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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 and the execution state is required
  16  *       as arguments
  17  *
  18  *      ExecutorStart() must be called at the beginning of any execution of any
  19  *      query plan and ExecutorEnd() should always be called at the end of
  20  *      execution of a plan.
  21  *
  22  *      ExecutorRun accepts direction and count arguments that specify whether
  23  *      the plan is to be executed forwards, backwards, and for how many tuples.
  24  *
  25  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  26  * Portions Copyright (c) 1994, Regents of the University of California
  27  *
  28  *
  29  * IDENTIFICATION
  30  *        $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.151 2002/03/02 21:39:25 momjian Exp $
  31  *
  32  *-------------------------------------------------------------------------
  33  */
  34 #include "postgres.h"
  35
  36 #include "access/heapam.h"
  37 #include "catalog/heap.h"
  38 #include "commands/command.h"
  39 #include "commands/trigger.h"
  40 #include "executor/execdebug.h"
  41 #include "executor/execdefs.h"
  42 #include "miscadmin.h"
  43 #include "optimizer/var.h"
  44 #include "parser/parsetree.h"
  45 #include "utils/acl.h"
  46
  47
  48 /* decls for local routines only used within this module */
  49 static TupleDesc InitPlan(CmdType operation,
  50                  Query *parseTree,
  51                  Plan *plan,
  52                  EState *estate);
  53 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  54                                   Index resultRelationIndex,
  55                                   List *rangeTable,
  56                                   CmdType operation);
  57 static void EndPlan(Plan *plan, EState *estate);
  58 static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
  59                         CmdType operation,
  60                         long numberTuples,
  61                         ScanDirection direction,
  62                         DestReceiver *destfunc);
  63 static void ExecRetrieve(TupleTableSlot *slot,
  64                          DestReceiver *destfunc,
  65                          EState *estate);
  66 static void ExecAppend(TupleTableSlot *slot, ItemPointer tupleid,
  67                    EState *estate);
  68 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  69                    EState *estate);
  70 static void ExecReplace(TupleTableSlot *slot, ItemPointer tupleid,
  71                         EState *estate);
  72 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  73 static void EndEvalPlanQual(EState *estate);
  74 static void ExecCheckQueryPerms(CmdType operation, Query *parseTree,
  75                                         Plan *plan);
  76 static void ExecCheckPlanPerms(Plan *plan, List *rangeTable,
  77                                    CmdType operation);
  78 static void ExecCheckRTPerms(List *rangeTable, CmdType operation);
  79 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
  80
  81 /* end of local decls */
  82
  83
  84 /* ----------------------------------------------------------------
  85  *              ExecutorStart
  86  *
  87  *              This routine must be called at the beginning of any execution of any
  88  *              query plan
  89  *
  90  *              returns a TupleDesc which describes the attributes of the tuples to
  91  *              be returned by the query.  (Same value is saved in queryDesc)
  92  *
  93  * NB: the CurrentMemoryContext when this is called must be the context
  94  * to be used as the per-query context for the query plan.      ExecutorRun()
  95  * and ExecutorEnd() must be called in this same memory context.
  96  * ----------------------------------------------------------------
  97  */
  98 TupleDesc
  99 ExecutorStart(QueryDesc *queryDesc, EState *estate)
 100 {
 101         TupleDesc       result;
 102
 103         /* sanity checks */
 104         Assert(queryDesc != NULL);
 105
 106         if (queryDesc->plantree->nParamExec > 0)
 107         {
 108                 estate->es_param_exec_vals = (ParamExecData *)
 109                         palloc(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 110                 MemSet(estate->es_param_exec_vals, 0,
 111                            queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 112         }
 113
 114         /*
 115          * Make our own private copy of the current queries snapshot data
 116          */
 117         if (QuerySnapshot == NULL)
 118                 estate->es_snapshot = NULL;
 119         else
 120         {
 121                 estate->es_snapshot = (Snapshot) palloc(sizeof(SnapshotData));
 122                 memcpy(estate->es_snapshot, QuerySnapshot, sizeof(SnapshotData));
 123                 if (estate->es_snapshot->xcnt > 0)
 124                 {
 125                         estate->es_snapshot->xip = (TransactionId *)
 126                                 palloc(estate->es_snapshot->xcnt * sizeof(TransactionId));
 127                         memcpy(estate->es_snapshot->xip, QuerySnapshot->xip,
 128                                    estate->es_snapshot->xcnt * sizeof(TransactionId));
 129                 }
 130         }
 131
 132         /*
 133          * Initialize the plan
 134          */
 135         result = InitPlan(queryDesc->operation,
 136                                           queryDesc->parsetree,
 137                                           queryDesc->plantree,
 138                                           estate);
 139
 140         queryDesc->tupDesc = result;
 141
 142         return result;
 143 }
 144
 145 /* ----------------------------------------------------------------
 146  *              ExecutorRun
 147  *
 148  *              This is the main routine of the executor module. It accepts
 149  *              the query descriptor from the traffic cop and executes the
 150  *              query plan.
 151  *
 152  *              ExecutorStart must have been called already.
 153  *
 154  *              If direction is NoMovementScanDirection then nothing is done
 155  *              except to start up/shut down the destination.  Otherwise,
 156  *              we retrieve up to 'count' tuples in the specified direction.
 157  *
 158  *              Note: count = 0 is interpreted as "no limit".
 159  *
 160  * ----------------------------------------------------------------
 161  */
 162 TupleTableSlot *
 163 ExecutorRun(QueryDesc *queryDesc, EState *estate,
 164                         ScanDirection direction, long count)
 165 {
 166         CmdType         operation;
 167         Plan       *plan;
 168         CommandDest dest;
 169         DestReceiver *destfunc;
 170         TupleTableSlot *result;
 171
 172         /*
 173          * sanity checks
 174          */
 175         Assert(queryDesc != NULL);
 176
 177         /*
 178          * extract information from the query descriptor and the query
 179          * feature.
 180          */
 181         operation = queryDesc->operation;
 182         plan = queryDesc->plantree;
 183         dest = queryDesc->dest;
 184
 185         /*
 186          * startup tuple receiver
 187          */
 188         estate->es_processed = 0;
 189         estate->es_lastoid = InvalidOid;
 190
 191         destfunc = DestToFunction(dest);
 192         (*destfunc->setup) (destfunc, (int) operation,
 193                                                 queryDesc->portalName, queryDesc->tupDesc);
 194
 195         /*
 196          * run plan
 197          */
 198         if (direction == NoMovementScanDirection)
 199                 result = NULL;
 200         else
 201                 result = ExecutePlan(estate,
 202                                                          plan,
 203                                                          operation,
 204                                                          count,
 205                                                          direction,
 206                                                          destfunc);
 207
 208         /*
 209          * shutdown receiver
 210          */
 211         (*destfunc->cleanup) (destfunc);
 212
 213         return result;
 214 }
 215
 216 /* ----------------------------------------------------------------
 217  *              ExecutorEnd
 218  *
 219  *              This routine must be called at the end of execution of any
 220  *              query plan
 221  * ----------------------------------------------------------------
 222  */
 223 void
 224 ExecutorEnd(QueryDesc *queryDesc, EState *estate)
 225 {
 226         /* sanity checks */
 227         Assert(queryDesc != NULL);
 228
 229         EndPlan(queryDesc->plantree, estate);
 230
 231         if (estate->es_snapshot != NULL)
 232         {
 233                 if (estate->es_snapshot->xcnt > 0)
 234                         pfree(estate->es_snapshot->xip);
 235                 pfree(estate->es_snapshot);
 236                 estate->es_snapshot = NULL;
 237         }
 238
 239         if (estate->es_param_exec_vals != NULL)
 240         {
 241                 pfree(estate->es_param_exec_vals);
 242                 estate->es_param_exec_vals = NULL;
 243         }
 244 }
 245
 246
 247 /*
 248  * ExecCheckQueryPerms
 249  *              Check access permissions for all relations referenced in a query.
