to check as: current user unless we have a setuid
 405          * indication.
 406          *
 407          * Note: GetUserId() is presently fast enough that there's no harm in
 408          * calling it separately for each RTE.  If that stops being true, we
 409          * could call it once in ExecCheckRTPerms and pass the userid down
 410          * from there.  But for now, no need for the extra clutter.
 411          */
 412         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 413
 414         /*
 415          * We must have *all* the requiredPerms bits, so use aclmask not
 416          * aclcheck.
 417          */
 418         if (pg_class_aclmask(relOid, userid, requiredPerms, ACLMASK_ALL)
 419                 != requiredPerms)
 420                 aclcheck_error(ACLCHECK_NO_PRIV, ACL_KIND_CLASS,
 421                                            get_rel_name(relOid));
 422 }
 423
 424 /*
 425  * Check that the query does not imply any writes to non-temp tables.
 426  */
 427 static void
 428 ExecCheckXactReadOnly(Query *parsetree)
 429 {
 430         ListCell   *l;
 431
 432         /*
 433          * CREATE TABLE AS or SELECT INTO?
 434          *
 435          * XXX should we allow this if the destination is temp?
 436          */
 437         if (parsetree->into != NULL)
 438                 goto fail;
 439
 440         /* Fail if write permissions are requested on any non-temp table */
 441         foreach(l, parsetree->rtable)
 442         {
 443                 RangeTblEntry *rte = lfirst(l);
 444
 445                 if (rte->rtekind == RTE_SUBQUERY)
 446                 {
 447                         ExecCheckXactReadOnly(rte->subquery);
 448                         continue;
 449                 }
 450
 451                 if (rte->rtekind != RTE_RELATION)
 452                         continue;
 453
 454                 if ((rte->requiredPerms & (~ACL_SELECT)) == 0)
 455                         continue;
 456
 457                 if (isTempNamespace(get_rel_namespace(rte->relid)))
 458                         continue;
 459
 460                 goto fail;
 461         }
 462
 463         return;
 464
 465 fail:
 466         ereport(ERROR,
 467                         (errcode(ERRCODE_READ_ONLY_SQL_TRANSACTION),
 468                          errmsg("transaction is read-only")));
 469 }
 470
 471
 472 /* ----------------------------------------------------------------
 473  *              InitPlan
 474  *
 475  *              Initializes the query plan: open files, allocate storage
 476  *              and start up the rule manager
 477  * ----------------------------------------------------------------
 478  */
 479 static void
 480 InitPlan(QueryDesc *queryDesc, bool explainOnly)
 481 {
 482         CmdType         operation = queryDesc->operation;
 483         Query      *parseTree = queryDesc->parsetree;
 484         Plan       *plan = queryDesc->plantree;
 485         EState     *estate = queryDesc->estate;
 486         PlanState  *planstate;
 487         List       *rangeTable;
 488         Relation        intoRelationDesc;
 489         bool            do_select_into;
 490         TupleDesc       tupType;
 491
 492         /*
 493          * Do permissions checks.  It's sufficient to examine the query's top
 494          * rangetable here --- subplan RTEs will be checked during
 495          * ExecInitSubPlan().
 496          */
 497         ExecCheckRTPerms(parseTree->rtable);
 498
 499         /*
 500          * get information from query descriptor
 501          */
 502         rangeTable = parseTree->rtable;
 503
 504         /*
 505          * initialize the node's execution state
 506          */
 507         estate->es_range_table = rangeTable;
 508
 509         /*
 510          * if there is a result relation, initialize result relation stuff
 511          */
 512         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 513         {
 514                 List       *resultRelations = parseTree->resultRelations;
 515                 int                     numResultRelations;
 516                 ResultRelInfo *resultRelInfos;
 517
 518                 if (resultRelations != NIL)
 519                 {
 520                         /*
 521                          * Multiple result relations (due to inheritance)
 522                          * parseTree->resultRelations identifies them all
 523                          */
 524                         ResultRelInfo   *resultRelInfo;
 525                         ListCell                *l;
 526
 527                         numResultRelations = length(resultRelations);
 528                         resultRelInfos = (ResultRelInfo *)
 529                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 530                         resultRelInfo = resultRelInfos;
 531                         foreach(l, resultRelations)
 532                         {
 533                                 initResultRelInfo(resultRelInfo,
 534                                                                   lfirst_int(l),
 535                                                                   rangeTable,
 536                                                                   operation);
 537                                 resultRelInfo++;
 538                         }
 539                 }
 540                 else
 541                 {
 542                         /*
 543                          * Single result relation identified by
 544                          * parseTree->resultRelation
 545                          */
 546                         numResultRelations = 1;
 547                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 548                         initResultRelInfo(resultRelInfos,
 549                                                           parseTree->resultRelation,
 550                                                           rangeTable,
 551                                                           operation);
 552                 }
 553
 554                 estate->es_result_relations = resultRelInfos;
 555                 estate->es_num_result_relations = numResultRelations;
 556                 /* Initialize to first or only result rel */
 557                 estate->es_result_relation_info = resultRelInfos;
 558         }
 559         else
 560         {
 561                 /*
 562                  * if no result relation, then set state appropriately
 563                  */
 564                 estate->es_result_relations = NULL;
 565                 estate->es_num_result_relations = 0;
 566                 estate->es_result_relation_info = NULL;
 567         }
 568
 569         /*
 570          * Detect whether we're doing SELECT INTO.  If so, set the force_oids
 571          * flag appropriately so that the plan tree will be initialized with
 572          * the correct tuple descriptors.
 573          */
 574         do_select_into = false;
 575
 576         if (operation == CMD_SELECT && parseTree->into != NULL)
 577         {
 578                 do_select_into = true;
 579                 estate->es_select_into = true;
 580                 estate->es_into_oids = parseTree->intoHasOids;
 581         }
 582
 583         /*
 584          * Have to lock relations selected for update
 585          */
 586         estate->es_rowMark = NIL;
 587         if (parseTree->rowMarks != NIL)
 588         {
 589                 ListCell   *l;
 590
 591                 foreach(l, parseTree->rowMarks)
 592                 {
 593                         Index           rti = lfirsti(l);
 594                         Oid                     relid = getrelid(rti, rangeTable);
 595                         Relation        relation;
 596                         execRowMark *erm;
 597
 598                         relation = heap_open(relid, RowShareLock);
 599                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 600                         erm->relation = relation;
 601                         erm->rti = rti;
 602                         snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
 603                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 604                 }
 605         }
 606
 607         /*
 608          * initialize the executor "tuple" table.  We need slots for all the
 609          * plan nodes, plus possibly output slots for the junkfilter(s). At
 610          * this point we aren't sure if we need junkfilters, so just add slots
 611          * for them unconditionally.
 612          */
 613         {
 614                 int                     nSlots = ExecCountSlotsNode(plan);
 615
 616                 if (parseTree->resultRelations != NIL)
 617                         nSlots += length(parseTree->resultRelations);
 618                 else
 619                         nSlots += 1;
 620                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 621         }
 622
 623         /* mark EvalPlanQual not active */
 624         estate->es_topPlan = plan;
 625         estate->es_evalPlanQual = NULL;
 626         estate->es_evTupleNull = NULL;
 627         estate->es_evTuple = NULL;
 628         estate->es_useEvalPlan = false;
 629
 630         /*
 631          * initialize the private state information for all the nodes in the
 632          * query tree.  This opens files, allocates storage and leaves us
 633          * ready to start processing tuples.
