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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 1.159 2002/04/27 03:45:02 tgl Exp $
  31  *
  32  *-------------------------------------------------------------------------
  33  */
  34 #include "postgres.h"
  35
  36 #include "access/heapam.h"
  37 #include "catalog/heap.h"
  38 #include "catalog/namespace.h"
  39 #include "commands/tablecmds.h"
  40 #include "commands/trigger.h"
  41 #include "executor/execdebug.h"
  42 #include "executor/execdefs.h"
  43 #include "miscadmin.h"
  44 #include "optimizer/var.h"
  45 #include "parser/parsetree.h"
  46 #include "utils/acl.h"
  47 #include "utils/lsyscache.h"
  48
  49
  50 /* decls for local routines only used within this module */
  51 static TupleDesc InitPlan(CmdType operation,
  52                  Query *parseTree,
  53                  Plan *plan,
  54                  EState *estate);
  55 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  56                                   Index resultRelationIndex,
  57                                   List *rangeTable,
  58                                   CmdType operation);
  59 static void EndPlan(Plan *plan, EState *estate);
  60 static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
  61                         CmdType operation,
  62                         long numberTuples,
  63                         ScanDirection direction,
  64                         DestReceiver *destfunc);
  65 static void ExecRetrieve(TupleTableSlot *slot,
  66                          DestReceiver *destfunc,
  67                          EState *estate);
  68 static void ExecAppend(TupleTableSlot *slot, ItemPointer tupleid,
  69                    EState *estate);
  70 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  71                    EState *estate);
  72 static void ExecReplace(TupleTableSlot *slot, ItemPointer tupleid,
  73                         EState *estate);
  74 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  75 static void EndEvalPlanQual(EState *estate);
  76 static void ExecCheckQueryPerms(CmdType operation, Query *parseTree,
  77                                         Plan *plan);
  78 static void ExecCheckPlanPerms(Plan *plan, List *rangeTable,
  79                                    CmdType operation);
  80 static void ExecCheckRTPerms(List *rangeTable, CmdType operation);
  81 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
  82
  83 /* end of local decls */
  84
  85
  86 /* ----------------------------------------------------------------
  87  *              ExecutorStart
  88  *
  89  *              This routine must be called at the beginning of any execution of any
  90  *              query plan
  91  *
  92  *              returns a TupleDesc which describes the attributes of the tuples to
  93  *              be returned by the query.  (Same value is saved in queryDesc)
  94  *
  95  * NB: the CurrentMemoryContext when this is called must be the context
  96  * to be used as the per-query context for the query plan.      ExecutorRun()
  97  * and ExecutorEnd() must be called in this same memory context.
  98  * ----------------------------------------------------------------
  99  */
 100 TupleDesc
 101 ExecutorStart(QueryDesc *queryDesc, EState *estate)
 102 {
 103         TupleDesc       result;
 104
 105         /* sanity checks */
 106         Assert(queryDesc != NULL);
 107
 108         if (queryDesc->plantree->nParamExec > 0)
 109         {
 110                 estate->es_param_exec_vals = (ParamExecData *)
 111                         palloc(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 112                 MemSet(estate->es_param_exec_vals, 0,
 113                            queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 114         }
 115
 116         /*
 117          * Make our own private copy of the current queries snapshot data
 118          */
 119         if (QuerySnapshot == NULL)
 120                 estate->es_snapshot = NULL;
 121         else
 122         {
 123                 estate->es_snapshot = (Snapshot) palloc(sizeof(SnapshotData));
 124                 memcpy(estate->es_snapshot, QuerySnapshot, sizeof(SnapshotData));
 125                 if (estate->es_snapshot->xcnt > 0)
 126                 {
 127                         estate->es_snapshot->xip = (TransactionId *)
 128                                 palloc(estate->es_snapshot->xcnt * sizeof(TransactionId));
 129                         memcpy(estate->es_snapshot->xip, QuerySnapshot->xip,
 130                                    estate->es_snapshot->xcnt * sizeof(TransactionId));
 131                 }
 132         }
 133
 134         /*
 135          * Initialize the plan
 136          */
 137         result = InitPlan(queryDesc->operation,
 138                                           queryDesc->parsetree,
 139                                           queryDesc->plantree,
 140                                           estate);
 141
 142         queryDesc->tupDesc = result;
 143
 144         return result;
 145 }
 146
 147 /* ----------------------------------------------------------------
 148  *              ExecutorRun
 149  *
 150  *              This is the main routine of the executor module. It accepts
 151  *              the query descriptor from the traffic cop and executes the
 152  *              query plan.
 153  *
 154  *              ExecutorStart must have been called already.
 155  *
 156  *              If direction is NoMovementScanDirection then nothing is done
 157  *              except to start up/shut down the destination.  Otherwise,
 158  *              we retrieve up to 'count' tuples in the specified direction.
 159  *
 160  *              Note: count = 0 is interpreted as no portal limit, e.g. run to
 161  *              completion.
 162  *
 163  * ----------------------------------------------------------------
 164  */
 165 TupleTableSlot *
 166 ExecutorRun(QueryDesc *queryDesc, EState *estate,
 167                         ScanDirection direction, long count)
 168 {
 169         CmdType         operation;
 170         Plan       *plan;
 171         CommandDest dest;
 172         DestReceiver *destfunc;
 173         TupleTableSlot *result;
 174
 175         /*
 176          * sanity checks
 177          */
 178         Assert(queryDesc != NULL);
 179
 180         /*
 181          * extract information from the query descriptor and the query
 182          * feature.
 183          */
 184         operation = queryDesc->operation;
 185         plan = queryDesc->plantree;
 186         dest = queryDesc->dest;
 187
 188         /*
 189          * startup tuple receiver
 190          */
 191         estate->es_processed = 0;
 192         estate->es_lastoid = InvalidOid;
 193
 194         destfunc = DestToFunction(dest);
 195         (*destfunc->setup) (destfunc, (int) operation,
 196                                                 queryDesc->portalName, queryDesc->tupDesc);
 197
 198         /*
 199          * run plan
 200          */
 201         if (direction == NoMovementScanDirection)
 202                 result = NULL;
 203         else
 204                 result = ExecutePlan(estate,
 205                                                          plan,
 206                                                          operation,
 207                                                          count,
 208                                                          direction,
 209                                                          destfunc);
 210
 211         /*
 212          * shutdown receiver
 213          */
 214         (*destfunc->cleanup) (destfunc);
 215
 216         return result;
 217 }
 218
 219 /* ----------------------------------------------------------------
 220  *              ExecutorEnd
 221  *
 222  *              This routine must be called at the end of execution of any
 223  *              query plan
 224  * ----------------------------------------------------------------
 225  */
 226 void
 227 ExecutorEnd(QueryDesc *queryDesc, EState *estate)
 228 {
 229         /* sanity checks */
 230         Assert(queryDesc != NULL);
 231
 232         EndPlan(queryDesc->plantree, estate);
 233
 234         if (estate->es_snapshot != NULL)
 235         {
 236                 if (estate->es_snapshot->xcnt > 0)
 237                         pfree(estate->es_snapshot->xip);
 238                 pfree(estate->es_snapshot);
 239                 estate->es_snapshot = NULL;
 240         }
 241
 242         if (estate->es_param_exec_vals != NULL)
 243         {
 244                 pfree(estate->es_param_exec_vals);
 245                 estate->es_param_exec_vals = NULL;
 246         }
 247 }
 248
 249
 250 /*
 251  * ExecCheckQueryPerms
 252  *              Check access permissions for all relations referenced in a query.
 253  */
 254 static void
 255 ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
 256 {
 257         /*
 258          * Check RTEs in the query's primary rangetable.