 250  */
 251 static void
 252 ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
 253 {
 254         /*
 255          * Check RTEs in the query's primary rangetable.
 256          */
 257         ExecCheckRTPerms(parseTree->rtable, operation);
 258
 259         /*
 260          * Search for subplans and APPEND nodes to check their rangetables.
 261          */
 262         ExecCheckPlanPerms(plan, parseTree->rtable, operation);
 263 }
 264
 265 /*
 266  * ExecCheckPlanPerms
 267  *              Recursively scan the plan tree to check access permissions in
 268  *              subplans.
 269  */
 270 static void
 271 ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
 272 {
 273         List       *subp;
 274
 275         if (plan == NULL)
 276                 return;
 277
 278         /* Check subplans, which we assume are plain SELECT queries */
 279
 280         foreach(subp, plan->initPlan)
 281         {
 282                 SubPlan    *subplan = (SubPlan *) lfirst(subp);
 283
 284                 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 285                 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
 286         }
 287         foreach(subp, plan->subPlan)
 288         {
 289                 SubPlan    *subplan = (SubPlan *) lfirst(subp);
 290
 291                 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 292                 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
 293         }
 294
 295         /* Check lower plan nodes */
 296
 297         ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
 298         ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
 299
 300         /* Do node-type-specific checks */
 301
 302         switch (nodeTag(plan))
 303         {
 304                 case T_SubqueryScan:
 305                         {
 306                                 SubqueryScan *scan = (SubqueryScan *) plan;
 307                                 RangeTblEntry *rte;
 308
 309                                 /* Recursively check the subquery */
 310                                 rte = rt_fetch(scan->scan.scanrelid, rangeTable);
 311                                 Assert(rte->subquery != NULL);
 312                                 ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
 313                                 break;
 314                         }
 315                 case T_Append:
 316                         {
 317                                 Append     *app = (Append *) plan;
 318                                 List       *appendplans;
 319
 320                                 foreach(appendplans, app->appendplans)
 321                                 {
 322                                         ExecCheckPlanPerms((Plan *) lfirst(appendplans),
 323                                                                            rangeTable,
 324                                                                            operation);
 325                                 }
 326                                 break;
 327                         }
 328
 329                 default:
 330                         break;
 331         }
 332 }
 333
 334 /*
 335  * ExecCheckRTPerms
 336  *              Check access permissions for all relations listed in a range table.
 337  */
 338 static void
 339 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 340 {
 341         List       *lp;
 342
 343         foreach(lp, rangeTable)
 344         {
 345                 RangeTblEntry *rte = lfirst(lp);
 346
 347                 ExecCheckRTEPerms(rte, operation);
 348         }
 349 }
 350
 351 /*
 352  * ExecCheckRTEPerms
 353  *              Check access permissions for a single RTE.
 354  */
 355 static void
 356 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 357 {
 358         char       *relName;
 359         Oid                     userid;
 360         int32           aclcheck_result;
 361
 362         /*
 363          * If it's a subquery RTE, ignore it --- it will be checked when
 364          * ExecCheckPlanPerms finds the SubqueryScan node for it.
 365          */
 366         if (rte->subquery)
 367                 return;
 368
 369         relName = rte->relname;
 370
 371         /*
 372          * userid to check as: current user unless we have a setuid
 373          * indication.
 374          *
 375          * Note: GetUserId() is presently fast enough that there's no harm in
 376          * calling it separately for each RTE.  If that stops being true, we
 377          * could call it once in ExecCheckQueryPerms and pass the userid down
 378          * from there.  But for now, no need for the extra clutter.
 379          */
 380         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 381
 382 #define CHECK(MODE)             pg_aclcheck(relName, userid, MODE)
 383
 384         if (rte->checkForRead)
 385         {
 386                 aclcheck_result = CHECK(ACL_SELECT);
 387                 if (aclcheck_result != ACLCHECK_OK)
 388                         elog(ERROR, "%s: %s",
 389                                  relName, aclcheck_error_strings[aclcheck_result]);
 390         }
 391
 392         if (rte->checkForWrite)
 393         {
 394                 /*
 395                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 396                  * Right now we don't distinguish that from true update as far as
 397                  * permissions checks are concerned.
 398                  */
 399                 switch (operation)
 400                 {
 401                         case CMD_INSERT:
 402                                 aclcheck_result = CHECK(ACL_INSERT);
 403                                 break;
 404                         case CMD_SELECT:
 405                         case CMD_UPDATE:
 406                                 aclcheck_result = CHECK(ACL_UPDATE);
 407                                 break;
 408                         case CMD_DELETE:
 409                                 aclcheck_result = CHECK(ACL_DELETE);
 410                                 break;
 411                         default:
 412                                 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
 413                                          operation);
 414                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 415                                 break;
 416                 }
 417                 if (aclcheck_result != ACLCHECK_OK)
 418                         elog(ERROR, "%s: %s",
 419                                  relName, aclcheck_error_strings[aclcheck_result]);
 420         }
 421 }
 422
 423
 424 /* ===============================================================
 425  * ===============================================================
 426                                                  static routines follow
 427  * ===============================================================
 428  * ===============================================================
 429  */
 430
 431 typedef struct execRowMark
 432 {
 433         Relation        relation;
 434         Index           rti;
 435         char            resname[32];
 436 } execRowMark;
 437
 438 typedef struct evalPlanQual
 439 {
 440         Plan       *plan;
 441         Index           rti;
 442         EState          estate;
 443         struct evalPlanQual *free;
 444 } evalPlanQual;
 445
 446 /* ----------------------------------------------------------------
 447  *              InitPlan
 448  *
 449  *              Initializes the query plan: open files, allocate storage
 450  *              and start up the rule manager
 451  * ----------------------------------------------------------------
 452  */
 453 static TupleDesc
 454 InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
 455 {
 456         List       *rangeTable;
 457         Relation        intoRelationDesc;
 458         TupleDesc       tupType;
 459
 460         /*
 461          * Do permissions checks.