 634          */
 635         planstate = ExecInitNode(plan, estate);
 636
 637         /*
 638          * Get the tuple descriptor describing the type of tuples to return.
 639          * (this is especially important if we are creating a relation with
 640          * "SELECT INTO")
 641          */
 642         tupType = ExecGetResultType(planstate);
 643
 644         /*
 645          * Initialize the junk filter if needed.  SELECT and INSERT queries
 646          * need a filter if there are any junk attrs in the tlist.      INSERT and
 647          * SELECT INTO also need a filter if the plan may return raw disk tuples
 648          * (else heap_insert will be scribbling on the source relation!).
 649          * UPDATE and DELETE always need a filter, since there's always a junk
 650          * 'ctid' attribute present --- no need to look first.
 651          */
 652         {
 653                 bool            junk_filter_needed = false;
 654                 ListCell   *tlist;
 655
 656                 switch (operation)
 657                 {
 658                         case CMD_SELECT:
 659                         case CMD_INSERT:
 660                                 foreach(tlist, plan->targetlist)
 661                                 {
 662                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 663
 664                                         if (tle->resdom->resjunk)
 665                                         {
 666                                                 junk_filter_needed = true;
 667                                                 break;
 668                                         }
 669                                 }
 670                                 if (!junk_filter_needed &&
 671                                         (operation == CMD_INSERT || do_select_into) &&
 672                                         ExecMayReturnRawTuples(planstate))
 673                                         junk_filter_needed = true;
 674                                 break;
 675                         case CMD_UPDATE:
 676                         case CMD_DELETE:
 677                                 junk_filter_needed = true;
 678                                 break;
 679                         default:
 680                                 break;
 681                 }
 682
 683                 if (junk_filter_needed)
 684                 {
 685                         /*
 686                          * If there are multiple result relations, each one needs its
 687                          * own junk filter.  Note this is only possible for
 688                          * UPDATE/DELETE, so we can't be fooled by some needing a
 689                          * filter and some not.
 690                          */
 691                         if (parseTree->resultRelations != NIL)
 692                         {
 693                                 PlanState **appendplans;
 694                                 int                     as_nplans;
 695                                 ResultRelInfo *resultRelInfo;
 696                                 int                     i;
 697
 698                                 /* Top plan had better be an Append here. */
 699                                 Assert(IsA(plan, Append));
 700                                 Assert(((Append *) plan)->isTarget);
 701                                 Assert(IsA(planstate, AppendState));
 702                                 appendplans = ((AppendState *) planstate)->appendplans;
 703                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 704                                 Assert(as_nplans == estate->es_num_result_relations);
 705                                 resultRelInfo = estate->es_result_relations;
 706                                 for (i = 0; i < as_nplans; i++)
 707                                 {
 708                                         PlanState  *subplan = appendplans[i];
 709                                         JunkFilter *j;
 710
 711                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 712                                                                                    ExecGetResultType(subplan),
 713                                                           ExecAllocTableSlot(estate->es_tupleTable));
 714                                         resultRelInfo->ri_junkFilter = j;
 715                                         resultRelInfo++;
 716                                 }
 717
 718                                 /*
 719                                  * Set active junkfilter too; at this point ExecInitAppend
 720                                  * has already selected an active result relation...
 721                                  */
 722                                 estate->es_junkFilter =
 723                                         estate->es_result_relation_info->ri_junkFilter;
 724                         }
 725                         else
 726                         {
 727                                 /* Normal case with just one JunkFilter */
 728                                 JunkFilter *j;
 729
 730                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 731                                                                            tupType,
 732                                                           ExecAllocTableSlot(estate->es_tupleTable));
 733                                 estate->es_junkFilter = j;
 734                                 if (estate->es_result_relation_info)
 735                                         estate->es_result_relation_info->ri_junkFilter = j;
 736
 737                                 /* For SELECT, want to return the cleaned tuple type */
 738                                 if (operation == CMD_SELECT)
 739                                         tupType = j->jf_cleanTupType;
 740                         }
 741                 }
 742                 else
 743                         estate->es_junkFilter = NULL;
 744         }
 745
 746         /*
 747          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 748          * till now so we have the "clean" result tuple type to create the new
 749          * table from.
 750          *
 751          * If EXPLAIN, skip creating the "into" relation.
 752          */
 753         intoRelationDesc = NULL;
 754
 755         if (do_select_into && !explainOnly)
 756         {
 757                 char       *intoName;
 758                 Oid                     namespaceId;
 759                 AclResult       aclresult;
 760                 Oid                     intoRelationId;
 761                 TupleDesc       tupdesc;
 762
 763                 /*
 764                  * find namespace to create in, check permissions
 765                  */
 766                 intoName = parseTree->into->relname;
 767                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 768
 769                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 770                                                                                   ACL_CREATE);
 771                 if (aclresult != ACLCHECK_OK)
 772                         aclcheck_error(aclresult, ACL_KIND_NAMESPACE,
 773                                                    get_namespace_name(namespaceId));
 774
 775                 /*
 776                  * have to copy tupType to get rid of constraints
 777                  */
 778                 tupdesc = CreateTupleDescCopy(tupType);
 779
 780                 intoRelationId = heap_create_with_catalog(intoName,
 781                                                                                                   namespaceId,
 782                                                                                                   tupdesc,
 783                                                                                                   RELKIND_RELATION,
 784                                                                                                   false,
 785                                                                                                   true,
 786                                                                                                   0,
 787                                                                                                   ONCOMMIT_NOOP,
 788                                                                                                   allowSystemTableMods);
 789
 790                 FreeTupleDesc(tupdesc);
 791
 792                 /*
 793                  * Advance command counter so that the newly-created relation's
 794                  * catalog tuples will be visible to heap_open.
 795                  */
 796                 CommandCounterIncrement();
 797
 798                 /*
 799                  * If necessary, create a TOAST table for the into relation. Note
 800                  * that AlterTableCreateToastTable ends with
 801                  * CommandCounterIncrement(), so that the TOAST table will be
 802                  * visible for insertion.
 803                  */
 804                 AlterTableCreateToastTable(intoRelationId, true);
 805
 806                 /*
 807                  * And open the constructed table for writing.