 259          */
 260         ExecCheckRTPerms(parseTree->rtable, operation);
 261
 262         /*
 263          * Search for subplans and APPEND nodes to check their rangetables.
 264          */
 265         ExecCheckPlanPerms(plan, parseTree->rtable, operation);
 266 }
 267
 268 /*
 269  * ExecCheckPlanPerms
 270  *              Recursively scan the plan tree to check access permissions in
 271  *              subplans.
 272  */
 273 static void
 274 ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
 275 {
 276         List       *subp;
 277
 278         if (plan == NULL)
 279                 return;
 280
 281         /* Check subplans, which we assume are plain SELECT queries */
 282
 283         foreach(subp, plan->initPlan)
 284         {
 285                 SubPlan    *subplan = (SubPlan *) lfirst(subp);
 286
 287                 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 288                 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
 289         }
 290         foreach(subp, plan->subPlan)
 291         {
 292                 SubPlan    *subplan = (SubPlan *) lfirst(subp);
 293
 294                 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 295                 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
 296         }
 297
 298         /* Check lower plan nodes */
 299
 300         ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
 301         ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
 302
 303         /* Do node-type-specific checks */
 304
 305         switch (nodeTag(plan))
 306         {
 307                 case T_SubqueryScan:
 308                         {
 309                                 SubqueryScan *scan = (SubqueryScan *) plan;
 310                                 RangeTblEntry *rte;
 311
 312                                 /* Recursively check the subquery */
 313                                 rte = rt_fetch(scan->scan.scanrelid, rangeTable);
 314                                 Assert(rte->subquery != NULL);
 315                                 ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
 316                                 break;
 317                         }
 318                 case T_Append:
 319                         {
 320                                 Append     *app = (Append *) plan;
 321                                 List       *appendplans;
 322
 323                                 foreach(appendplans, app->appendplans)
 324                                 {
 325                                         ExecCheckPlanPerms((Plan *) lfirst(appendplans),
 326                                                                            rangeTable,
 327                                                                            operation);
 328                                 }
 329                                 break;
 330                         }
 331
 332                 default:
 333                         break;
 334         }
 335 }
 336
 337 /*
 338  * ExecCheckRTPerms
 339  *              Check access permissions for all relations listed in a range table.
 340  */
 341 static void
 342 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 343 {
 344         List       *lp;
 345
 346         foreach(lp, rangeTable)
 347         {
 348                 RangeTblEntry *rte = lfirst(lp);
 349
 350                 ExecCheckRTEPerms(rte, operation);
 351         }
 352 }
 353
 354 /*
 355  * ExecCheckRTEPerms
 356  *              Check access permissions for a single RTE.
 357  */
 358 static void
 359 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 360 {
 361         Oid                     relOid;
 362         Oid                     userid;
 363         AclResult       aclcheck_result;
 364
 365         /*
 366          * If it's a subquery RTE, ignore it --- it will be checked when
 367          * ExecCheckPlanPerms finds the SubqueryScan node for it.
 368          */
 369         if (rte->rtekind != RTE_RELATION)
 370                 return;
 371
 372         relOid = rte->relid;
 373
 374         /*
 375          * userid to check as: current user unless we have a setuid
 376          * indication.
 377          *
 378          * Note: GetUserId() is presently fast enough that there's no harm in
 379          * calling it separately for each RTE.  If that stops being true, we
 380          * could call it once in ExecCheckQueryPerms and pass the userid down
 381          * from there.  But for now, no need for the extra clutter.
 382          */
 383         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 384
 385 #define CHECK(MODE)             pg_class_aclcheck(relOid, userid, MODE)
 386
 387         if (rte->checkForRead)
 388         {
 389                 aclcheck_result = CHECK(ACL_SELECT);
 390                 if (aclcheck_result != ACLCHECK_OK)
 391                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 392         }
 393
 394         if (rte->checkForWrite)
 395         {
 396                 /*
 397                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 398                  * Right now we don't distinguish that from true update as far as
 399                  * permissions checks are concerned.
 400                  */
 401                 switch (operation)
 402                 {
 403                         case CMD_INSERT:
 404                                 aclcheck_result = CHECK(ACL_INSERT);
 405                                 break;
 406                         case CMD_SELECT:
 407                         case CMD_UPDATE:
 408                                 aclcheck_result = CHECK(ACL_UPDATE);
 409                                 break;
 410                         case CMD_DELETE:
 411                                 aclcheck_result = CHECK(ACL_DELETE);
 412                                 break;
 413                         default:
 414                                 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
 415                                          operation);
 416                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 417                                 break;
 418                 }
 419                 if (aclcheck_result != ACLCHECK_OK)
 420                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 421         }
 422 }
 423
 424
 425 /* ===============================================================
 426  * ===============================================================
 427                                                  static routines follow
 428  * ===============================================================
 429  * ===============================================================
 430  */
 431
 432 typedef struct execRowMark
 433 {
 434         Relation        relation;
 435         Index           rti;
 436         char            resname[32];
 437 } execRowMark;
 438
 439 typedef struct evalPlanQual
 440 {
 441         Plan       *plan;
 442         Index           rti;
 443         EState          estate;
 444         struct evalPlanQual *free;
 445 } evalPlanQual;
 446
 447 /* ----------------------------------------------------------------
 448  *              InitPlan
 449  *
 450  *              Initializes the query plan: open files, allocate storage
 451  *              and start up the rule manager
 452  * ----------------------------------------------------------------
 453  */
 454 static TupleDesc
 455 InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
 456 {
 457         List       *rangeTable;
 458         Relation        intoRelationDesc;
 459         TupleDesc       tupType;
 460
 461         /*
 462          * Do permissions checks.
 463          */
 464         ExecCheckQueryPerms(operation, parseTree, plan);
 465
 466         /*
 467          * get information from query descriptor
 468          */
 469         rangeTable = parseTree->rtable;
 470
 471         /*
 472          * initialize the node's execution state
 473          */
 474         estate->es_range_table = rangeTable;
 475
 476         /*
 477          * if there is a result relation, initialize result relation stuff
 478          */
 479         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 480         {
 481                 List       *resultRelations = parseTree->resultRelations;
 482                 int                     numResultRelations;
 483                 ResultRelInfo *resultRelInfos;
 484
 485                 if (resultRelations != NIL)
 486                 {
 487                         /*
 488                          * Multiple result relations (due to inheritance)
 489                          * parseTree->resultRelations identifies them all
 490                          */
 491                         ResultRelInfo *resultRelInfo;
 492
 493                         numResultRelations = length(resultRelations);
 494                         resultRelInfos = (ResultRelInfo *)
 495                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 496                         resultRelInfo = resultRelInfos;
 497                         while (resultRelations != NIL)
 498                         {
 499                                 initResultRelInfo(resultRelInfo,
 500                                                                   lfirsti(resultRelations),
 501                                                                   rangeTable,
 502                                                                   operation);
 503                                 resultRelInfo++;
 504                                 resultRelations = lnext(resultRelations);
 505                         }
 506                 }
 507                 else
 508                 {
 509                         /*
 510                          * Single result relation identified by
 511                          * parseTree->resultRelation
 512                          */
 513                         numResultRelations = 1;
 514                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 515                         initResultRelInfo(resultRelInfos,
 516                                                           parseTree->resultRelation,
 517                                                           rangeTable,
 518                                                           operation);
 519                 }
 520
 521                 estate->es_result_relations = resultRelInfos;
 522                 estate->es_num_result_relations = numResultRelations;
 523                 /* Initialize to first or only result rel */
 524                 estate->es_result_relation_info = resultRelInfos;
 525         }
 526         else
 527         {
 528                 /*
 529                  * if no result relation, then set state appropriately
 530                  */
 531                 estate->es_result_relations = NULL;
 532                 estate->es_num_result_relations = 0;
 533                 estate->es_result_relation_info = NULL;
 534         }
 535
 536         /*
 537          * Have to lock relations selected for update
 538          */
 539         estate->es_rowMark = NIL;
 540         if (parseTree->rowMarks != NIL)
 541         {
 542                 List       *l;
 543
 544                 foreach(l, parseTree->rowMarks)
 545                 {
 546                         Index           rti = lfirsti(l);
 547                         Oid                     relid = getrelid(rti, rangeTable);
 548                         Relation        relation;
 549                         execRowMark *erm;
 550
 551                         relation = heap_open(relid, RowShareLock);
 552                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 553                         erm->relation = relation;
 554                         erm->rti = rti;
 555                         sprintf(erm->resname, "ctid%u", rti);
 556                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 557                 }
 558         }
 559
 560         /*
 561          * initialize the executor "tuple" table.  We need slots for all the
 562          * plan nodes, plus possibly output slots for the junkfilter(s). At
 563          * this point we aren't sure if we need junkfilters, so just add slots
 564          * for them unconditionally.