 462          */
 463         ExecCheckQueryPerms(operation, parseTree, plan);
 464
 465         /*
 466          * get information from query descriptor
 467          */
 468         rangeTable = parseTree->rtable;
 469
 470         /*
 471          * initialize the node's execution state
 472          */
 473         estate->es_range_table = rangeTable;
 474
 475         /*
 476          * if there is a result relation, initialize result relation stuff
 477          */
 478         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 479         {
 480                 List       *resultRelations = parseTree->resultRelations;
 481                 int                     numResultRelations;
 482                 ResultRelInfo *resultRelInfos;
 483
 484                 if (resultRelations != NIL)
 485                 {
 486                         /*
 487                          * Multiple result relations (due to inheritance)
 488                          * parseTree->resultRelations identifies them all
 489                          */
 490                         ResultRelInfo *resultRelInfo;
 491
 492                         numResultRelations = length(resultRelations);
 493                         resultRelInfos = (ResultRelInfo *)
 494                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 495                         resultRelInfo = resultRelInfos;
 496                         while (resultRelations != NIL)
 497                         {
 498                                 initResultRelInfo(resultRelInfo,
 499                                                                   lfirsti(resultRelations),
 500                                                                   rangeTable,
 501                                                                   operation);
 502                                 resultRelInfo++;
 503                                 resultRelations = lnext(resultRelations);
 504                         }
 505                 }
 506                 else
 507                 {
 508                         /*
 509                          * Single result relation identified by
 510                          * parseTree->resultRelation
 511                          */
 512                         numResultRelations = 1;
 513                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 514                         initResultRelInfo(resultRelInfos,
 515                                                           parseTree->resultRelation,
 516                                                           rangeTable,
 517                                                           operation);
 518                 }
 519
 520                 estate->es_result_relations = resultRelInfos;
 521                 estate->es_num_result_relations = numResultRelations;
 522                 /* Initialize to first or only result rel */
 523                 estate->es_result_relation_info = resultRelInfos;
 524         }
 525         else
 526         {
 527                 /*
 528                  * if no result relation, then set state appropriately
 529                  */
 530                 estate->es_result_relations = NULL;
 531                 estate->es_num_result_relations = 0;
 532                 estate->es_result_relation_info = NULL;
 533         }
 534
 535         /*
 536          * Have to lock relations selected for update
 537          */
 538         estate->es_rowMark = NIL;
 539         if (parseTree->rowMarks != NIL)
 540         {
 541                 List       *l;
 542
 543                 foreach(l, parseTree->rowMarks)
 544                 {
 545                         Index           rti = lfirsti(l);
 546                         Oid                     relid = getrelid(rti, rangeTable);
 547                         Relation        relation;
 548                         execRowMark *erm;
 549
 550                         relation = heap_open(relid, RowShareLock);
 551                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 552                         erm->relation = relation;
 553                         erm->rti = rti;
 554                         sprintf(erm->resname, "ctid%u", rti);
 555                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 556                 }
 557         }
 558
 559         /*
 560          * initialize the executor "tuple" table.  We need slots for all the
 561          * plan nodes, plus possibly output slots for the junkfilter(s). At
 562          * this point we aren't sure if we need junkfilters, so just add slots
 563          * for them unconditionally.
 564          */
 565         {
 566                 int                     nSlots = ExecCountSlotsNode(plan);
 567
 568                 if (parseTree->resultRelations != NIL)
 569                         nSlots += length(parseTree->resultRelations);
 570                 else
 571                         nSlots += 1;
 572                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 573         }
 574
 575         /* mark EvalPlanQual not active */
 576         estate->es_origPlan = plan;
 577         estate->es_evalPlanQual = NULL;
 578         estate->es_evTuple = NULL;
 579         estate->es_evTupleNull = NULL;
 580         estate->es_useEvalPlan = false;
 581
 582         /*
 583          * initialize the private state information for all the nodes in the
 584          * query tree.  This opens files, allocates storage and leaves us
 585          * ready to start processing tuples.
 586          */
 587         ExecInitNode(plan, estate, NULL);
 588
 589         /*
 590          * Get the tuple descriptor describing the type of tuples to return.
 591          * (this is especially important if we are creating a relation with
 592          * "retrieve into")
 593          */
 594         tupType = ExecGetTupType(plan);         /* tuple descriptor */
 595
 596         /*
 597          * Initialize the junk filter if needed. SELECT and INSERT queries
 598          * need a filter if there are any junk attrs in the tlist.      UPDATE and
 599          * DELETE always need one, since there's always a junk 'ctid'
 600          * attribute present --- no need to look first.
 601          */
 602         {
 603                 bool            junk_filter_needed = false;
 604                 List       *tlist;
 605
 606                 switch (operation)
 607                 {
 608                         case CMD_SELECT:
 609                         case CMD_INSERT:
 610                                 foreach(tlist, plan->targetlist)
 611                                 {
 612                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 613
 614                                         if (tle->resdom->resjunk)
 615                                         {
 616                                                 junk_filter_needed = true;
 617                                                 break;
 618                                         }
 619                                 }
 620                                 break;
 621                         case CMD_UPDATE:
 622                         case CMD_DELETE:
 623                                 junk_filter_needed = true;
 624                                 break;
 625                         default:
 626                                 break;
 627                 }
 628
 629                 if (junk_filter_needed)
 630                 {
 631                         /*
 632                          * If there are multiple result relations, each one needs its
 633                          * own junk filter.  Note this is only possible for
 634                          * UPDATE/DELETE, so we can't be fooled by some needing a
 635                          * filter and some not.
 636                          */
 637                         if (parseTree->resultRelations != NIL)
 638                         {
 639                                 List       *subplans;
 640                                 ResultRelInfo *resultRelInfo;
 641
 642                                 /* Top plan had better be an Append here. */
 643                                 Assert(IsA(plan, Append));
 644                                 Assert(((Append *) plan)->isTarget);
 645                                 subplans = ((Append *) plan)->appendplans;
 646                                 Assert(length(subplans) == estate->es_num_result_relations);
 647                                 resultRelInfo = estate->es_result_relations;
 648                                 while (subplans != NIL)
 649                                 {
 650                                         Plan       *subplan = (Plan *) lfirst(subplans);
 651                                         JunkFilter *j;
 652
 653                                         j = ExecInitJunkFilter(subplan->targetlist,
 654                                                                                    ExecGetTupType(subplan),
 655                                                           ExecAllocTableSlot(estate->es_tupleTable));
 656                                         resultRelInfo->ri_junkFilter = j;
 657                                         resultRelInfo++;
 658                                         subplans = lnext(subplans);
 659                                 }
 660
 661                                 /*
 662                                  * Set active junkfilter too; at this point ExecInitAppend
 663                                  * has already selected an active result relation...
 664                                  */
 665                                 estate->es_junkFilter =
 666                                         estate->es_result_relation_info->ri_junkFilter;
 667                         }
 668                         else
 669                         {
 670                                 /* Normal case with just one JunkFilter */
 671                                 JunkFilter *j;
 672
 673                                 j = ExecInitJunkFilter(plan->targetlist,
 674                                                                            tupType,
 675                                                           ExecAllocTableSlot(estate->es_tupleTable));
 676                                 estate->es_junkFilter = j;
 677                                 if (estate->es_result_relation_info)
 678                                         estate->es_result_relation_info->ri_junkFilter = j;
 679
 680                                 /* For SELECT, want to return the cleaned tuple type */
 681                                 if (operation == CMD_SELECT)
 682                                         tupType = j->jf_cleanTupType;
 683                         }
 684                 }
 685                 else
 686                         estate->es_junkFilter = NULL;
 687         }
 688
 689         /*
 690          * initialize the "into" relation
 691          */
 692         intoRelationDesc = (Relation) NULL;
 693
 694         if (operation == CMD_SELECT)
 695         {
 696                 char       *intoName;
 697                 Oid                     intoRelationId;
 698                 TupleDesc       tupdesc;
 699
 700                 if (!parseTree->isPortal)
 701                 {
 702                         /*
 703                          * a select into table
 704                          */
 705                         if (parseTree->into != NULL)
 706                         {
 707                                 /*
 708                                  * create the "into" relation
 709                                  */
 710                                 intoName = parseTree->into;
 711
 712                                 /*
 713                                  * have to copy tupType to get rid of constraints
 714                                  */
 715                                 tupdesc = CreateTupleDescCopy(tupType);
 716
 717                                 intoRelationId =
 718                                         heap_create_with_catalog(intoName,
 719                                                                                          tupdesc,
 720                                                                                          RELKIND_RELATION, true,
 721                                                                                          parseTree->isTemp,
 722                                                                                          allowSystemTableMods);
 723
 724                                 FreeTupleDesc(tupdesc);
 725
 726                                 /*
 727                                  * Advance command counter so that the newly-created
 728                                  * relation's catalog tuples will be visible to heap_open.
 729                                  */
 730                                 CommandCounterIncrement();
 731
 732                                 /*
 733                                  * If necessary, create a TOAST table for the into
 734                                  * relation. Note that AlterTableCreateToastTable ends
 735                                  * with CommandCounterIncrement(), so that the TOAST table
 736                                  * will be visible for insertion.