 808                  */
 809                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 810         }
 811
 812         estate->es_into_relation_descriptor = intoRelationDesc;
 813
 814         queryDesc->tupDesc = tupType;
 815         queryDesc->planstate = planstate;
 816 }
 817
 818 /*
 819  * Initialize ResultRelInfo data for one result relation
 820  */
 821 static void
 822 initResultRelInfo(ResultRelInfo *resultRelInfo,
 823                                   Index resultRelationIndex,
 824                                   List *rangeTable,
 825                                   CmdType operation)
 826 {
 827         Oid                     resultRelationOid;
 828         Relation        resultRelationDesc;
 829
 830         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 831         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 832
 833         switch (resultRelationDesc->rd_rel->relkind)
 834         {
 835                 case RELKIND_SEQUENCE:
 836                         ereport(ERROR,
 837                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 838                                          errmsg("cannot change sequence \"%s\"",
 839                                                   RelationGetRelationName(resultRelationDesc))));
 840                         break;
 841                 case RELKIND_TOASTVALUE:
 842                         ereport(ERROR,
 843                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 844                                          errmsg("cannot change TOAST relation \"%s\"",
 845                                                   RelationGetRelationName(resultRelationDesc))));
 846                         break;
 847                 case RELKIND_VIEW:
 848                         ereport(ERROR,
 849                                         (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 850                                          errmsg("cannot change view \"%s\"",
 851                                                   RelationGetRelationName(resultRelationDesc))));
 852                         break;
 853         }
 854
 855         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 856         resultRelInfo->type = T_ResultRelInfo;
 857         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 858         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 859         resultRelInfo->ri_NumIndices = 0;
 860         resultRelInfo->ri_IndexRelationDescs = NULL;
 861         resultRelInfo->ri_IndexRelationInfo = NULL;
 862         /* make a copy so as not to depend on relcache info not changing... */
 863         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 864         resultRelInfo->ri_TrigFunctions = NULL;
 865         resultRelInfo->ri_ConstraintExprs = NULL;
 866         resultRelInfo->ri_junkFilter = NULL;
 867
 868         /*
 869          * If there are indices on the result relation, open them and save
 870          * descriptors in the result relation info, so that we can add new
 871          * index entries for the tuples we add/update.  We need not do this
 872          * for a DELETE, however, since deletion doesn't affect indexes.
 873          */
 874         if (resultRelationDesc->rd_rel->relhasindex &&
 875                 operation != CMD_DELETE)
 876                 ExecOpenIndices(resultRelInfo);
 877 }
 878
 879 /*
 880  *              ExecContextForcesOids
 881  *
 882  * This is pretty grotty: when doing INSERT, UPDATE, or SELECT INTO,
 883  * we need to ensure that result tuples have space for an OID iff they are
 884  * going to be stored into a relation that has OIDs.  In other contexts
 885  * we are free to choose whether to leave space for OIDs in result tuples
 886  * (we generally don't want to, but we do if a physical-tlist optimization
 887  * is possible).  This routine checks the plan context and returns TRUE if the
 888  * choice is forced, FALSE if the choice is not forced.  In the TRUE case,
 889  * *hasoids is set to the required value.
 890  *
 891  * One reason this is ugly is that all plan nodes in the plan tree will emit
 892  * tuples with space for an OID, though we really only need the topmost node
 893  * to do so.  However, node types like Sort don't project new tuples but just
 894  * return their inputs, and in those cases the requirement propagates down
 895  * to the input node.  Eventually we might make this code smart enough to
 896  * recognize how far down the requirement really goes, but for now we just
 897  * make all plan nodes do the same thing if the top level forces the choice.
 898  *
 899  * We assume that estate->es_result_relation_info is already set up to
 900  * describe the target relation.  Note that in an UPDATE that spans an
 901  * inheritance tree, some of the target relations may have OIDs and some not.
 902  * We have to make the decisions on a per-relation basis as we initialize
 903  * each of the child plans of the topmost Append plan.
 904  *
 905  * SELECT INTO is even uglier, because we don't have the INTO relation's
 906  * descriptor available when this code runs; we have to look aside at a
 907  * flag set by InitPlan().
 908  */
 909 bool
 910 ExecContextForcesOids(PlanState *planstate, bool *hasoids)
 911 {
 912         if (planstate->state->es_select_into)
 913         {
 914                 *hasoids = planstate->state->es_into_oids;
 915                 return true;
 916         }
 917         else
 918         {
 919                 ResultRelInfo *ri = planstate->state->es_result_relation_info;
 920
 921                 if (ri != NULL)
 922                 {
 923                         Relation        rel = ri->ri_RelationDesc;
 924
 925                         if (rel != NULL)
 926                         {
 927                                 *hasoids = rel->rd_rel->relhasoids;
 928                                 return true;
 929                         }
 930                 }
 931         }
 932
 933         return false;
 934 }
 935
 936 /* ----------------------------------------------------------------
 937  *              ExecEndPlan
 938  *
 939  *              Cleans up the query plan -- closes files and frees up storage
 940  *
 941  * NOTE: we are no longer very worried about freeing storage per se
 942  * in this code; FreeExecutorState should be guaranteed to release all
 943  * memory that needs to be released.  What we are worried about doing
 944  * is closing relations and dropping buffer pins.  Thus, for example,
 945  * tuple tables must be cleared or dropped to ensure pins are released.
 946  * ----------------------------------------------------------------
 947  */
 948 void
 949 ExecEndPlan(PlanState *planstate, EState *estate)
 950 {
 951         ResultRelInfo *resultRelInfo;
 952         int                     i;
 953         ListCell   *l;
 954
 955         /*
 956          * shut down any PlanQual processing we were doing
 957          */
 958         if (estate->es_evalPlanQual != NULL)
 959                 EndEvalPlanQual(estate);
 960
 961         /*
 962          * shut down the node-type-specific query processing
 963          */
 964         ExecEndNode(planstate);
 965
 966         /*
 967          * destroy the executor "tuple" table.
 968          */
 969         ExecDropTupleTable(estate->es_tupleTable, true);
 970         estate->es_tupleTable = NULL;
 971
 972         /*
 973          * close the result relation(s) if any, but hold locks until xact
 974          * commit.
 975          */
 976         resultRelInfo = estate->es_result_relations;
 977         for (i = estate->es_num_result_relations; i > 0; i--)
 978         {
 979                 /* Close indices and then the relation itself */
 980                 ExecCloseIndices(resultRelInfo);
 981                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 982                 resultRelInfo++;
 983         }
 984
 985         /*
 986          * close the "into" relation if necessary, again keeping lock
 987          */
 988         if (estate->es_into_relation_descriptor != NULL)
 989                 heap_close(estate->es_into_relation_descriptor, NoLock);
 990
 991         /*
 992          * close any relations selected FOR UPDATE, again keeping locks
 993          */
 994         foreach(l, estate->es_rowMark)
 995         {
 996                 execRowMark *erm = lfirst(l);
 997
 998                 heap_close(erm->relation, NoLock);
 999         }
1000 }
1001
1002 /* ----------------------------------------------------------------
1003  *              ExecutePlan
1004  *
1005  *              processes the query plan to retrieve 'numberTuples' tuples in the
1006  *              direction specified.
1007  *
1008  *              Retrieves all tuples if numberTuples is 0
1009  *
1010  *              result is either a slot containing the last tuple in the case
1011  *              of a SELECT or NULL otherwise.
1012  *
1013  * Note: the ctid attribute is a 'junk' attribute that is removed before the
1014  * user can see it
1015  * ----------------------------------------------------------------
1016  */
1017 static TupleTableSlot *
1018 ExecutePlan(EState *estate,
1019                         PlanState *planstate,
1020                         CmdType operation,
1021                         long numberTuples,
1022                         ScanDirection direction,
1023                         DestReceiver *dest)
1024 {
1025         JunkFilter *junkfilter;
1026         TupleTableSlot *slot;
1027         ItemPointer tupleid = NULL;
1028         ItemPointerData tuple_ctid;
1029         long            current_tuple_count;
1030         TupleTableSlot *result;
1031
1032         /*
1033          * initialize local variables
1034          */
1035         slot = NULL;
1036         current_tuple_count = 0;
1037         result = NULL;
1038
1039         /*
1040          * Set the direction.