 565          */
 566         {
 567                 int                     nSlots = ExecCountSlotsNode(plan);
 568
 569                 if (parseTree->resultRelations != NIL)
 570                         nSlots += length(parseTree->resultRelations);
 571                 else
 572                         nSlots += 1;
 573                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 574         }
 575
 576         /* mark EvalPlanQual not active */
 577         estate->es_origPlan = plan;
 578         estate->es_evalPlanQual = NULL;
 579         estate->es_evTuple = NULL;
 580         estate->es_evTupleNull = NULL;
 581         estate->es_useEvalPlan = false;
 582
 583         /*
 584          * initialize the private state information for all the nodes in the
 585          * query tree.  This opens files, allocates storage and leaves us
 586          * ready to start processing tuples.
 587          */
 588         ExecInitNode(plan, estate, NULL);
 589
 590         /*
 591          * Get the tuple descriptor describing the type of tuples to return.
 592          * (this is especially important if we are creating a relation with
 593          * "retrieve into")
 594          */
 595         tupType = ExecGetTupType(plan);         /* tuple descriptor */
 596
 597         /*
 598          * Initialize the junk filter if needed. SELECT and INSERT queries
 599          * need a filter if there are any junk attrs in the tlist.      UPDATE and
 600          * DELETE always need one, since there's always a junk 'ctid'
 601          * attribute present --- no need to look first.
 602          */
 603         {
 604                 bool            junk_filter_needed = false;
 605                 List       *tlist;
 606
 607                 switch (operation)
 608                 {
 609                         case CMD_SELECT:
 610                         case CMD_INSERT:
 611                                 foreach(tlist, plan->targetlist)
 612                                 {
 613                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 614
 615                                         if (tle->resdom->resjunk)
 616                                         {
 617                                                 junk_filter_needed = true;
 618                                                 break;
 619                                         }
 620                                 }
 621                                 break;
 622                         case CMD_UPDATE:
 623                         case CMD_DELETE:
 624                                 junk_filter_needed = true;
 625                                 break;
 626                         default:
 627                                 break;
 628                 }
 629
 630                 if (junk_filter_needed)
 631                 {
 632                         /*
 633                          * If there are multiple result relations, each one needs its
 634                          * own junk filter.  Note this is only possible for
 635                          * UPDATE/DELETE, so we can't be fooled by some needing a
 636                          * filter and some not.
 637                          */
 638                         if (parseTree->resultRelations != NIL)
 639                         {
 640                                 List       *subplans;
 641                                 ResultRelInfo *resultRelInfo;
 642
 643                                 /* Top plan had better be an Append here. */
 644                                 Assert(IsA(plan, Append));
 645                                 Assert(((Append *) plan)->isTarget);
 646                                 subplans = ((Append *) plan)->appendplans;
 647                                 Assert(length(subplans) == estate->es_num_result_relations);
 648                                 resultRelInfo = estate->es_result_relations;
 649                                 while (subplans != NIL)
 650                                 {
 651                                         Plan       *subplan = (Plan *) lfirst(subplans);
 652                                         JunkFilter *j;
 653
 654                                         j = ExecInitJunkFilter(subplan->targetlist,
 655                                                                                    ExecGetTupType(subplan),
 656                                                           ExecAllocTableSlot(estate->es_tupleTable));
 657                                         resultRelInfo->ri_junkFilter = j;
 658                                         resultRelInfo++;
 659                                         subplans = lnext(subplans);
 660                                 }
 661
 662                                 /*
 663                                  * Set active junkfilter too; at this point ExecInitAppend
 664                                  * has already selected an active result relation...
 665                                  */
 666                                 estate->es_junkFilter =
 667                                         estate->es_result_relation_info->ri_junkFilter;
 668                         }
 669                         else
 670                         {
 671                                 /* Normal case with just one JunkFilter */
 672                                 JunkFilter *j;
 673
 674                                 j = ExecInitJunkFilter(plan->targetlist,
 675                                                                            tupType,
 676                                                           ExecAllocTableSlot(estate->es_tupleTable));
 677                                 estate->es_junkFilter = j;
 678                                 if (estate->es_result_relation_info)
 679                                         estate->es_result_relation_info->ri_junkFilter = j;
 680
 681                                 /* For SELECT, want to return the cleaned tuple type */
 682                                 if (operation == CMD_SELECT)
 683                                         tupType = j->jf_cleanTupType;
 684                         }
 685                 }
 686                 else
 687                         estate->es_junkFilter = NULL;
 688         }
 689
 690         /*
 691          * initialize the "into" relation
 692          */
 693         intoRelationDesc = (Relation) NULL;
 694
 695         if (operation == CMD_SELECT)
 696         {
 697                 if (!parseTree->isPortal)
 698                 {
 699                         /*
 700                          * a select into table --- need to create the "into" table
 701                          */
 702                         if (parseTree->into != NULL)
 703                         {
 704                                 char       *intoName;
 705                                 Oid                     namespaceId;
 706                                 Oid                     intoRelationId;
 707                                 TupleDesc       tupdesc;
 708
 709                                 /*
 710                                  * find namespace to create in, check permissions
 711                                  */
 712                                 intoName = parseTree->into->relname;
 713                                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 714
 715                                 if (!isTempNamespace(namespaceId))
 716                                 {
 717                                         AclResult       aclresult;
 718
 719                                         aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 720                                                                                                           ACL_CREATE);
 721                                         if (aclresult != ACLCHECK_OK)
 722                                                 aclcheck_error(aclresult,
 723                                                                            get_namespace_name(namespaceId));
 724                                 }
 725
 726                                 /*
 727                                  * have to copy tupType to get rid of constraints
 728                                  */
 729                                 tupdesc = CreateTupleDescCopy(tupType);
 730
 731                                 intoRelationId =
 732                                         heap_create_with_catalog(intoName,
 733                                                                                          namespaceId,
 734                                                                                          tupdesc,
 735                                                                                          RELKIND_RELATION,
 736                                                                                          true,
 737                                                                                          allowSystemTableMods);
 738
 739                                 FreeTupleDesc(tupdesc);
 740
 741                                 /*
 742                                  * Advance command counter so that the newly-created
 743                                  * relation's catalog tuples will be visible to heap_open.
 744                                  */
 745                                 CommandCounterIncrement();
 746
 747                                 /*
 748                                  * If necessary, create a TOAST table for the into
 749                                  * relation. Note that AlterTableCreateToastTable ends
 750                                  * with CommandCounterIncrement(), so that the TOAST table
 751                                  * will be visible for insertion.