 737                                  */
 738                                 AlterTableCreateToastTable(intoName, true);
 739
 740                                 intoRelationDesc = heap_open(intoRelationId,
 741                                                                                          AccessExclusiveLock);
 742                         }
 743                 }
 744         }
 745
 746         estate->es_into_relation_descriptor = intoRelationDesc;
 747
 748         return tupType;
 749 }
 750
 751 /*
 752  * Initialize ResultRelInfo data for one result relation
 753  */
 754 static void
 755 initResultRelInfo(ResultRelInfo *resultRelInfo,
 756                                   Index resultRelationIndex,
 757                                   List *rangeTable,
 758                                   CmdType operation)
 759 {
 760         Oid                     resultRelationOid;
 761         Relation        resultRelationDesc;
 762
 763         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 764         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 765
 766         switch (resultRelationDesc->rd_rel->relkind)
 767         {
 768                 case RELKIND_SEQUENCE:
 769                         elog(ERROR, "You can't change sequence relation %s",
 770                                  RelationGetRelationName(resultRelationDesc));
 771                         break;
 772                 case RELKIND_TOASTVALUE:
 773                         elog(ERROR, "You can't change toast relation %s",
 774                                  RelationGetRelationName(resultRelationDesc));
 775                         break;
 776                 case RELKIND_VIEW:
 777                         elog(ERROR, "You can't change view relation %s",
 778                                  RelationGetRelationName(resultRelationDesc));
 779                         break;
 780         }
 781
 782         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 783         resultRelInfo->type = T_ResultRelInfo;
 784         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 785         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 786         resultRelInfo->ri_NumIndices = 0;
 787         resultRelInfo->ri_IndexRelationDescs = NULL;
 788         resultRelInfo->ri_IndexRelationInfo = NULL;
 789         resultRelInfo->ri_TrigDesc = resultRelationDesc->trigdesc;
 790         resultRelInfo->ri_TrigFunctions = NULL;
 791         resultRelInfo->ri_ConstraintExprs = NULL;
 792         resultRelInfo->ri_junkFilter = NULL;
 793
 794         /*
 795          * If there are indices on the result relation, open them and save
 796          * descriptors in the result relation info, so that we can add new
 797          * index entries for the tuples we add/update.  We need not do this
 798          * for a DELETE, however, since deletion doesn't affect indexes.
 799          */
 800         if (resultRelationDesc->rd_rel->relhasindex &&
 801                 operation != CMD_DELETE)
 802                 ExecOpenIndices(resultRelInfo);
 803 }
 804
 805 /* ----------------------------------------------------------------
 806  *              EndPlan
 807  *
 808  *              Cleans up the query plan -- closes files and free up storages
 809  * ----------------------------------------------------------------
 810  */
 811 static void
 812 EndPlan(Plan *plan, EState *estate)
 813 {
 814         ResultRelInfo *resultRelInfo;
 815         int                     i;
 816         List       *l;
 817
 818         /*
 819          * shut down any PlanQual processing we were doing
 820          */
 821         if (estate->es_evalPlanQual != NULL)
 822                 EndEvalPlanQual(estate);
 823
 824         /*
 825          * shut down the node-type-specific query processing
 826          */
 827         ExecEndNode(plan, NULL);
 828
 829         /*
 830          * destroy the executor "tuple" table.
 831          */
 832         ExecDropTupleTable(estate->es_tupleTable, true);
 833         estate->es_tupleTable = NULL;
 834
 835         /*
 836          * close the result relation(s) if any, but hold locks until xact
 837          * commit.      Also clean up junkfilters if present.
 838          */
 839         resultRelInfo = estate->es_result_relations;
 840         for (i = estate->es_num_result_relations; i > 0; i--)
 841         {
 842                 /* Close indices and then the relation itself */
 843                 ExecCloseIndices(resultRelInfo);
 844                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 845                 /* Delete the junkfilter if any */
 846                 if (resultRelInfo->ri_junkFilter != NULL)
 847                         ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
 848                 resultRelInfo++;
 849         }
 850
 851         /*
 852          * close the "into" relation if necessary, again keeping lock
 853          */
 854         if (estate->es_into_relation_descriptor != NULL)
 855                 heap_close(estate->es_into_relation_descriptor, NoLock);
 856
 857         /*
 858          * There might be a junkfilter without a result relation.
 859          */
 860         if (estate->es_num_result_relations == 0 &&
 861                 estate->es_junkFilter != NULL)
 862         {
 863                 ExecFreeJunkFilter(estate->es_junkFilter);
 864                 estate->es_junkFilter = NULL;
 865         }
 866
 867         /*
 868          * close any relations selected FOR UPDATE, again keeping locks
 869          */
 870         foreach(l, estate->es_rowMark)
 871         {
 872                 execRowMark *erm = lfirst(l);
 873
 874                 heap_close(erm->relation, NoLock);
 875         }
 876 }
 877
 878 /* ----------------------------------------------------------------
 879  *              ExecutePlan
 880  *
 881  *              processes the query plan to retrieve 'numberTuples' tuples in the
 882  *              direction specified.
 883  *              Retrieves all tuples if numberTuples is 0
 884  *
 885  *              result is either a slot containing the last tuple in the case
 886  *              of a RETRIEVE or NULL otherwise.
 887  *
 888  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 889  * user can see it
 890  * ----------------------------------------------------------------
 891  */
 892 static TupleTableSlot *
 893 ExecutePlan(EState *estate,
 894                         Plan *plan,
 895                         CmdType operation,
 896                         long numberTuples,
 897                         ScanDirection direction,
 898                         DestReceiver *destfunc)
 899 {
 900         JunkFilter *junkfilter;
 901         TupleTableSlot *slot;
 902         ItemPointer tupleid = NULL;
 903         ItemPointerData tuple_ctid;
 904         long            current_tuple_count;
 905         TupleTableSlot *result;
 906
 907         /*
 908          * initialize local variables
 909          */
 910         slot = NULL;
 911         current_tuple_count = 0;
 912         result = NULL;
 913
 914         /*
 915          * Set the direction.
 916          */
 917         estate->es_direction = direction;
 918
 919         /*
 920          * Loop until we've processed the proper number of tuples from the
 921          * plan.
 922          */
 923
 924         for (;;)
 925         {
 926                 /* Reset the per-output-tuple exprcontext */
 927                 ResetPerTupleExprContext(estate);
 928
 929                 /*
 930                  * Execute the plan and obtain a tuple
 931                  */
 932 lnext:  ;
 933                 if (estate->es_useEvalPlan)
 934                 {
 935                         slot = EvalPlanQualNext(estate);
 936                         if (TupIsNull(slot))
 937                                 slot = ExecProcNode(plan, NULL);
 938                 }
 939                 else
 940                         slot = ExecProcNode(plan, NULL);
 941
 942                 /*
 943                  * if the tuple is null, then we assume there is nothing more to
 944                  * process so we just return null...
 945                  */
 946                 if (TupIsNull(slot))
 947                 {
 948                         result = NULL;
 949                         break;
 950                 }
 951
 952                 /*
 953                  * if we have a junk filter, then project a new tuple with the
 954                  * junk removed.
 955                  *
 956                  * Store this new "clean" tuple in the junkfilter's resultSlot.
 957                  * (Formerly, we stored it back over the "dirty" tuple, which is
 958                  * WRONG because that tuple slot has the wrong descriptor.)
 959                  *
 960                  * Also, extract all the junk information we need.
 961                  */
 962                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
 963                 {
 964                         Datum           datum;
 965                         HeapTuple       newTuple;
 966                         bool            isNull;
 967
 968                         /*
 969                          * extract the 'ctid' junk attribute.