1041          */
1042         estate->es_direction = direction;
1043
1044         /*
1045          * Process BEFORE EACH STATEMENT triggers
1046          */
1047         switch (operation)
1048         {
1049                 case CMD_UPDATE:
1050                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
1051                         break;
1052                 case CMD_DELETE:
1053                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
1054                         break;
1055                 case CMD_INSERT:
1056                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
1057                         break;
1058                 default:
1059                         /* do nothing */
1060                         break;
1061         }
1062
1063         /*
1064          * Loop until we've processed the proper number of tuples from the
1065          * plan.
1066          */
1067
1068         for (;;)
1069         {
1070                 /* Reset the per-output-tuple exprcontext */
1071                 ResetPerTupleExprContext(estate);
1072
1073                 /*
1074                  * Execute the plan and obtain a tuple
1075                  */
1076 lnext:  ;
1077                 if (estate->es_useEvalPlan)
1078                 {
1079                         slot = EvalPlanQualNext(estate);
1080                         if (TupIsNull(slot))
1081                                 slot = ExecProcNode(planstate);
1082                 }
1083                 else
1084                         slot = ExecProcNode(planstate);
1085
1086                 /*
1087                  * if the tuple is null, then we assume there is nothing more to
1088                  * process so we just return null...
1089                  */
1090                 if (TupIsNull(slot))
1091                 {
1092                         result = NULL;
1093                         break;
1094                 }
1095
1096                 /*
1097                  * if we have a junk filter, then project a new tuple with the
1098                  * junk removed.
1099                  *
1100                  * Store this new "clean" tuple in the junkfilter's resultSlot.
1101                  * (Formerly, we stored it back over the "dirty" tuple, which is
1102                  * WRONG because that tuple slot has the wrong descriptor.)
1103                  *
1104                  * Also, extract all the junk information we need.
1105                  */
1106                 if ((junkfilter = estate->es_junkFilter) != NULL)
1107                 {
1108                         Datum           datum;
1109                         HeapTuple       newTuple;
1110                         bool            isNull;
1111
1112                         /*
1113                          * extract the 'ctid' junk attribute.
1114                          */
1115                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1116                         {
1117                                 if (!ExecGetJunkAttribute(junkfilter,
1118                                                                                   slot,
1119                                                                                   "ctid",
1120                                                                                   &datum,
1121                                                                                   &isNull))
1122                                         elog(ERROR, "could not find junk ctid column");
1123
1124                                 /* shouldn't ever get a null result... */
1125                                 if (isNull)
1126                                         elog(ERROR, "ctid is NULL");
1127
1128                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1129                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1130                                                                                  * ctid!! */
1131                                 tupleid = &tuple_ctid;
1132                         }
1133                         else if (estate->es_rowMark != NIL)
1134                         {
1135                                 ListCell   *l;
1136
1137                 lmark:  ;
1138                                 foreach(l, estate->es_rowMark)
1139                                 {
1140                                         execRowMark *erm = lfirst(l);
1141                                         Buffer          buffer;
1142                                         HeapTupleData tuple;
1143                                         TupleTableSlot *newSlot;
1144                                         int                     test;
1145
1146                                         if (!ExecGetJunkAttribute(junkfilter,
1147                                                                                           slot,
1148                                                                                           erm->resname,
1149                                                                                           &datum,
1150                                                                                           &isNull))
1151                                                 elog(ERROR, "could not find junk \"%s\" column",
1152                                                          erm->resname);
1153
1154                                         /* shouldn't ever get a null result... */
1155                                         if (isNull)
1156                                                 elog(ERROR, "\"%s\" is NULL", erm->resname);
1157
1158                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1159                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1160                                                                                         estate->es_snapshot->curcid);
1161                                         ReleaseBuffer(buffer);
1162                                         switch (test)
1163                                         {
1164                                                 case HeapTupleSelfUpdated:
1165                                                         /* treat it as deleted; do not process */
1166                                                         goto lnext;
1167
1168                                                 case HeapTupleMayBeUpdated:
1169                                                         break;
1170
1171                                                 case HeapTupleUpdated:
1172                                                         if (IsXactIsoLevelSerializable)
1173                                                                 ereport(ERROR,
1174                                                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1175                                                                                  errmsg("could not serialize access due to concurrent update")));
1176                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1177                                                                   (ItemPointer) DatumGetPointer(datum))))
1178                                                         {
1179                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1180                                                                 if (!(TupIsNull(newSlot)))
1181                                                                 {
1182                                                                         slot = newSlot;
1183                                                                         estate->es_useEvalPlan = true;
1184                                                                         goto lmark;
1185                                                                 }
1186                                                         }
1187
1188                                                         /*
1189                                                          * if tuple was deleted or PlanQual failed for
1190                                                          * updated tuple - we must not return this
1191                                                          * tuple!
1192                                                          */
1193                                                         goto lnext;
1194
1195                                                 default:
1196                                                         elog(ERROR, "unrecognized heap_mark4update status: %u",
1197                                                                  test);
1198                                                         return (NULL);
1199                                         }
1200                                 }
1201                         }
1202
1203                         /*
1204                          * Finally create a new "clean" tuple with all junk attributes
1205                          * removed
1206                          */
1207                         newTuple = ExecRemoveJunk(junkfilter, slot);
1208
1209                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1210                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1211                                                                   InvalidBuffer,                /* this tuple has no
1212                                                                                                                  * buffer */
1213                                                                   true);                /* tuple should be pfreed */
1214                 }
1215
1216                 /*
1217                  * now that we have a tuple, do the appropriate thing with it..
1218                  * either return it to the user, add it to a relation someplace,
1219                  * delete it from a relation, or modify some of its attributes.
1220                  */
1221                 switch (operation)
1222                 {
1223                         case CMD_SELECT:
1224                                 ExecSelect(slot,        /* slot containing tuple */
1225                                                    dest,        /* destination's tuple-receiver obj */
1226                                                    estate);
1227                                 result = slot;
1228                                 break;
1229
1230                         case CMD_INSERT:
1231                                 ExecInsert(slot, tupleid, estate);
1232                                 result = NULL;
1233                                 break;
1234
1235                         case CMD_DELETE:
1236                                 ExecDelete(slot, tupleid, estate);
1237                                 result = NULL;
1238                                 break;
1239
1240                         case CMD_UPDATE:
1241                                 ExecUpdate(slot, tupleid, estate);
1242                                 result = NULL;
1243                                 break;
1244
1245                         default:
1246                                 elog(ERROR, "unrecognized operation code: %d",
1247                                          (int) operation);
1248                                 result = NULL;
1249                                 break;
1250                 }
1251
1252                 /*
1253                  * check our tuple count.. if we've processed the proper number
1254                  * then quit, else loop again and process more tuples.  Zero
1255                  * numberTuples means no limit.