 752                                  */
 753                                 AlterTableCreateToastTable(intoRelationId, true);
 754
 755                                 intoRelationDesc = heap_open(intoRelationId,
 756                                                                                          AccessExclusiveLock);
 757                         }
 758                 }
 759         }
 760
 761         estate->es_into_relation_descriptor = intoRelationDesc;
 762
 763         return tupType;
 764 }
 765
 766 /*
 767  * Initialize ResultRelInfo data for one result relation
 768  */
 769 static void
 770 initResultRelInfo(ResultRelInfo *resultRelInfo,
 771                                   Index resultRelationIndex,
 772                                   List *rangeTable,
 773                                   CmdType operation)
 774 {
 775         Oid                     resultRelationOid;
 776         Relation        resultRelationDesc;
 777
 778         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 779         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 780
 781         switch (resultRelationDesc->rd_rel->relkind)
 782         {
 783                 case RELKIND_SEQUENCE:
 784                         elog(ERROR, "You can't change sequence relation %s",
 785                                  RelationGetRelationName(resultRelationDesc));
 786                         break;
 787                 case RELKIND_TOASTVALUE:
 788                         elog(ERROR, "You can't change toast relation %s",
 789                                  RelationGetRelationName(resultRelationDesc));
 790                         break;
 791                 case RELKIND_VIEW:
 792                         elog(ERROR, "You can't change view relation %s",
 793                                  RelationGetRelationName(resultRelationDesc));
 794                         break;
 795         }
 796
 797         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 798         resultRelInfo->type = T_ResultRelInfo;
 799         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 800         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 801         resultRelInfo->ri_NumIndices = 0;
 802         resultRelInfo->ri_IndexRelationDescs = NULL;
 803         resultRelInfo->ri_IndexRelationInfo = NULL;
 804         resultRelInfo->ri_TrigDesc = resultRelationDesc->trigdesc;
 805         resultRelInfo->ri_TrigFunctions = NULL;
 806         resultRelInfo->ri_ConstraintExprs = NULL;
 807         resultRelInfo->ri_junkFilter = NULL;
 808
 809         /*
 810          * If there are indices on the result relation, open them and save
 811          * descriptors in the result relation info, so that we can add new
 812          * index entries for the tuples we add/update.  We need not do this
 813          * for a DELETE, however, since deletion doesn't affect indexes.
 814          */
 815         if (resultRelationDesc->rd_rel->relhasindex &&
 816                 operation != CMD_DELETE)
 817                 ExecOpenIndices(resultRelInfo);
 818 }
 819
 820 /* ----------------------------------------------------------------
 821  *              EndPlan
 822  *
 823  *              Cleans up the query plan -- closes files and free up storages
 824  * ----------------------------------------------------------------
 825  */
 826 static void
 827 EndPlan(Plan *plan, EState *estate)
 828 {
 829         ResultRelInfo *resultRelInfo;
 830         int                     i;
 831         List       *l;
 832
 833         /*
 834          * shut down any PlanQual processing we were doing
 835          */
 836         if (estate->es_evalPlanQual != NULL)
 837                 EndEvalPlanQual(estate);
 838
 839         /*
 840          * shut down the node-type-specific query processing
 841          */
 842         ExecEndNode(plan, NULL);
 843
 844         /*
 845          * destroy the executor "tuple" table.
 846          */
 847         ExecDropTupleTable(estate->es_tupleTable, true);
 848         estate->es_tupleTable = NULL;
 849
 850         /*
 851          * close the result relation(s) if any, but hold locks until xact
 852          * commit.      Also clean up junkfilters if present.
 853          */
 854         resultRelInfo = estate->es_result_relations;
 855         for (i = estate->es_num_result_relations; i > 0; i--)
 856         {
 857                 /* Close indices and then the relation itself */
 858                 ExecCloseIndices(resultRelInfo);
 859                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 860                 /* Delete the junkfilter if any */
 861                 if (resultRelInfo->ri_junkFilter != NULL)
 862                         ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
 863                 resultRelInfo++;
 864         }
 865
 866         /*
 867          * close the "into" relation if necessary, again keeping lock
 868          */
 869         if (estate->es_into_relation_descriptor != NULL)
 870                 heap_close(estate->es_into_relation_descriptor, NoLock);
 871
 872         /*
 873          * There might be a junkfilter without a result relation.
 874          */
 875         if (estate->es_num_result_relations == 0 &&
 876                 estate->es_junkFilter != NULL)
 877         {
 878                 ExecFreeJunkFilter(estate->es_junkFilter);
 879                 estate->es_junkFilter = NULL;
 880         }
 881
 882         /*
 883          * close any relations selected FOR UPDATE, again keeping locks
 884          */
 885         foreach(l, estate->es_rowMark)
 886         {
 887                 execRowMark *erm = lfirst(l);
 888
 889                 heap_close(erm->relation, NoLock);
 890         }
 891 }
 892
 893 /* ----------------------------------------------------------------
 894  *              ExecutePlan
 895  *
 896  *              processes the query plan to retrieve 'numberTuples' tuples in the
 897  *              direction specified.
 898  *              Retrieves all tuples if numberTuples is 0
 899  *
 900  *              result is either a slot containing the last tuple in the case
 901  *              of a RETRIEVE or NULL otherwise.
 902  *
 903  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 904  * user can see it
 905  * ----------------------------------------------------------------
 906  */
 907 static TupleTableSlot *
 908 ExecutePlan(EState *estate,
 909                         Plan *plan,
 910                         CmdType operation,
 911                         long numberTuples,
 912                         ScanDirection direction,
 913                         DestReceiver *destfunc)
 914 {
 915         JunkFilter *junkfilter;
 916         TupleTableSlot *slot;
 917         ItemPointer tupleid = NULL;
 918         ItemPointerData tuple_ctid;
 919         long            current_tuple_count;
 920         TupleTableSlot *result;
 921
 922         /*
 923          * initialize local variables
 924          */
 925         slot = NULL;
 926         current_tuple_count = 0;
 927         result = NULL;
 928
 929         /*
 930          * Set the direction.
 931          */
 932         estate->es_direction = direction;
 933
 934         /*
 935          * Loop until we've processed the proper number of tuples from the
 936          * plan.
 937          */
 938
 939         for (;;)
 940         {
 941                 /* Reset the per-output-tuple exprcontext */
 942                 ResetPerTupleExprContext(estate);
 943
 944                 /*
 945                  * Execute the plan and obtain a tuple
 946                  */
 947 lnext:  ;
 948                 if (estate->es_useEvalPlan)
 949                 {
 950                         slot = EvalPlanQualNext(estate);
 951                         if (TupIsNull(slot))
 952                                 slot = ExecProcNode(plan, NULL);
 953                 }
 954                 else
 955                         slot = ExecProcNode(plan, NULL);
 956
 957                 /*
 958                  * if the tuple is null, then we assume there is nothing more to
 959                  * process so we just return null...
 960                  */
 961                 if (TupIsNull(slot))
 962                 {
 963                         result = NULL;
 964                         break;
 965                 }
 966
 967                 /*
 968                  * if we have a junk filter, then project a new tuple with the
 969                  * junk removed.
 970                  *
 971                  * Store this new "clean" tuple in the junkfilter's resultSlot.
 972                  * (Formerly, we stored it back over the "dirty" tuple, which is
 973                  * WRONG because that tuple slot has the wrong descriptor.)
 974                  *
 975                  * Also, extract all the junk information we need.
 976                  */
 977                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
 978                 {
 979                         Datum           datum;
 980                         HeapTuple       newTuple;
 981                         bool            isNull;
 982
 983                         /*
 984                          * extract the 'ctid' junk attribute.