 970                          */
 971                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
 972                         {
 973                                 if (!ExecGetJunkAttribute(junkfilter,
 974                                                                                   slot,
 975                                                                                   "ctid",
 976                                                                                   &datum,
 977                                                                                   &isNull))
 978                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
 979
 980                                 /* shouldn't ever get a null result... */
 981                                 if (isNull)
 982                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
 983
 984                                 tupleid = (ItemPointer) DatumGetPointer(datum);
 985                                 tuple_ctid = *tupleid;  /* make sure we don't free the
 986                                                                                  * ctid!! */
 987                                 tupleid = &tuple_ctid;
 988                         }
 989                         else if (estate->es_rowMark != NIL)
 990                         {
 991                                 List       *l;
 992
 993                 lmark:  ;
 994                                 foreach(l, estate->es_rowMark)
 995                                 {
 996                                         execRowMark *erm = lfirst(l);
 997                                         Buffer          buffer;
 998                                         HeapTupleData tuple;
 999                                         TupleTableSlot *newSlot;
1000                                         int                     test;
1001
1002                                         if (!ExecGetJunkAttribute(junkfilter,
1003                                                                                           slot,
1004                                                                                           erm->resname,
1005                                                                                           &datum,
1006                                                                                           &isNull))
1007                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1008                                                          erm->resname);
1009
1010                                         /* shouldn't ever get a null result... */
1011                                         if (isNull)
1012                                                 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1013                                                          erm->resname);
1014
1015                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1016                                         test = heap_mark4update(erm->relation, &tuple, &buffer);
1017                                         ReleaseBuffer(buffer);
1018                                         switch (test)
1019                                         {
1020                                                 case HeapTupleSelfUpdated:
1021                                                 case HeapTupleMayBeUpdated:
1022                                                         break;
1023
1024                                                 case HeapTupleUpdated:
1025                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1026                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1027                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1028                                                                   (ItemPointer) DatumGetPointer(datum))))
1029                                                         {
1030                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1031                                                                 if (!(TupIsNull(newSlot)))
1032                                                                 {
1033                                                                         slot = newSlot;
1034                                                                         estate->es_useEvalPlan = true;
1035                                                                         goto lmark;
1036                                                                 }
1037                                                         }
1038
1039                                                         /*
1040                                                          * if tuple was deleted or PlanQual failed for
1041                                                          * updated tuple - we must not return this
1042                                                          * tuple!
1043                                                          */
1044                                                         goto lnext;
1045
1046                                                 default:
1047                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1048                                                         return (NULL);
1049                                         }
1050                                 }
1051                         }
1052
1053                         /*
1054                          * Finally create a new "clean" tuple with all junk attributes
1055                          * removed
1056                          */
1057                         newTuple = ExecRemoveJunk(junkfilter, slot);
1058
1059                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1060                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1061                                                                   InvalidBuffer,                /* this tuple has no
1062                                                                                                                  * buffer */
1063                                                                   true);                /* tuple should be pfreed */
1064                 }                                               /* if (junkfilter... */
1065
1066                 /*
1067                  * now that we have a tuple, do the appropriate thing with it..
1068                  * either return it to the user, add it to a relation someplace,
1069                  * delete it from a relation, or modify some of its attributes.
1070                  */
1071
1072                 switch (operation)
1073                 {
1074                         case CMD_SELECT:
1075                                 ExecRetrieve(slot,              /* slot containing tuple */
1076                                                          destfunc,      /* destination's tuple-receiver
1077                                                                                  * obj */
1078                                                          estate);       /* */
1079                                 result = slot;
1080                                 break;
1081
1082                         case CMD_INSERT:
1083                                 ExecAppend(slot, tupleid, estate);
1084                                 result = NULL;
1085                                 break;
1086
1087                         case CMD_DELETE:
1088                                 ExecDelete(slot, tupleid, estate);
1089                                 result = NULL;
1090                                 break;
1091
1092                         case CMD_UPDATE:
1093                                 ExecReplace(slot, tupleid, estate);
1094                                 result = NULL;
1095                                 break;
1096
1097                         default:
1098                                 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1099                                 result = NULL;
1100                                 break;
1101                 }
1102
1103                 /*
1104                  * check our tuple count.. if we've processed the proper number
1105                  * then quit, else loop again and process more tuples..
1106                  */
1107                 current_tuple_count++;
1108                 if (numberTuples == current_tuple_count)
1109                         break;
1110         }
1111
1112         /*
1113          * here, result is either a slot containing a tuple in the case of a
1114          * RETRIEVE or NULL otherwise.
1115          */
1116         return result;
1117 }
1118
1119 /* ----------------------------------------------------------------
1120  *              ExecRetrieve
1121  *
1122  *              RETRIEVEs are easy.. we just pass the tuple to the appropriate
1123  *              print function.  The only complexity is when we do a
1124  *              "retrieve into", in which case we insert the tuple into
1125  *              the appropriate relation (note: this is a newly created relation
1126  *              so we don't need to worry about indices or locks.)
1127  * ----------------------------------------------------------------
1128  */
1129 static void
1130 ExecRetrieve(TupleTableSlot *slot,
1131                          DestReceiver *destfunc,
1132                          EState *estate)
1133 {
1134         HeapTuple       tuple;
1135         TupleDesc       attrtype;
1136
1137         /*
1138          * get the heap tuple out of the tuple table slot
1139          */
1140         tuple = slot->val;
1141         attrtype = slot->ttc_tupleDescriptor;
1142
1143         /*
1144          * insert the tuple into the "into relation"
1145          */
1146         if (estate->es_into_relation_descriptor != NULL)
1147         {
1148                 heap_insert(estate->es_into_relation_descriptor, tuple);
1149                 IncrAppended();
1150         }
1151
1152         /*
1153          * send the tuple to the front end (or the screen)
1154          */
1155         (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1156         IncrRetrieved();
1157         (estate->es_processed)++;
1158 }
1159
1160 /* ----------------------------------------------------------------
1161  *              ExecAppend
1162  *
1163  *              APPENDs are trickier.. we have to insert the tuple into
1164  *              the base relation and insert appropriate tuples into the
1165  *              index relations.
1166  * ----------------------------------------------------------------
1167  */
1168
1169 static void
1170 ExecAppend(TupleTableSlot *slot,
1171                    ItemPointer tupleid,
1172                    EState *estate)
1173 {
1174         HeapTuple       tuple;
1175         ResultRelInfo *resultRelInfo;
1176         Relation        resultRelationDesc;
1177         int                     numIndices;
1178         Oid                     newId;
1179
1180         /*
1181          * get the heap tuple out of the tuple table slot
1182          */
1183         tuple = slot->val;
1184
1185         /*
1186          * get information on the (current) result relation
1187          */
1188         resultRelInfo = estate->es_result_relation_info;
1189         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1190
1191         /* BEFORE ROW INSERT Triggers */
1192         if (resultRelInfo->ri_TrigDesc &&
1193           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1194         {
1195                 HeapTuple       newtuple;
1196
1197                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1198
1199                 if (newtuple == NULL)   /* "do nothing" */
1200                         return;
1201
1202                 if (newtuple != tuple)  /* modified by Trigger(s) */
1203                 {
1204                         /*
1205                          * Insert modified tuple into tuple table slot, replacing the
1206                          * original.  We assume that it was allocated in per-tuple
1207                          * memory context, and therefore will go away by itself. The
1208                          * tuple table slot should not try to clear it.