1256                  */
1257                 current_tuple_count++;
1258                 if (numberTuples && numberTuples == current_tuple_count)
1259                         break;
1260         }
1261
1262         /*
1263          * Process AFTER EACH STATEMENT triggers
1264          */
1265         switch (operation)
1266         {
1267                 case CMD_UPDATE:
1268                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1269                         break;
1270                 case CMD_DELETE:
1271                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1272                         break;
1273                 case CMD_INSERT:
1274                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1275                         break;
1276                 default:
1277                         /* do nothing */
1278                         break;
1279         }
1280
1281         /*
1282          * here, result is either a slot containing a tuple in the case of a
1283          * SELECT or NULL otherwise.
1284          */
1285         return result;
1286 }
1287
1288 /* ----------------------------------------------------------------
1289  *              ExecSelect
1290  *
1291  *              SELECTs are easy.. we just pass the tuple to the appropriate
1292  *              print function.  The only complexity is when we do a
1293  *              "SELECT INTO", in which case we insert the tuple into
1294  *              the appropriate relation (note: this is a newly created relation
1295  *              so we don't need to worry about indices or locks.)
1296  * ----------------------------------------------------------------
1297  */
1298 static void
1299 ExecSelect(TupleTableSlot *slot,
1300                    DestReceiver *dest,
1301                    EState *estate)
1302 {
1303         HeapTuple       tuple;
1304         TupleDesc       attrtype;
1305
1306         /*
1307          * get the heap tuple out of the tuple table slot
1308          */
1309         tuple = slot->val;
1310         attrtype = slot->ttc_tupleDescriptor;
1311
1312         /*
1313          * insert the tuple into the "into relation"
1314          *
1315          * XXX this probably ought to be replaced by a separate destination
1316          */
1317         if (estate->es_into_relation_descriptor != NULL)
1318         {
1319                 heap_insert(estate->es_into_relation_descriptor, tuple,
1320                                         estate->es_snapshot->curcid);
1321                 IncrAppended();
1322         }
1323
1324         /*
1325          * send the tuple to the destination
1326          */
1327         (*dest->receiveTuple) (tuple, attrtype, dest);
1328         IncrRetrieved();
1329         (estate->es_processed)++;
1330 }
1331
1332 /* ----------------------------------------------------------------
1333  *              ExecInsert
1334  *
1335  *              INSERTs are trickier.. we have to insert the tuple into
1336  *              the base relation and insert appropriate tuples into the
1337  *              index relations.
1338  * ----------------------------------------------------------------
1339  */
1340 static void
1341 ExecInsert(TupleTableSlot *slot,
1342                    ItemPointer tupleid,
1343                    EState *estate)
1344 {
1345         HeapTuple       tuple;
1346         ResultRelInfo *resultRelInfo;
1347         Relation        resultRelationDesc;
1348         int                     numIndices;
1349         Oid                     newId;
1350
1351         /*
1352          * get the heap tuple out of the tuple table slot
1353          */
1354         tuple = slot->val;
1355
1356         /*
1357          * get information on the (current) result relation
1358          */
1359         resultRelInfo = estate->es_result_relation_info;
1360         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1361
1362         /* BEFORE ROW INSERT Triggers */
1363         if (resultRelInfo->ri_TrigDesc &&
1364           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1365         {
1366                 HeapTuple       newtuple;
1367
1368                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1369
1370                 if (newtuple == NULL)   /* "do nothing" */
1371                         return;
1372
1373                 if (newtuple != tuple)  /* modified by Trigger(s) */
1374                 {
1375                         /*
1376                          * Insert modified tuple into tuple table slot, replacing the
1377                          * original.  We assume that it was allocated in per-tuple
1378                          * memory context, and therefore will go away by itself. The
1379                          * tuple table slot should not try to clear it.
1380                          */
1381                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1382                         tuple = newtuple;
1383                 }
1384         }
1385
1386         /*
1387          * Check the constraints of the tuple
1388          */
1389         if (resultRelationDesc->rd_att->constr)
1390                 ExecConstraints(resultRelInfo, slot, estate);
1391
1392         /*
1393          * insert the tuple
1394          */
1395         newId = heap_insert(resultRelationDesc, tuple,
1396                                                 estate->es_snapshot->curcid);
1397
1398         IncrAppended();
1399         (estate->es_processed)++;
1400         estate->es_lastoid = newId;
1401         setLastTid(&(tuple->t_self));
1402
1403         /*
1404          * process indices
1405          *
1406          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1407          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1408          * field.
1409          */
1410         numIndices = resultRelInfo->ri_NumIndices;
1411         if (numIndices > 0)
1412                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1413
1414         /* AFTER ROW INSERT Triggers */
1415         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1416 }
1417
1418 /* ----------------------------------------------------------------
1419  *              ExecDelete
1420  *
1421  *              DELETE is like UPDATE, we delete the tuple and its
1422  *              index tuples.
1423  * ----------------------------------------------------------------
1424  */
1425 static void
1426 ExecDelete(TupleTableSlot *slot,
1427                    ItemPointer tupleid,
1428                    EState *estate)
1429 {
1430         ResultRelInfo *resultRelInfo;
1431         Relation        resultRelationDesc;
1432         ItemPointerData ctid;
1433         int                     result;
1434
1435         /*
1436          * get information on the (current) result relation
1437          */
1438         resultRelInfo = estate->es_result_relation_info;
1439         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1440
1441         /* BEFORE ROW DELETE Triggers */
1442         if (resultRelInfo->ri_TrigDesc &&
1443           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1444         {
1445                 bool            dodelete;
1446
1447                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1448                                                                                 estate->es_snapshot->curcid);
1449
1450                 if (!dodelete)                  /* "do nothing" */
1451                         return;
1452         }
1453
1454         /*
1455          * delete the tuple
1456          */
1457 ldelete:;
1458         result = heap_delete(resultRelationDesc, tupleid,
1459                                                  &ctid,
1460                                                  estate->es_snapshot->curcid,
1461                                                  estate->es_crosscheck_snapshot,
1462                                                  true /* wait for commit */);
1463         switch (result)
1464         {
1465                 case HeapTupleSelfUpdated:
1466                         /* already deleted by self; nothing to do */
1467                         return;
1468
1469                 case HeapTupleMayBeUpdated:
1470                         break;
1471
1472                 case HeapTupleUpdated:
1473                         if (IsXactIsoLevelSerializable)
1474                                 ereport(ERROR,
1475                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1476                                                  errmsg("could not serialize access due to concurrent update")));
1477                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1478                         {
1479                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1480                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1481
1482                                 if (!TupIsNull(epqslot))
1483                                 {
1484                                         *tupleid = ctid;
1485                                         goto ldelete;
1486                                 }
1487                         }
1488                         /* tuple already deleted; nothing to do */
1489                         return;
1490
1491                 default:
1492                         elog(ERROR, "unrecognized heap_delete status: %u", result);
1493                         return;
1494         }
1495
1496         IncrDeleted();
1497         (estate->es_processed)++;
1498
1499         /*
1500          * Note: Normally one would think that we have to delete index tuples
1501          * associated with the heap tuple now..