 985                          */
 986                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
 987                         {
 988                                 if (!ExecGetJunkAttribute(junkfilter,
 989                                                                                   slot,
 990                                                                                   "ctid",
 991                                                                                   &datum,
 992                                                                                   &isNull))
 993                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
 994
 995                                 /* shouldn't ever get a null result... */
 996                                 if (isNull)
 997                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
 998
 999                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1000                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1001                                                                                  * ctid!! */
1002                                 tupleid = &tuple_ctid;
1003                         }
1004                         else if (estate->es_rowMark != NIL)
1005                         {
1006                                 List       *l;
1007
1008                 lmark:  ;
1009                                 foreach(l, estate->es_rowMark)
1010                                 {
1011                                         execRowMark *erm = lfirst(l);
1012                                         Buffer          buffer;
1013                                         HeapTupleData tuple;
1014                                         TupleTableSlot *newSlot;
1015                                         int                     test;
1016
1017                                         if (!ExecGetJunkAttribute(junkfilter,
1018                                                                                           slot,
1019                                                                                           erm->resname,
1020                                                                                           &datum,
1021                                                                                           &isNull))
1022                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1023                                                          erm->resname);
1024
1025                                         /* shouldn't ever get a null result... */
1026                                         if (isNull)
1027                                                 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1028                                                          erm->resname);
1029
1030                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1031                                         test = heap_mark4update(erm->relation, &tuple, &buffer);
1032                                         ReleaseBuffer(buffer);
1033                                         switch (test)
1034                                         {
1035                                                 case HeapTupleSelfUpdated:
1036                                                 case HeapTupleMayBeUpdated:
1037                                                         break;
1038
1039                                                 case HeapTupleUpdated:
1040                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1041                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1042                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1043                                                                   (ItemPointer) DatumGetPointer(datum))))
1044                                                         {
1045                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1046                                                                 if (!(TupIsNull(newSlot)))
1047                                                                 {
1048                                                                         slot = newSlot;
1049                                                                         estate->es_useEvalPlan = true;
1050                                                                         goto lmark;
1051                                                                 }
1052                                                         }
1053
1054                                                         /*
1055                                                          * if tuple was deleted or PlanQual failed for
1056                                                          * updated tuple - we must not return this
1057                                                          * tuple!
1058                                                          */
1059                                                         goto lnext;
1060
1061                                                 default:
1062                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1063                                                         return (NULL);
1064                                         }
1065                                 }
1066                         }
1067
1068                         /*
1069                          * Finally create a new "clean" tuple with all junk attributes
1070                          * removed
1071                          */
1072                         newTuple = ExecRemoveJunk(junkfilter, slot);
1073
1074                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1075                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1076                                                                   InvalidBuffer,                /* this tuple has no
1077                                                                                                                  * buffer */
1078                                                                   true);                /* tuple should be pfreed */
1079                 }                                               /* if (junkfilter... */
1080
1081                 /*
1082                  * now that we have a tuple, do the appropriate thing with it..
1083                  * either return it to the user, add it to a relation someplace,
1084                  * delete it from a relation, or modify some of its attributes.
1085                  */
1086
1087                 switch (operation)
1088                 {
1089                         case CMD_SELECT:
1090                                 ExecRetrieve(slot,              /* slot containing tuple */
1091                                                          destfunc,      /* destination's tuple-receiver
1092                                                                                  * obj */
1093                                                          estate);       /* */
1094                                 result = slot;
1095                                 break;
1096
1097                         case CMD_INSERT:
1098                                 ExecAppend(slot, tupleid, estate);
1099                                 result = NULL;
1100                                 break;
1101
1102                         case CMD_DELETE:
1103                                 ExecDelete(slot, tupleid, estate);
1104                                 result = NULL;
1105                                 break;
1106
1107                         case CMD_UPDATE:
1108                                 ExecReplace(slot, tupleid, estate);
1109                                 result = NULL;
1110                                 break;
1111
1112                         default:
1113                                 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1114                                 result = NULL;
1115                                 break;
1116                 }
1117
1118                 /*
1119                  * check our tuple count.. if we've processed the proper number
1120                  * then quit, else loop again and process more tuples..
1121                  */
1122                 current_tuple_count++;
1123                 if (numberTuples == current_tuple_count)
1124                         break;
1125         }
1126
1127         /*
1128          * here, result is either a slot containing a tuple in the case of a
1129          * RETRIEVE or NULL otherwise.
1130          */
1131         return result;
1132 }
1133
1134 /* ----------------------------------------------------------------
1135  *              ExecRetrieve
1136  *
1137  *              RETRIEVEs are easy.. we just pass the tuple to the appropriate
1138  *              print function.  The only complexity is when we do a
1139  *              "retrieve into", in which case we insert the tuple into
1140  *              the appropriate relation (note: this is a newly created relation
1141  *              so we don't need to worry about indices or locks.)
1142  * ----------------------------------------------------------------
1143  */
1144 static void
1145 ExecRetrieve(TupleTableSlot *slot,
1146                          DestReceiver *destfunc,
1147                          EState *estate)
1148 {
1149         HeapTuple       tuple;
1150         TupleDesc       attrtype;
1151
1152         /*
1153          * get the heap tuple out of the tuple table slot
1154          */
1155         tuple = slot->val;
1156         attrtype = slot->ttc_tupleDescriptor;
1157
1158         /*
1159          * insert the tuple into the "into relation"
1160          */
1161         if (estate->es_into_relation_descriptor != NULL)
1162         {
1163                 heap_insert(estate->es_into_relation_descriptor, tuple);
1164                 IncrAppended();
1165         }
1166
1167         /*
1168          * send the tuple to the front end (or the screen)
1169          */
1170         (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1171         IncrRetrieved();
1172         (estate->es_processed)++;
1173 }
1174
1175 /* ----------------------------------------------------------------
1176  *              ExecAppend
1177  *
1178  *              APPENDs are trickier.. we have to insert the tuple into
1179  *              the base relation and insert appropriate tuples into the
1180  *              index relations.
1181  * ----------------------------------------------------------------
1182  */
1183
1184 static void
1185 ExecAppend(TupleTableSlot *slot,
1186                    ItemPointer tupleid,
1187                    EState *estate)
1188 {
1189         HeapTuple       tuple;
1190         ResultRelInfo *resultRelInfo;
1191         Relation        resultRelationDesc;
1192         int                     numIndices;
1193         Oid                     newId;
1194
1195         /*
1196          * get the heap tuple out of the tuple table slot
1197          */
1198         tuple = slot->val;
1199
1200         /*
1201          * get information on the (current) result relation
1202          */
1203         resultRelInfo = estate->es_result_relation_info;
1204         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1205
1206         /* BEFORE ROW INSERT Triggers */
1207         if (resultRelInfo->ri_TrigDesc &&
1208           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1209         {
1210                 HeapTuple       newtuple;
1211
1212                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1213
1214                 if (newtuple == NULL)   /* "do nothing" */
1215                         return;
1216
1217                 if (newtuple != tuple)  /* modified by Trigger(s) */
1218                 {
1219                         /*
1220                          * Insert modified tuple into tuple table slot, replacing the
1221                          * original.  We assume that it was allocated in per-tuple
1222                          * memory context, and therefore will go away by itself. The
1223                          * tuple table slot should not try to clear it.