1209                          */
1210                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1211                         tuple = newtuple;
1212                 }
1213         }
1214
1215         /*
1216          * Check the constraints of the tuple
1217          */
1218         if (resultRelationDesc->rd_att->constr)
1219                 ExecConstraints("ExecAppend", resultRelInfo, slot, estate);
1220
1221         /*
1222          * insert the tuple
1223          */
1224         newId = heap_insert(resultRelationDesc, tuple);
1225
1226         IncrAppended();
1227         (estate->es_processed)++;
1228         estate->es_lastoid = newId;
1229         setLastTid(&(tuple->t_self));
1230
1231         /*
1232          * process indices
1233          *
1234          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1235          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1236          * field.
1237          */
1238         numIndices = resultRelInfo->ri_NumIndices;
1239         if (numIndices > 0)
1240                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1241
1242         /* AFTER ROW INSERT Triggers */
1243         if (resultRelInfo->ri_TrigDesc)
1244                 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1245 }
1246
1247 /* ----------------------------------------------------------------
1248  *              ExecDelete
1249  *
1250  *              DELETE is like append, we delete the tuple and its
1251  *              index tuples.
1252  * ----------------------------------------------------------------
1253  */
1254 static void
1255 ExecDelete(TupleTableSlot *slot,
1256                    ItemPointer tupleid,
1257                    EState *estate)
1258 {
1259         ResultRelInfo *resultRelInfo;
1260         Relation        resultRelationDesc;
1261         ItemPointerData ctid;
1262         int                     result;
1263
1264         /*
1265          * get information on the (current) result relation
1266          */
1267         resultRelInfo = estate->es_result_relation_info;
1268         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1269
1270         /* BEFORE ROW DELETE Triggers */
1271         if (resultRelInfo->ri_TrigDesc &&
1272           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1273         {
1274                 bool            dodelete;
1275
1276                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
1277
1278                 if (!dodelete)                  /* "do nothing" */
1279                         return;
1280         }
1281
1282         /*
1283          * delete the tuple
1284          */
1285 ldelete:;
1286         result = heap_delete(resultRelationDesc, tupleid, &ctid);
1287         switch (result)
1288         {
1289                 case HeapTupleSelfUpdated:
1290                         return;
1291
1292                 case HeapTupleMayBeUpdated:
1293                         break;
1294
1295                 case HeapTupleUpdated:
1296                         if (XactIsoLevel == XACT_SERIALIZABLE)
1297                                 elog(ERROR, "Can't serialize access due to concurrent update");
1298                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1299                         {
1300                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1301                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1302
1303                                 if (!TupIsNull(epqslot))
1304                                 {
1305                                         *tupleid = ctid;
1306                                         goto ldelete;
1307                                 }
1308                         }
1309                         /* tuple already deleted; nothing to do */
1310                         return;
1311
1312                 default:
1313                         elog(ERROR, "Unknown status %u from heap_delete", result);
1314                         return;
1315         }
1316
1317         IncrDeleted();
1318         (estate->es_processed)++;
1319
1320         /*
1321          * Note: Normally one would think that we have to delete index tuples
1322          * associated with the heap tuple now..
1323          *
1324          * ... but in POSTGRES, we have no need to do this because the vacuum
1325          * daemon automatically opens an index scan and deletes index tuples
1326          * when it finds deleted heap tuples. -cim 9/27/89
1327          */
1328
1329         /* AFTER ROW DELETE Triggers */
1330         if (resultRelInfo->ri_TrigDesc)
1331                 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1332 }
1333
1334 /* ----------------------------------------------------------------
1335  *              ExecReplace
1336  *
1337  *              note: we can't run replace queries with transactions
1338  *              off because replaces are actually appends and our
1339  *              scan will mistakenly loop forever, replacing the tuple
1340  *              it just appended..      This should be fixed but until it
1341  *              is, we don't want to get stuck in an infinite loop
1342  *              which corrupts your database..
1343  * ----------------------------------------------------------------
1344  */
1345 static void
1346 ExecReplace(TupleTableSlot *slot,
1347                         ItemPointer tupleid,
1348                         EState *estate)
1349 {
1350         HeapTuple       tuple;
1351         ResultRelInfo *resultRelInfo;
1352         Relation        resultRelationDesc;
1353         ItemPointerData ctid;
1354         int                     result;
1355         int                     numIndices;
1356
1357         /*
1358          * abort the operation if not running transactions
1359          */
1360         if (IsBootstrapProcessingMode())
1361         {
1362                 elog(NOTICE, "ExecReplace: replace can't run without transactions");
1363                 return;
1364         }
1365
1366         /*
1367          * get the heap tuple out of the tuple table slot
1368          */
1369         tuple = slot->val;
1370
1371         /*
1372          * get information on the (current) result relation
1373          */
1374         resultRelInfo = estate->es_result_relation_info;
1375         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1376
1377         /* BEFORE ROW UPDATE Triggers */
1378         if (resultRelInfo->ri_TrigDesc &&
1379           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1380         {
1381                 HeapTuple       newtuple;
1382
1383                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1384                                                                                 tupleid, tuple);
1385
1386                 if (newtuple == NULL)   /* "do nothing" */
1387                         return;
1388
1389                 if (newtuple != tuple)  /* modified by Trigger(s) */
1390                 {
1391                         /*
1392                          * Insert modified tuple into tuple table slot, replacing the
1393                          * original.  We assume that it was allocated in per-tuple
1394                          * memory context, and therefore will go away by itself. The
1395                          * tuple table slot should not try to clear it.
1396                          */
1397                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1398                         tuple = newtuple;
1399                 }
1400         }
1401
1402         /*
1403          * Check the constraints of the tuple
1404          *
1405          * If we generate a new candidate tuple after EvalPlanQual testing, we
1406          * must loop back here and recheck constraints.  (We don't need to
1407          * redo triggers, however.      If there are any BEFORE triggers then
1408          * trigger.c will have done mark4update to lock the correct tuple, so
1409          * there's no need to do them again.)
1410          */
1411 lreplace:;
1412         if (resultRelationDesc->rd_att->constr)
1413                 ExecConstraints("ExecReplace", resultRelInfo, slot, estate);
1414
1415         /*
1416          * replace the heap tuple
1417          */
1418         result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
1419         switch (result)
1420         {
1421                 case HeapTupleSelfUpdated:
1422                         return;
1423
1424                 case HeapTupleMayBeUpdated:
1425                         break;
1426
1427                 case HeapTupleUpdated:
1428                         if (XactIsoLevel == XACT_SERIALIZABLE)
1429                                 elog(ERROR, "Can't serialize access due to concurrent update");
1430                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1431                         {
1432                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1433                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1434
1435                                 if (!TupIsNull(epqslot))
1436                                 {
1437                                         *tupleid = ctid;
1438                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1439                                         slot = ExecStoreTuple(tuple,
1440                                                                         estate->es_junkFilter->jf_resultSlot,
1441                                                                                   InvalidBuffer, true);
1442                                         goto lreplace;
1443                                 }
1444                         }
1445                         /* tuple already deleted; nothing to do */
1446                         return;
1447
1448                 default:
1449                         elog(ERROR, "Unknown status %u from heap_update", result);
1450                         return;
1451         }
1452
1453         IncrReplaced();
1454         (estate->es_processed)++;
1455
1456         /*
1457          * Note: instead of having to update the old index tuples associated
1458          * with the heap tuple, all we do is form and insert new index tuples.
1459          * This is because replaces are actually deletes and inserts and index
1460          * tuple deletion is done automagically by the vacuum daemon. All we
1461          * do is insert new index tuples.  -cim 9/27/89
1462          */
1463
1464         /*
1465          * process indices
1466          *
1467          * heap_update updates a tuple in the base relation by invalidating it
1468          * and then appending a new tuple to the relation.      As a side effect,
1469          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1470          * field.  So we now insert index tuples using the new tupleid stored
1471          * there.