1502          *
1503          * ... but in POSTGRES, we have no need to do this because the vacuum
1504          * daemon automatically opens an index scan and deletes index tuples
1505          * when it finds deleted heap tuples. -cim 9/27/89
1506          */
1507
1508         /* AFTER ROW DELETE Triggers */
1509         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1510 }
1511
1512 /* ----------------------------------------------------------------
1513  *              ExecUpdate
1514  *
1515  *              note: we can't run UPDATE queries with transactions
1516  *              off because UPDATEs are actually INSERTs and our
1517  *              scan will mistakenly loop forever, updating the tuple
1518  *              it just inserted..      This should be fixed but until it
1519  *              is, we don't want to get stuck in an infinite loop
1520  *              which corrupts your database..
1521  * ----------------------------------------------------------------
1522  */
1523 static void
1524 ExecUpdate(TupleTableSlot *slot,
1525                    ItemPointer tupleid,
1526                    EState *estate)
1527 {
1528         HeapTuple       tuple;
1529         ResultRelInfo *resultRelInfo;
1530         Relation        resultRelationDesc;
1531         ItemPointerData ctid;
1532         int                     result;
1533         int                     numIndices;
1534
1535         /*
1536          * abort the operation if not running transactions
1537          */
1538         if (IsBootstrapProcessingMode())
1539                 elog(ERROR, "cannot UPDATE during bootstrap");
1540
1541         /*
1542          * get the heap tuple out of the tuple table slot
1543          */
1544         tuple = slot->val;
1545
1546         /*
1547          * get information on the (current) result relation
1548          */
1549         resultRelInfo = estate->es_result_relation_info;
1550         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1551
1552         /* BEFORE ROW UPDATE Triggers */
1553         if (resultRelInfo->ri_TrigDesc &&
1554           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1555         {
1556                 HeapTuple       newtuple;
1557
1558                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1559                                                                                 tupleid, tuple,
1560                                                                                 estate->es_snapshot->curcid);
1561
1562                 if (newtuple == NULL)   /* "do nothing" */
1563                         return;
1564
1565                 if (newtuple != tuple)  /* modified by Trigger(s) */
1566                 {
1567                         /*
1568                          * Insert modified tuple into tuple table slot, replacing the
1569                          * original.  We assume that it was allocated in per-tuple
1570                          * memory context, and therefore will go away by itself. The
1571                          * tuple table slot should not try to clear it.
1572                          */
1573                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1574                         tuple = newtuple;
1575                 }
1576         }
1577
1578         /*
1579          * Check the constraints of the tuple
1580          *
1581          * If we generate a new candidate tuple after EvalPlanQual testing, we
1582          * must loop back here and recheck constraints.  (We don't need to
1583          * redo triggers, however.      If there are any BEFORE triggers then
1584          * trigger.c will have done mark4update to lock the correct tuple, so
1585          * there's no need to do them again.)
1586          */
1587 lreplace:;
1588         if (resultRelationDesc->rd_att->constr)
1589                 ExecConstraints(resultRelInfo, slot, estate);
1590
1591         /*
1592          * replace the heap tuple
1593          */
1594         result = heap_update(resultRelationDesc, tupleid, tuple,
1595                                                  &ctid,
1596                                                  estate->es_snapshot->curcid,
1597                                                  estate->es_crosscheck_snapshot,
1598                                                  true /* wait for commit */);
1599         switch (result)
1600         {
1601                 case HeapTupleSelfUpdated:
1602                         /* already deleted by self; nothing to do */
1603                         return;
1604
1605                 case HeapTupleMayBeUpdated:
1606                         break;
1607
1608                 case HeapTupleUpdated:
1609                         if (IsXactIsoLevelSerializable)
1610                                 ereport(ERROR,
1611                                                 (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
1612                                                  errmsg("could not serialize access due to concurrent update")));
1613                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1614                         {
1615                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1616                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1617
1618                                 if (!TupIsNull(epqslot))
1619                                 {
1620                                         *tupleid = ctid;
1621                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1622                                         slot = ExecStoreTuple(tuple,
1623                                                                         estate->es_junkFilter->jf_resultSlot,
1624                                                                                   InvalidBuffer, true);
1625                                         goto lreplace;
1626                                 }
1627                         }
1628                         /* tuple already deleted; nothing to do */
1629                         return;
1630
1631                 default:
1632                         elog(ERROR, "unrecognized heap_update status: %u", result);
1633                         return;
1634         }
1635
1636         IncrReplaced();
1637         (estate->es_processed)++;
1638
1639         /*
1640          * Note: instead of having to update the old index tuples associated
1641          * with the heap tuple, all we do is form and insert new index tuples.
1642          * This is because UPDATEs are actually DELETEs and INSERTs and index
1643          * tuple deletion is done automagically by the vacuum daemon. All we
1644          * do is insert new index tuples.  -cim 9/27/89
1645          */
1646
1647         /*
1648          * process indices
1649          *
1650          * heap_update updates a tuple in the base relation by invalidating it
1651          * and then inserting a new tuple to the relation.      As a side effect,
1652          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1653          * field.  So we now insert index tuples using the new tupleid stored
1654          * there.
1655          */
1656
1657         numIndices = resultRelInfo->ri_NumIndices;
1658         if (numIndices > 0)
1659                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1660
1661         /* AFTER ROW UPDATE Triggers */
1662         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1663 }
1664
1665 static const char *
1666 ExecRelCheck(ResultRelInfo *resultRelInfo,
1667                          TupleTableSlot *slot, EState *estate)
1668 {
1669         Relation        rel = resultRelInfo->ri_RelationDesc;
1670         int                     ncheck = rel->rd_att->constr->num_check;
1671         ConstrCheck *check = rel->rd_att->constr->check;
1672         ExprContext *econtext;
1673         MemoryContext oldContext;
1674         List       *qual;
1675         int                     i;
1676
1677         /*
1678          * If first time through for this result relation, build expression
1679          * nodetrees for rel's constraint expressions.  Keep them in the
1680          * per-query memory context so they'll survive throughout the query.
1681          */
1682         if (resultRelInfo->ri_ConstraintExprs == NULL)
1683         {
1684                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1685                 resultRelInfo->ri_ConstraintExprs =
1686                         (List **) palloc(ncheck * sizeof(List *));
1687                 for (i = 0; i < ncheck; i++)
1688                 {
1689                         /* ExecQual wants implicit-AND form */
1690                         qual = make_ands_implicit(stringToNode(check[i].ccbin));
1691                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1692                                 ExecPrepareExpr((Expr *) qual, estate);
1693                 }
1694                 MemoryContextSwitchTo(oldContext);
1695         }
1696
1697         /*
1698          * We will use the EState's per-tuple context for evaluating
1699          * constraint expressions (creating it if it's not already there).
1700          */
1701         econtext = GetPerTupleExprContext(estate);
1702
1703         /* Arrange for econtext's scan tuple to be the tuple under test */
1704         econtext->ecxt_scantuple = slot;
1705
1706         /* And evaluate the constraints */
1707         for (i = 0; i < ncheck; i++)
1708         {
1709                 qual = resultRelInfo->ri_ConstraintExprs[i];
1710
1711                 /*
1712                  * NOTE: SQL92 specifies that a NULL result from a constraint
1713                  * expression is not to be treated as a failure.  Therefore, tell
1714                  * ExecQual to return TRUE for NULL.