1224                          */
1225                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1226                         tuple = newtuple;
1227                 }
1228         }
1229
1230         /*
1231          * Check the constraints of the tuple
1232          */
1233         if (resultRelationDesc->rd_att->constr)
1234                 ExecConstraints("ExecAppend", resultRelInfo, slot, estate);
1235
1236         /*
1237          * insert the tuple
1238          */
1239         newId = heap_insert(resultRelationDesc, tuple);
1240
1241         IncrAppended();
1242         (estate->es_processed)++;
1243         estate->es_lastoid = newId;
1244         setLastTid(&(tuple->t_self));
1245
1246         /*
1247          * process indices
1248          *
1249          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1250          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1251          * field.
1252          */
1253         numIndices = resultRelInfo->ri_NumIndices;
1254         if (numIndices > 0)
1255                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1256
1257         /* AFTER ROW INSERT Triggers */
1258         if (resultRelInfo->ri_TrigDesc)
1259                 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1260 }
1261
1262 /* ----------------------------------------------------------------
1263  *              ExecDelete
1264  *
1265  *              DELETE is like append, we delete the tuple and its
1266  *              index tuples.
1267  * ----------------------------------------------------------------
1268  */
1269 static void
1270 ExecDelete(TupleTableSlot *slot,
1271                    ItemPointer tupleid,
1272                    EState *estate)
1273 {
1274         ResultRelInfo *resultRelInfo;
1275         Relation        resultRelationDesc;
1276         ItemPointerData ctid;
1277         int                     result;
1278
1279         /*
1280          * get information on the (current) result relation
1281          */
1282         resultRelInfo = estate->es_result_relation_info;
1283         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1284
1285         /* BEFORE ROW DELETE Triggers */
1286         if (resultRelInfo->ri_TrigDesc &&
1287           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1288         {
1289                 bool            dodelete;
1290
1291                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
1292
1293                 if (!dodelete)                  /* "do nothing" */
1294                         return;
1295         }
1296
1297         /*
1298          * delete the tuple
1299          */
1300 ldelete:;
1301         result = heap_delete(resultRelationDesc, tupleid, &ctid);
1302         switch (result)
1303         {
1304                 case HeapTupleSelfUpdated:
1305                         return;
1306
1307                 case HeapTupleMayBeUpdated:
1308                         break;
1309
1310                 case HeapTupleUpdated:
1311                         if (XactIsoLevel == XACT_SERIALIZABLE)
1312                                 elog(ERROR, "Can't serialize access due to concurrent update");
1313                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1314                         {
1315                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1316                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1317
1318                                 if (!TupIsNull(epqslot))
1319                                 {
1320                                         *tupleid = ctid;
1321                                         goto ldelete;
1322                                 }
1323                         }
1324                         /* tuple already deleted; nothing to do */
1325                         return;
1326
1327                 default:
1328                         elog(ERROR, "Unknown status %u from heap_delete", result);
1329                         return;
1330         }
1331
1332         IncrDeleted();
1333         (estate->es_processed)++;
1334
1335         /*
1336          * Note: Normally one would think that we have to delete index tuples
1337          * associated with the heap tuple now..
1338          *
1339          * ... but in POSTGRES, we have no need to do this because the vacuum
1340          * daemon automatically opens an index scan and deletes index tuples
1341          * when it finds deleted heap tuples. -cim 9/27/89
1342          */
1343
1344         /* AFTER ROW DELETE Triggers */
1345         if (resultRelInfo->ri_TrigDesc)
1346                 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1347 }
1348
1349 /* ----------------------------------------------------------------
1350  *              ExecReplace
1351  *
1352  *              note: we can't run replace queries with transactions
1353  *              off because replaces are actually appends and our
1354  *              scan will mistakenly loop forever, replacing the tuple
1355  *              it just appended..      This should be fixed but until it
1356  *              is, we don't want to get stuck in an infinite loop
1357  *              which corrupts your database..
1358  * ----------------------------------------------------------------
1359  */
1360 static void
1361 ExecReplace(TupleTableSlot *slot,
1362                         ItemPointer tupleid,
1363                         EState *estate)
1364 {
1365         HeapTuple       tuple;
1366         ResultRelInfo *resultRelInfo;
1367         Relation        resultRelationDesc;
1368         ItemPointerData ctid;
1369         int                     result;
1370         int                     numIndices;
1371
1372         /*
1373          * abort the operation if not running transactions
1374          */
1375         if (IsBootstrapProcessingMode())
1376         {
1377                 elog(WARNING, "ExecReplace: replace can't run without transactions");
1378                 return;
1379         }
1380
1381         /*
1382          * get the heap tuple out of the tuple table slot
1383          */
1384         tuple = slot->val;
1385
1386         /*
1387          * get information on the (current) result relation
1388          */
1389         resultRelInfo = estate->es_result_relation_info;
1390         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1391
1392         /* BEFORE ROW UPDATE Triggers */
1393         if (resultRelInfo->ri_TrigDesc &&
1394           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1395         {
1396                 HeapTuple       newtuple;
1397
1398                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1399                                                                                 tupleid, tuple);
1400
1401                 if (newtuple == NULL)   /* "do nothing" */
1402                         return;
1403
1404                 if (newtuple != tuple)  /* modified by Trigger(s) */
1405                 {
1406                         /*
1407                          * Insert modified tuple into tuple table slot, replacing the
1408                          * original.  We assume that it was allocated in per-tuple
1409                          * memory context, and therefore will go away by itself. The
1410                          * tuple table slot should not try to clear it.
1411                          */
1412                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1413                         tuple = newtuple;
1414                 }
1415         }
1416
1417         /*
1418          * Check the constraints of the tuple
1419          *
1420          * If we generate a new candidate tuple after EvalPlanQual testing, we
1421          * must loop back here and recheck constraints.  (We don't need to
1422          * redo triggers, however.      If there are any BEFORE triggers then
1423          * trigger.c will have done mark4update to lock the correct tuple, so
1424          * there's no need to do them again.)
1425          */
1426 lreplace:;
1427         if (resultRelationDesc->rd_att->constr)
1428                 ExecConstraints("ExecReplace", resultRelInfo, slot, estate);
1429
1430         /*
1431          * replace the heap tuple
1432          */
1433         result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
1434         switch (result)
1435         {
1436                 case HeapTupleSelfUpdated:
1437                         return;
1438
1439                 case HeapTupleMayBeUpdated:
1440                         break;
1441
1442                 case HeapTupleUpdated:
1443                         if (XactIsoLevel == XACT_SERIALIZABLE)
1444                                 elog(ERROR, "Can't serialize access due to concurrent update");
1445                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1446                         {
1447                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1448                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1449
1450                                 if (!TupIsNull(epqslot))
1451                                 {
1452                                         *tupleid = ctid;
1453                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1454                                         slot = ExecStoreTuple(tuple,
1455                                                                         estate->es_junkFilter->jf_resultSlot,
1456                                                                                   InvalidBuffer, true);
1457                                         goto lreplace;
1458                                 }
1459                         }
1460                         /* tuple already deleted; nothing to do */
1461                         return;
1462
1463                 default:
1464                         elog(ERROR, "Unknown status %u from heap_update", result);
1465                         return;
1466         }
1467
1468         IncrReplaced();
1469         (estate->es_processed)++;
1470
1471         /*
1472          * Note: instead of having to update the old index tuples associated
1473          * with the heap tuple, all we do is form and insert new index tuples.
1474          * This is because replaces are actually deletes and inserts and index
1475          * tuple deletion is done automagically by the vacuum daemon. All we
1476          * do is insert new index tuples.  -cim 9/27/89
1477          */
1478
1479         /*
1480          * process indices
1481          *
1482          * heap_update updates a tuple in the base relation by invalidating it
1483          * and then appending a new tuple to the relation.      As a side effect,
1484          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1485          * field.  So we now insert index tuples using the new tupleid stored
1486          * there.