1472          */
1473
1474         numIndices = resultRelInfo->ri_NumIndices;
1475         if (numIndices > 0)
1476                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
1477
1478         /* AFTER ROW UPDATE Triggers */
1479         if (resultRelInfo->ri_TrigDesc)
1480                 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1481 }
1482
1483 static char *
1484 ExecRelCheck(ResultRelInfo *resultRelInfo,
1485                          TupleTableSlot *slot, EState *estate)
1486 {
1487         Relation        rel = resultRelInfo->ri_RelationDesc;
1488         int                     ncheck = rel->rd_att->constr->num_check;
1489         ConstrCheck *check = rel->rd_att->constr->check;
1490         ExprContext *econtext;
1491         MemoryContext oldContext;
1492         List       *qual;
1493         int                     i;
1494
1495         /*
1496          * If first time through for this result relation, build expression
1497          * nodetrees for rel's constraint expressions.  Keep them in the
1498          * per-query memory context so they'll survive throughout the query.
1499          */
1500         if (resultRelInfo->ri_ConstraintExprs == NULL)
1501         {
1502                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1503                 resultRelInfo->ri_ConstraintExprs =
1504                         (List **) palloc(ncheck * sizeof(List *));
1505                 for (i = 0; i < ncheck; i++)
1506                 {
1507                         qual = (List *) stringToNode(check[i].ccbin);
1508                         resultRelInfo->ri_ConstraintExprs[i] = qual;
1509                 }
1510                 MemoryContextSwitchTo(oldContext);
1511         }
1512
1513         /*
1514          * We will use the EState's per-tuple context for evaluating
1515          * constraint expressions (creating it if it's not already there).
1516          */
1517         econtext = GetPerTupleExprContext(estate);
1518
1519         /* Arrange for econtext's scan tuple to be the tuple under test */
1520         econtext->ecxt_scantuple = slot;
1521
1522         /* And evaluate the constraints */
1523         for (i = 0; i < ncheck; i++)
1524         {
1525                 qual = resultRelInfo->ri_ConstraintExprs[i];
1526
1527                 /*
1528                  * NOTE: SQL92 specifies that a NULL result from a constraint
1529                  * expression is not to be treated as a failure.  Therefore, tell
1530                  * ExecQual to return TRUE for NULL.
1531                  */
1532                 if (!ExecQual(qual, econtext, true))
1533                         return check[i].ccname;
1534         }
1535
1536         /* NULL result means no error */
1537         return (char *) NULL;
1538 }
1539
1540 void
1541 ExecConstraints(char *caller, ResultRelInfo *resultRelInfo,
1542                                 TupleTableSlot *slot, EState *estate)
1543 {
1544         Relation        rel = resultRelInfo->ri_RelationDesc;
1545         HeapTuple       tuple = slot->val;
1546         TupleConstr *constr = rel->rd_att->constr;
1547
1548         Assert(constr);
1549
1550         if (constr->has_not_null)
1551         {
1552                 int                     natts = rel->rd_att->natts;
1553                 int                     attrChk;
1554
1555                 for (attrChk = 1; attrChk <= natts; attrChk++)
1556                 {
1557                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1558                                 heap_attisnull(tuple, attrChk))
1559                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1560                                          caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1561                 }
1562         }
1563
1564         if (constr->num_check > 0)
1565         {
1566                 char       *failed;
1567
1568                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1569                         elog(ERROR, "%s: rejected due to CHECK constraint %s",
1570                                  caller, failed);
1571         }
1572 }
1573
1574 /*
1575  * Check a modified tuple to see if we want to process its updated version
1576  * under READ COMMITTED rules.
1577  *
1578  * See backend/executor/README for some info about how this works.
1579  */
1580 TupleTableSlot *
1581 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1582 {
1583         evalPlanQual *epq;
1584         EState     *epqstate;
1585         Relation        relation;
1586         HeapTupleData tuple;
1587         HeapTuple       copyTuple = NULL;
1588         int                     rtsize;
1589         bool            endNode;
1590
1591         Assert(rti != 0);
1592
1593         /*
1594          * find relation containing target tuple
1595          */
1596         if (estate->es_result_relation_info != NULL &&
1597                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1598                 relation = estate->es_result_relation_info->ri_RelationDesc;
1599         else
1600         {
1601                 List       *l;
1602
1603                 relation = NULL;
1604                 foreach(l, estate->es_rowMark)
1605                 {
1606                         if (((execRowMark *) lfirst(l))->rti == rti)
1607                         {
1608                                 relation = ((execRowMark *) lfirst(l))->relation;
1609                                 break;
1610                         }
1611                 }
1612                 if (relation == NULL)
1613                         elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1614         }
1615
1616         /*
1617          * fetch tid tuple
1618          *
1619          * Loop here to deal with updated or busy tuples
1620          */
1621         tuple.t_self = *tid;
1622         for (;;)
1623         {
1624                 Buffer          buffer;
1625
1626                 heap_fetch(relation, SnapshotDirty, &tuple, &buffer, NULL);
1627                 if (tuple.t_data != NULL)
1628                 {
1629                         TransactionId xwait = SnapshotDirty->xmax;
1630
1631                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1632                                 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1633
1634                         /*
1635                          * If tuple is being updated by other transaction then we have
1636                          * to wait for its commit/abort.
1637                          */
1638                         if (TransactionIdIsValid(xwait))
1639                         {
1640                                 ReleaseBuffer(buffer);
1641                                 XactLockTableWait(xwait);
1642                                 continue;
1643                         }
1644
1645                         /*
1646                          * We got tuple - now copy it for use by recheck query.
1647                          */
1648                         copyTuple = heap_copytuple(&tuple);
1649                         ReleaseBuffer(buffer);
1650                         break;
1651                 }
1652
1653                 /*
1654                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1655                  * Note that it's possible to get invalid SnapshotDirty->tid if
1656                  * tuple updated by this transaction. Have we to check this ?
1657                  */
1658                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1659                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1660                 {
1661                         /* updated, so look at the updated copy */
1662                         tuple.t_self = SnapshotDirty->tid;
1663                         continue;
1664                 }
1665
1666                 /*
1667                  * Deleted or updated by this transaction; forget it.
1668                  */
1669                 return NULL;
1670         }
1671
1672         /*
1673          * For UPDATE/DELETE we have to return tid of actual row we're
1674          * executing PQ for.
1675          */
1676         *tid = tuple.t_self;
1677
1678         /*
1679          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1680          */
1681         epq = (evalPlanQual *) estate->es_evalPlanQual;
1682         rtsize = length(estate->es_range_table);
1683         endNode = true;
1684
1685         if (epq != NULL && epq->rti == 0)
1686         {
1687                 /* Top PQ stack entry is idle, so re-use it */
1688                 Assert(!(estate->es_useEvalPlan) &&
1689                            epq->estate.es_evalPlanQual == NULL);
1690                 epq->rti = rti;
1691                 endNode = false;
1692         }
1693
1694         /*
1695          * If this is request for another RTE - Ra, - then we have to check
1696          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1697          * updated again and we have to re-start old execution for Ra and
1698          * forget all what we done after Ra was suspended. Cool? -:))
1699          */
1700         if (epq != NULL && epq->rti != rti &&
1701                 epq->estate.es_evTuple[rti - 1] != NULL)
1702         {
1703                 do
1704                 {
1705                         evalPlanQual *oldepq;
1706
1707                         /* pop previous PlanQual from the stack */
1708                         epqstate = &(epq->estate);
1709                         oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1710                         Assert(oldepq->rti != 0);
1711                         /* stop execution */
1712                         ExecEndNode(epq->plan, NULL);
1713                         ExecDropTupleTable(epqstate->es_tupleTable, true);
1714                         epqstate->es_tupleTable = NULL;
1715                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1716                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1717                         /* push current PQ to freePQ stack */
1718                         oldepq->free = epq;
1719                         epq = oldepq;
1720                         estate->es_evalPlanQual = (Pointer) epq;
1721                 } while (epq->rti != rti);
1722         }
1723
1724         /*
1725          * If we are requested for another RTE then we have to suspend
1726          * execution of current PlanQual and start execution for new one.