1715                  */
1716                 if (!ExecQual(qual, econtext, true))
1717                         return check[i].ccname;
1718         }
1719
1720         /* NULL result means no error */
1721         return NULL;
1722 }
1723
1724 void
1725 ExecConstraints(ResultRelInfo *resultRelInfo,
1726                                 TupleTableSlot *slot, EState *estate)
1727 {
1728         Relation        rel = resultRelInfo->ri_RelationDesc;
1729         HeapTuple       tuple = slot->val;
1730         TupleConstr *constr = rel->rd_att->constr;
1731
1732         Assert(constr);
1733
1734         if (constr->has_not_null)
1735         {
1736                 int                     natts = rel->rd_att->natts;
1737                 int                     attrChk;
1738
1739                 for (attrChk = 1; attrChk <= natts; attrChk++)
1740                 {
1741                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1742                                 heap_attisnull(tuple, attrChk))
1743                                 ereport(ERROR,
1744                                                 (errcode(ERRCODE_NOT_NULL_VIOLATION),
1745                                                  errmsg("null value in column \"%s\" violates not-null constraint",
1746                                         NameStr(rel->rd_att->attrs[attrChk - 1]->attname))));
1747                 }
1748         }
1749
1750         if (constr->num_check > 0)
1751         {
1752                 const char *failed;
1753
1754                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1755                         ereport(ERROR,
1756                                         (errcode(ERRCODE_CHECK_VIOLATION),
1757                                          errmsg("new row for relation \"%s\" violates check constraint \"%s\"",
1758                                                         RelationGetRelationName(rel), failed)));
1759         }
1760 }
1761
1762 /*
1763  * Check a modified tuple to see if we want to process its updated version
1764  * under READ COMMITTED rules.
1765  *
1766  * See backend/executor/README for some info about how this works.
1767  */
1768 TupleTableSlot *
1769 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1770 {
1771         evalPlanQual *epq;
1772         EState     *epqstate;
1773         Relation        relation;
1774         HeapTupleData tuple;
1775         HeapTuple       copyTuple = NULL;
1776         bool            endNode;
1777
1778         Assert(rti != 0);
1779
1780         /*
1781          * find relation containing target tuple
1782          */
1783         if (estate->es_result_relation_info != NULL &&
1784                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1785                 relation = estate->es_result_relation_info->ri_RelationDesc;
1786         else
1787         {
1788                 ListCell   *l;
1789
1790                 relation = NULL;
1791                 foreach(l, estate->es_rowMark)
1792                 {
1793                         if (((execRowMark *) lfirst(l))->rti == rti)
1794                         {
1795                                 relation = ((execRowMark *) lfirst(l))->relation;
1796                                 break;
1797                         }
1798                 }
1799                 if (relation == NULL)
1800                         elog(ERROR, "could not find RowMark for RT index %u", rti);
1801         }
1802
1803         /*
1804          * fetch tid tuple
1805          *
1806          * Loop here to deal with updated or busy tuples
1807          */
1808         tuple.t_self = *tid;
1809         for (;;)
1810         {
1811                 Buffer          buffer;
1812
1813                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1814                 {
1815                         TransactionId xwait = SnapshotDirty->xmax;
1816
1817                         /* xmin should not be dirty... */
1818                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1819                                 elog(ERROR, "t_xmin is uncommitted in tuple to be updated");
1820
1821                         /*
1822                          * If tuple is being updated by other transaction then we have
1823                          * to wait for its commit/abort.
1824                          */
1825                         if (TransactionIdIsValid(xwait))
1826                         {
1827                                 ReleaseBuffer(buffer);
1828                                 XactLockTableWait(xwait);
1829                                 continue;
1830                         }
1831
1832                         /*
1833                          * We got tuple - now copy it for use by recheck query.
1834                          */
1835                         copyTuple = heap_copytuple(&tuple);
1836                         ReleaseBuffer(buffer);
1837                         break;
1838                 }
1839
1840                 /*
1841                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1842                  * Note that it's possible to get invalid SnapshotDirty->tid if
1843                  * tuple updated by this transaction. Have we to check this ?
1844                  */
1845                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1846                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1847                 {
1848                         /* updated, so look at the updated copy */
1849                         tuple.t_self = SnapshotDirty->tid;
1850                         continue;
1851                 }
1852
1853                 /*
1854                  * Deleted or updated by this transaction; forget it.
1855                  */
1856                 return NULL;
1857         }
1858
1859         /*
1860          * For UPDATE/DELETE we have to return tid of actual row we're
1861          * executing PQ for.
1862          */
1863         *tid = tuple.t_self;
1864
1865         /*
1866          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1867          */
1868         epq = estate->es_evalPlanQual;
1869         endNode = true;
1870
1871         if (epq != NULL && epq->rti == 0)
1872         {
1873                 /* Top PQ stack entry is idle, so re-use it */
1874                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1875                 epq->rti = rti;
1876                 endNode = false;
1877         }
1878
1879         /*
1880          * If this is request for another RTE - Ra, - then we have to check
1881          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1882          * updated again and we have to re-start old execution for Ra and
1883          * forget all what we done after Ra was suspended. Cool? -:))
1884          */
1885         if (epq != NULL && epq->rti != rti &&
1886                 epq->estate->es_evTuple[rti - 1] != NULL)
1887         {
1888                 do
1889                 {
1890                         evalPlanQual *oldepq;
1891
1892                         /* stop execution */
1893                         EvalPlanQualStop(epq);
1894                         /* pop previous PlanQual from the stack */
1895                         oldepq = epq->next;
1896                         Assert(oldepq && oldepq->rti != 0);
1897                         /* push current PQ to freePQ stack */
1898                         oldepq->free = epq;
1899                         epq = oldepq;
1900                         estate->es_evalPlanQual = epq;
1901                 } while (epq->rti != rti);
1902         }
1903
1904         /*
1905          * If we are requested for another RTE then we have to suspend
1906          * execution of current PlanQual and start execution for new one.
1907          */
1908         if (epq == NULL || epq->rti != rti)
1909         {
1910                 /* try to reuse plan used previously */
1911                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1912
1913                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1914                 {
1915                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1916                         newepq->free = NULL;
1917                         newepq->estate = NULL;
1918                         newepq->planstate = NULL;
1919                 }
1920                 else
1921                 {
1922                         /* recycle previously used PlanQual */
1923                         Assert(newepq->estate == NULL);
1924                         epq->free = NULL;
1925                 }
1926                 /* push current PQ to the stack */
1927                 newepq->next = epq;
1928                 epq = newepq;
1929                 estate->es_evalPlanQual = epq;
1930                 epq->rti = rti;
1931                 endNode = false;
1932         }
1933
1934         Assert(epq->rti == rti);
1935
1936         /*
1937          * Ok - we're requested for the same RTE.  Unfortunately we still have
1938          * to end and restart execution of the plan, because ExecReScan
1939          * wouldn't ensure that upper plan nodes would reset themselves.  We
1940          * could make that work if insertion of the target tuple were
1941          * integrated with the Param mechanism somehow, so that the upper plan
1942          * nodes know that their children's outputs have changed.