1487          */
1488
1489         numIndices = resultRelInfo->ri_NumIndices;
1490         if (numIndices > 0)
1491                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
1492
1493         /* AFTER ROW UPDATE Triggers */
1494         if (resultRelInfo->ri_TrigDesc)
1495                 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1496 }
1497
1498 static char *
1499 ExecRelCheck(ResultRelInfo *resultRelInfo,
1500                          TupleTableSlot *slot, EState *estate)
1501 {
1502         Relation        rel = resultRelInfo->ri_RelationDesc;
1503         int                     ncheck = rel->rd_att->constr->num_check;
1504         ConstrCheck *check = rel->rd_att->constr->check;
1505         ExprContext *econtext;
1506         MemoryContext oldContext;
1507         List       *qual;
1508         int                     i;
1509
1510         /*
1511          * If first time through for this result relation, build expression
1512          * nodetrees for rel's constraint expressions.  Keep them in the
1513          * per-query memory context so they'll survive throughout the query.
1514          */
1515         if (resultRelInfo->ri_ConstraintExprs == NULL)
1516         {
1517                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1518                 resultRelInfo->ri_ConstraintExprs =
1519                         (List **) palloc(ncheck * sizeof(List *));
1520                 for (i = 0; i < ncheck; i++)
1521                 {
1522                         qual = (List *) stringToNode(check[i].ccbin);
1523                         resultRelInfo->ri_ConstraintExprs[i] = qual;
1524                 }
1525                 MemoryContextSwitchTo(oldContext);
1526         }
1527
1528         /*
1529          * We will use the EState's per-tuple context for evaluating
1530          * constraint expressions (creating it if it's not already there).
1531          */
1532         econtext = GetPerTupleExprContext(estate);
1533
1534         /* Arrange for econtext's scan tuple to be the tuple under test */
1535         econtext->ecxt_scantuple = slot;
1536
1537         /* And evaluate the constraints */
1538         for (i = 0; i < ncheck; i++)
1539         {
1540                 qual = resultRelInfo->ri_ConstraintExprs[i];
1541
1542                 /*
1543                  * NOTE: SQL92 specifies that a NULL result from a constraint
1544                  * expression is not to be treated as a failure.  Therefore, tell
1545                  * ExecQual to return TRUE for NULL.
1546                  */
1547                 if (!ExecQual(qual, econtext, true))
1548                         return check[i].ccname;
1549         }
1550
1551         /* NULL result means no error */
1552         return (char *) NULL;
1553 }
1554
1555 void
1556 ExecConstraints(char *caller, ResultRelInfo *resultRelInfo,
1557                                 TupleTableSlot *slot, EState *estate)
1558 {
1559         Relation        rel = resultRelInfo->ri_RelationDesc;
1560         HeapTuple       tuple = slot->val;
1561         TupleConstr *constr = rel->rd_att->constr;
1562
1563         Assert(constr);
1564
1565         if (constr->has_not_null)
1566         {
1567                 int                     natts = rel->rd_att->natts;
1568                 int                     attrChk;
1569
1570                 for (attrChk = 1; attrChk <= natts; attrChk++)
1571                 {
1572                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1573                                 heap_attisnull(tuple, attrChk))
1574                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1575                                          caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1576                 }
1577         }
1578
1579         if (constr->num_check > 0)
1580         {
1581                 char       *failed;
1582
1583                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1584                         elog(ERROR, "%s: rejected due to CHECK constraint %s",
1585                                  caller, failed);
1586         }
1587 }
1588
1589 /*
1590  * Check a modified tuple to see if we want to process its updated version
1591  * under READ COMMITTED rules.
1592  *
1593  * See backend/executor/README for some info about how this works.
1594  */
1595 TupleTableSlot *
1596 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1597 {
1598         evalPlanQual *epq;
1599         EState     *epqstate;
1600         Relation        relation;
1601         HeapTupleData tuple;
1602         HeapTuple       copyTuple = NULL;
1603         int                     rtsize;
1604         bool            endNode;
1605
1606         Assert(rti != 0);
1607
1608         /*
1609          * find relation containing target tuple
1610          */
1611         if (estate->es_result_relation_info != NULL &&
1612                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1613                 relation = estate->es_result_relation_info->ri_RelationDesc;
1614         else
1615         {
1616                 List       *l;
1617
1618                 relation = NULL;
1619                 foreach(l, estate->es_rowMark)
1620                 {
1621                         if (((execRowMark *) lfirst(l))->rti == rti)
1622                         {
1623                                 relation = ((execRowMark *) lfirst(l))->relation;
1624                                 break;
1625                         }
1626                 }
1627                 if (relation == NULL)
1628                         elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1629         }
1630
1631         /*
1632          * fetch tid tuple
1633          *
1634          * Loop here to deal with updated or busy tuples
1635          */
1636         tuple.t_self = *tid;
1637         for (;;)
1638         {
1639                 Buffer          buffer;
1640
1641                 heap_fetch(relation, SnapshotDirty, &tuple, &buffer, NULL);
1642                 if (tuple.t_data != NULL)
1643                 {
1644                         TransactionId xwait = SnapshotDirty->xmax;
1645
1646                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1647                                 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1648
1649                         /*
1650                          * If tuple is being updated by other transaction then we have
1651                          * to wait for its commit/abort.
1652                          */
1653                         if (TransactionIdIsValid(xwait))
1654                         {
1655                                 ReleaseBuffer(buffer);
1656                                 XactLockTableWait(xwait);
1657                                 continue;
1658                         }
1659
1660                         /*
1661                          * We got tuple - now copy it for use by recheck query.
1662                          */
1663                         copyTuple = heap_copytuple(&tuple);
1664                         ReleaseBuffer(buffer);
1665                         break;
1666                 }
1667
1668                 /*
1669                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1670                  * Note that it's possible to get invalid SnapshotDirty->tid if
1671                  * tuple updated by this transaction. Have we to check this ?
1672                  */
1673                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1674                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1675                 {
1676                         /* updated, so look at the updated copy */
1677                         tuple.t_self = SnapshotDirty->tid;
1678                         continue;
1679                 }
1680
1681                 /*
1682                  * Deleted or updated by this transaction; forget it.
1683                  */
1684                 return NULL;
1685         }
1686
1687         /*
1688          * For UPDATE/DELETE we have to return tid of actual row we're
1689          * executing PQ for.
1690          */
1691         *tid = tuple.t_self;
1692
1693         /*
1694          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1695          */
1696         epq = (evalPlanQual *) estate->es_evalPlanQual;
1697         rtsize = length(estate->es_range_table);
1698         endNode = true;
1699
1700         if (epq != NULL && epq->rti == 0)
1701         {
1702                 /* Top PQ stack entry is idle, so re-use it */
1703                 Assert(!(estate->es_useEvalPlan) &&
1704                            epq->estate.es_evalPlanQual == NULL);
1705                 epq->rti = rti;
1706                 endNode = false;
1707         }
1708
1709         /*
1710          * If this is request for another RTE - Ra, - then we have to check
1711          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1712          * updated again and we have to re-start old execution for Ra and
1713          * forget all what we done after Ra was suspended. Cool? -:))
1714          */
1715         if (epq != NULL && epq->rti != rti &&
1716                 epq->estate.es_evTuple[rti - 1] != NULL)
1717         {
1718                 do
1719                 {
1720                         evalPlanQual *oldepq;
1721
1722                         /* pop previous PlanQual from the stack */
1723                         epqstate = &(epq->estate);
1724                         oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1725                         Assert(oldepq->rti != 0);
1726                         /* stop execution */
1727                         ExecEndNode(epq->plan, NULL);
1728                         ExecDropTupleTable(epqstate->es_tupleTable, true);
1729                         epqstate->es_tupleTable = NULL;
1730                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1731                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1732                         /* push current PQ to freePQ stack */
1733                         oldepq->free = epq;
1734                         epq = oldepq;
1735                         estate->es_evalPlanQual = (Pointer) epq;
1736                 } while (epq->rti != rti);
1737         }
1738
1739         /*
1740          * If we are requested for another RTE then we have to suspend
1741          * execution of current PlanQual and start execution for new one.