1727          */
1728         if (epq == NULL || epq->rti != rti)
1729         {
1730                 /* try to reuse plan used previously */
1731                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1732
1733                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1734                 {
1735                         newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1736                         newepq->free = NULL;
1737
1738                         /*
1739                          * Each stack level has its own copy of the plan tree.  This
1740                          * is wasteful, but necessary as long as plan nodes point to
1741                          * exec state nodes rather than vice versa.  Note that
1742                          * copyfuncs.c doesn't attempt to copy the exec state nodes,
1743                          * which is a good thing in this situation.
1744                          */
1745                         newepq->plan = copyObject(estate->es_origPlan);
1746
1747                         /*
1748                          * Init stack level's EState.  We share top level's copy of
1749                          * es_result_relations array and other non-changing status. We
1750                          * need our own tupletable, es_param_exec_vals, and other
1751                          * changeable state.
1752                          */
1753                         epqstate = &(newepq->estate);
1754                         memcpy(epqstate, estate, sizeof(EState));
1755                         epqstate->es_direction = ForwardScanDirection;
1756                         if (estate->es_origPlan->nParamExec > 0)
1757                                 epqstate->es_param_exec_vals = (ParamExecData *)
1758                                         palloc(estate->es_origPlan->nParamExec *
1759                                                    sizeof(ParamExecData));
1760                         epqstate->es_tupleTable = NULL;
1761                         epqstate->es_per_tuple_exprcontext = NULL;
1762
1763                         /*
1764                          * Each epqstate must have its own es_evTupleNull state, but
1765                          * all the stack entries share es_evTuple state.  This allows
1766                          * sub-rechecks to inherit the value being examined by an
1767                          * outer recheck.
1768                          */
1769                         epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
1770                         if (epq == NULL)
1771                         {
1772                                 /* first PQ stack entry */
1773                                 epqstate->es_evTuple = (HeapTuple *)
1774                                         palloc(rtsize * sizeof(HeapTuple));
1775                                 memset(epqstate->es_evTuple, 0, rtsize * sizeof(HeapTuple));
1776                         }
1777                         else
1778                         {
1779                                 /* later stack entries share the same storage */
1780                                 epqstate->es_evTuple = epq->estate.es_evTuple;
1781                         }
1782                 }
1783                 else
1784                 {
1785                         /* recycle previously used EState */
1786                         epqstate = &(newepq->estate);
1787                 }
1788                 /* push current PQ to the stack */
1789                 epqstate->es_evalPlanQual = (Pointer) epq;
1790                 epq = newepq;
1791                 estate->es_evalPlanQual = (Pointer) epq;
1792                 epq->rti = rti;
1793                 endNode = false;
1794         }
1795
1796         Assert(epq->rti == rti);
1797         epqstate = &(epq->estate);
1798
1799         /*
1800          * Ok - we're requested for the same RTE.  Unfortunately we still have
1801          * to end and restart execution of the plan, because ExecReScan
1802          * wouldn't ensure that upper plan nodes would reset themselves.  We
1803          * could make that work if insertion of the target tuple were
1804          * integrated with the Param mechanism somehow, so that the upper plan
1805          * nodes know that their children's outputs have changed.
1806          */
1807         if (endNode)
1808         {
1809                 /* stop execution */
1810                 ExecEndNode(epq->plan, NULL);
1811                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1812                 epqstate->es_tupleTable = NULL;
1813         }
1814
1815         /*
1816          * free old RTE' tuple, if any, and store target tuple where
1817          * relation's scan node will see it
1818          */
1819         if (epqstate->es_evTuple[rti - 1] != NULL)
1820                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1821         epqstate->es_evTuple[rti - 1] = copyTuple;
1822
1823         /*
1824          * Initialize for new recheck query; be careful to copy down state
1825          * that might have changed in top EState.
1826          */
1827         epqstate->es_result_relation_info = estate->es_result_relation_info;
1828         epqstate->es_junkFilter = estate->es_junkFilter;
1829         if (estate->es_origPlan->nParamExec > 0)
1830                 memset(epqstate->es_param_exec_vals, 0,
1831                            estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1832         memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
1833         epqstate->es_useEvalPlan = false;
1834         Assert(epqstate->es_tupleTable == NULL);
1835         epqstate->es_tupleTable =
1836                 ExecCreateTupleTable(estate->es_tupleTable->size);
1837
1838         ExecInitNode(epq->plan, epqstate, NULL);
1839
1840         return EvalPlanQualNext(estate);
1841 }
1842
1843 static TupleTableSlot *
1844 EvalPlanQualNext(EState *estate)
1845 {
1846         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1847         EState     *epqstate = &(epq->estate);
1848         evalPlanQual *oldepq;
1849         TupleTableSlot *slot;
1850
1851         Assert(epq->rti != 0);
1852
1853 lpqnext:;
1854         slot = ExecProcNode(epq->plan, NULL);
1855
1856         /*
1857          * No more tuples for this PQ. Continue previous one.
1858          */
1859         if (TupIsNull(slot))
1860         {
1861                 /* stop execution */
1862                 ExecEndNode(epq->plan, NULL);
1863                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1864                 epqstate->es_tupleTable = NULL;
1865                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1866                 epqstate->es_evTuple[epq->rti - 1] = NULL;
1867                 /* pop old PQ from the stack */
1868                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1869                 if (oldepq == (evalPlanQual *) NULL)
1870                 {
1871                         epq->rti = 0;           /* this is the first (oldest) */
1872                         estate->es_useEvalPlan = false;         /* PQ - mark as free and          */
1873                         return (NULL);          /* continue Query execution   */
1874                 }
1875                 Assert(oldepq->rti != 0);
1876                 /* push current PQ to freePQ stack */
1877                 oldepq->free = epq;
1878                 epq = oldepq;
1879                 epqstate = &(epq->estate);
1880                 estate->es_evalPlanQual = (Pointer) epq;
1881                 goto lpqnext;
1882         }
1883
1884         return (slot);
1885 }
1886
1887 static void
1888 EndEvalPlanQual(EState *estate)
1889 {
1890         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1891         EState     *epqstate = &(epq->estate);
1892         evalPlanQual *oldepq;
1893
1894         if (epq->rti == 0)                      /* plans already shutdowned */
1895         {
1896                 Assert(epq->estate.es_evalPlanQual == NULL);
1897                 return;
1898         }
1899
1900         for (;;)
1901         {
1902                 /* stop execution */
1903                 ExecEndNode(epq->plan, NULL);
1904                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1905                 epqstate->es_tupleTable = NULL;
1906                 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1907                 {
1908                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1909                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1910                 }
1911                 /* pop old PQ from the stack */
1912                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1913                 if (oldepq == (evalPlanQual *) NULL)
1914                 {
1915                         epq->rti = 0;           /* this is the first (oldest) */
1916                         estate->es_useEvalPlan = false;         /* PQ - mark as free */
1917                         break;
1918                 }
1919                 Assert(oldepq->rti != 0);
1920                 /* push current PQ to freePQ stack */
1921                 oldepq->free = epq;
1922                 epq = oldepq;
1923                 epqstate = &(epq->estate);
1924                 estate->es_evalPlanQual = (Pointer) epq;
1925         }
1926 }