1943          *
1944          * Note that the stack of free evalPlanQual nodes is quite useless at the
1945          * moment, since it only saves us from pallocing/releasing the
1946          * evalPlanQual nodes themselves.  But it will be useful once we
1947          * implement ReScan instead of end/restart for re-using PlanQual
1948          * nodes.
1949          */
1950         if (endNode)
1951         {
1952                 /* stop execution */
1953                 EvalPlanQualStop(epq);
1954         }
1955
1956         /*
1957          * Initialize new recheck query.
1958          *
1959          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need to
1960          * instead copy down changeable state from the top plan (including
1961          * es_result_relation_info, es_junkFilter) and reset locally
1962          * changeable state in the epq (including es_param_exec_vals,
1963          * es_evTupleNull).
1964          */
1965         EvalPlanQualStart(epq, estate, epq->next);
1966
1967         /*
1968          * free old RTE' tuple, if any, and store target tuple where
1969          * relation's scan node will see it
1970          */
1971         epqstate = epq->estate;
1972         if (epqstate->es_evTuple[rti - 1] != NULL)
1973                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1974         epqstate->es_evTuple[rti - 1] = copyTuple;
1975
1976         return EvalPlanQualNext(estate);
1977 }
1978
1979 static TupleTableSlot *
1980 EvalPlanQualNext(EState *estate)
1981 {
1982         evalPlanQual *epq = estate->es_evalPlanQual;
1983         MemoryContext oldcontext;
1984         TupleTableSlot *slot;
1985
1986         Assert(epq->rti != 0);
1987
1988 lpqnext:;
1989         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1990         slot = ExecProcNode(epq->planstate);
1991         MemoryContextSwitchTo(oldcontext);
1992
1993         /*
1994          * No more tuples for this PQ. Continue previous one.
1995          */
1996         if (TupIsNull(slot))
1997         {
1998                 evalPlanQual *oldepq;
1999
2000                 /* stop execution */
2001                 EvalPlanQualStop(epq);
2002                 /* pop old PQ from the stack */
2003                 oldepq = epq->next;
2004                 if (oldepq == NULL)
2005                 {
2006                         /* this is the first (oldest) PQ - mark as free */
2007                         epq->rti = 0;
2008                         estate->es_useEvalPlan = false;
2009                         /* and continue Query execution */
2010                         return (NULL);
2011                 }
2012                 Assert(oldepq->rti != 0);
2013                 /* push current PQ to freePQ stack */
2014                 oldepq->free = epq;
2015                 epq = oldepq;
2016                 estate->es_evalPlanQual = epq;
2017                 goto lpqnext;
2018         }
2019
2020         return (slot);
2021 }
2022
2023 static void
2024 EndEvalPlanQual(EState *estate)
2025 {
2026         evalPlanQual *epq = estate->es_evalPlanQual;
2027
2028         if (epq->rti == 0)                      /* plans already shutdowned */
2029         {
2030                 Assert(epq->next == NULL);
2031                 return;
2032         }
2033
2034         for (;;)
2035         {
2036                 evalPlanQual *oldepq;
2037
2038                 /* stop execution */
2039                 EvalPlanQualStop(epq);
2040                 /* pop old PQ from the stack */
2041                 oldepq = epq->next;
2042                 if (oldepq == NULL)
2043                 {
2044                         /* this is the first (oldest) PQ - mark as free */
2045                         epq->rti = 0;
2046                         estate->es_useEvalPlan = false;
2047                         break;
2048                 }
2049                 Assert(oldepq->rti != 0);
2050                 /* push current PQ to freePQ stack */
2051                 oldepq->free = epq;
2052                 epq = oldepq;
2053                 estate->es_evalPlanQual = epq;
2054         }
2055 }
2056
2057 /*
2058  * Start execution of one level of PlanQual.
2059  *
2060  * This is a cut-down version of ExecutorStart(): we copy some state from
2061  * the top-level estate rather than initializing it fresh.
2062  */
2063 static void
2064 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
2065 {
2066         EState     *epqstate;
2067         int                     rtsize;
2068         MemoryContext oldcontext;
2069
2070         rtsize = length(estate->es_range_table);
2071
2072         epq->estate = epqstate = CreateExecutorState();
2073
2074         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2075
2076         /*
2077          * The epqstates share the top query's copy of unchanging state such
2078          * as the snapshot, rangetable, result-rel info, and external Param
2079          * info. They need their own copies of local state, including a tuple
2080          * table, es_param_exec_vals, etc.
2081          */
2082         epqstate->es_direction = ForwardScanDirection;
2083         epqstate->es_snapshot = estate->es_snapshot;
2084         epqstate->es_crosscheck_snapshot = estate->es_crosscheck_snapshot;
2085         epqstate->es_range_table = estate->es_range_table;
2086         epqstate->es_result_relations = estate->es_result_relations;
2087         epqstate->es_num_result_relations = estate->es_num_result_relations;
2088         epqstate->es_result_relation_info = estate->es_result_relation_info;
2089         epqstate->es_junkFilter = estate->es_junkFilter;
2090         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2091         epqstate->es_param_list_info = estate->es_param_list_info;
2092         if (estate->es_topPlan->nParamExec > 0)
2093                 epqstate->es_param_exec_vals = (ParamExecData *)
2094                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2095         epqstate->es_rowMark = estate->es_rowMark;
2096         epqstate->es_instrument = estate->es_instrument;
2097         epqstate->es_select_into = estate->es_select_into;
2098         epqstate->es_into_oids = estate->es_into_oids;
2099         epqstate->es_topPlan = estate->es_topPlan;
2100
2101         /*
2102          * Each epqstate must have its own es_evTupleNull state, but all the
2103          * stack entries share es_evTuple state.  This allows sub-rechecks to
2104          * inherit the value being examined by an outer recheck.
2105          */
2106         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2107         if (priorepq == NULL)
2108                 /* first PQ stack entry */
2109                 epqstate->es_evTuple = (HeapTuple *)
2110                         palloc0(rtsize * sizeof(HeapTuple));
2111         else
2112                 /* later stack entries share the same storage */
2113                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2114
2115         epqstate->es_tupleTable =
2116                 ExecCreateTupleTable(estate->es_tupleTable->size);
2117
2118         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2119
2120         MemoryContextSwitchTo(oldcontext);
2121 }
2122
2123 /*
2124  * End execution of one level of PlanQual.
2125  *
2126  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2127  * of the normal cleanup, but *not* close result relations (which we are
2128  * just sharing from the outer query).
2129  */
2130 static void
2131 EvalPlanQualStop(evalPlanQual *epq)
2132 {
2133         EState     *epqstate = epq->estate;
2134         MemoryContext oldcontext;
2135
2136         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2137
2138         ExecEndNode(epq->planstate);
2139
2140         ExecDropTupleTable(epqstate->es_tupleTable, true);
2141         epqstate->es_tupleTable = NULL;
2142
2143         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2144         {
2145                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2146                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2147         }
2148
2149         MemoryContextSwitchTo(oldcontext);
2150
2151         FreeExecutorState(epqstate);
2152
2153         epq->estate = NULL;
2154         epq->planstate = NULL;
2155 }