1742          */
1743         if (epq == NULL || epq->rti != rti)
1744         {
1745                 /* try to reuse plan used previously */
1746                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1747
1748                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1749                 {
1750                         newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1751                         newepq->free = NULL;
1752
1753                         /*
1754                          * Each stack level has its own copy of the plan tree.  This
1755                          * is wasteful, but necessary as long as plan nodes point to
1756                          * exec state nodes rather than vice versa.  Note that
1757                          * copyfuncs.c doesn't attempt to copy the exec state nodes,
1758                          * which is a good thing in this situation.
1759                          */
1760                         newepq->plan = copyObject(estate->es_origPlan);
1761
1762                         /*
1763                          * Init stack level's EState.  We share top level's copy of
1764                          * es_result_relations array and other non-changing status. We
1765                          * need our own tupletable, es_param_exec_vals, and other
1766                          * changeable state.
1767                          */
1768                         epqstate = &(newepq->estate);
1769                         memcpy(epqstate, estate, sizeof(EState));
1770                         epqstate->es_direction = ForwardScanDirection;
1771                         if (estate->es_origPlan->nParamExec > 0)
1772                                 epqstate->es_param_exec_vals = (ParamExecData *)
1773                                         palloc(estate->es_origPlan->nParamExec *
1774                                                    sizeof(ParamExecData));
1775                         epqstate->es_tupleTable = NULL;
1776                         epqstate->es_per_tuple_exprcontext = NULL;
1777
1778                         /*
1779                          * Each epqstate must have its own es_evTupleNull state, but
1780                          * all the stack entries share es_evTuple state.  This allows
1781                          * sub-rechecks to inherit the value being examined by an
1782                          * outer recheck.
1783                          */
1784                         epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
1785                         if (epq == NULL)
1786                         {
1787                                 /* first PQ stack entry */
1788                                 epqstate->es_evTuple = (HeapTuple *)
1789                                         palloc(rtsize * sizeof(HeapTuple));
1790                                 memset(epqstate->es_evTuple, 0, rtsize * sizeof(HeapTuple));
1791                         }
1792                         else
1793                         {
1794                                 /* later stack entries share the same storage */
1795                                 epqstate->es_evTuple = epq->estate.es_evTuple;
1796                         }
1797                 }
1798                 else
1799                 {
1800                         /* recycle previously used EState */
1801                         epqstate = &(newepq->estate);
1802                 }
1803                 /* push current PQ to the stack */
1804                 epqstate->es_evalPlanQual = (Pointer) epq;
1805                 epq = newepq;
1806                 estate->es_evalPlanQual = (Pointer) epq;
1807                 epq->rti = rti;
1808                 endNode = false;
1809         }
1810
1811         Assert(epq->rti == rti);
1812         epqstate = &(epq->estate);
1813
1814         /*
1815          * Ok - we're requested for the same RTE.  Unfortunately we still have
1816          * to end and restart execution of the plan, because ExecReScan
1817          * wouldn't ensure that upper plan nodes would reset themselves.  We
1818          * could make that work if insertion of the target tuple were
1819          * integrated with the Param mechanism somehow, so that the upper plan
1820          * nodes know that their children's outputs have changed.
1821          */
1822         if (endNode)
1823         {
1824                 /* stop execution */
1825                 ExecEndNode(epq->plan, NULL);
1826                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1827                 epqstate->es_tupleTable = NULL;
1828         }
1829
1830         /*
1831          * free old RTE' tuple, if any, and store target tuple where
1832          * relation's scan node will see it
1833          */
1834         if (epqstate->es_evTuple[rti - 1] != NULL)
1835                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1836         epqstate->es_evTuple[rti - 1] = copyTuple;
1837
1838         /*
1839          * Initialize for new recheck query; be careful to copy down state
1840          * that might have changed in top EState.
1841          */
1842         epqstate->es_result_relation_info = estate->es_result_relation_info;
1843         epqstate->es_junkFilter = estate->es_junkFilter;
1844         if (estate->es_origPlan->nParamExec > 0)
1845                 memset(epqstate->es_param_exec_vals, 0,
1846                            estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1847         memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
1848         epqstate->es_useEvalPlan = false;
1849         Assert(epqstate->es_tupleTable == NULL);
1850         epqstate->es_tupleTable =
1851                 ExecCreateTupleTable(estate->es_tupleTable->size);
1852
1853         ExecInitNode(epq->plan, epqstate, NULL);
1854
1855         return EvalPlanQualNext(estate);
1856 }
1857
1858 static TupleTableSlot *
1859 EvalPlanQualNext(EState *estate)
1860 {
1861         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1862         EState     *epqstate = &(epq->estate);
1863         evalPlanQual *oldepq;
1864         TupleTableSlot *slot;
1865
1866         Assert(epq->rti != 0);
1867
1868 lpqnext:;
1869         slot = ExecProcNode(epq->plan, NULL);
1870
1871         /*
1872          * No more tuples for this PQ. Continue previous one.
1873          */
1874         if (TupIsNull(slot))
1875         {
1876                 /* stop execution */
1877                 ExecEndNode(epq->plan, NULL);
1878                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1879                 epqstate->es_tupleTable = NULL;
1880                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1881                 epqstate->es_evTuple[epq->rti - 1] = NULL;
1882                 /* pop old PQ from the stack */
1883                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1884                 if (oldepq == (evalPlanQual *) NULL)
1885                 {
1886                         epq->rti = 0;           /* this is the first (oldest) */
1887                         estate->es_useEvalPlan = false;         /* PQ - mark as free and          */
1888                         return (NULL);          /* continue Query execution   */
1889                 }
1890                 Assert(oldepq->rti != 0);
1891                 /* push current PQ to freePQ stack */
1892                 oldepq->free = epq;
1893                 epq = oldepq;
1894                 epqstate = &(epq->estate);
1895                 estate->es_evalPlanQual = (Pointer) epq;
1896                 goto lpqnext;
1897         }
1898
1899         return (slot);
1900 }
1901
1902 static void
1903 EndEvalPlanQual(EState *estate)
1904 {
1905         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1906         EState     *epqstate = &(epq->estate);
1907         evalPlanQual *oldepq;
1908
1909         if (epq->rti == 0)                      /* plans already shutdowned */
1910         {
1911                 Assert(epq->estate.es_evalPlanQual == NULL);
1912                 return;
1913         }
1914
1915         for (;;)
1916         {
1917                 /* stop execution */
1918                 ExecEndNode(epq->plan, NULL);
1919                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1920                 epqstate->es_tupleTable = NULL;
1921                 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1922                 {
1923                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1924                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1925                 }
1926                 /* pop old PQ from the stack */
1927                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1928                 if (oldepq == (evalPlanQual *) NULL)
1929                 {
1930                         epq->rti = 0;           /* this is the first (oldest) */
1931                         estate->es_useEvalPlan = false;         /* PQ - mark as free */
1932                         break;
1933                 }
1934                 Assert(oldepq->rti != 0);
1935                 /* push current PQ to freePQ stack */
1936                 oldepq->free = epq;
1937                 epq = oldepq;
1938                 epqstate = &(epq->estate);
1939                 estate->es_evalPlanQual = (Pointer) epq;
1940         }
1941 }