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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 1.160 2002/04/27 21:24:34 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                                                                                          false,
 737                                                                                          true,
 738                                                                                          allowSystemTableMods);
 739
 740                                 FreeTupleDesc(tupdesc);
 741
 742                                 /*
 743                                  * Advance command counter so that the newly-created
 744                                  * relation's catalog tuples will be visible to heap_open.
 745                                  */
 746                                 CommandCounterIncrement();
 747
 748                                 /*
 749                                  * If necessary, create a TOAST table for the into
 750                                  * relation. Note that AlterTableCreateToastTable ends
 751                                  * with CommandCounterIncrement(), so that the TOAST table
 752                                  * will be visible for insertion.
 753                                  */
 754                                 AlterTableCreateToastTable(intoRelationId, true);
 755
 756                                 intoRelationDesc = heap_open(intoRelationId,
 757                                                                                          AccessExclusiveLock);
 758                         }
 759                 }
 760         }
 761
 762         estate->es_into_relation_descriptor = intoRelationDesc;
 763
 764         return tupType;
 765 }
 766
 767 /*
 768  * Initialize ResultRelInfo data for one result relation
 769  */
 770 static void
 771 initResultRelInfo(ResultRelInfo *resultRelInfo,
 772                                   Index resultRelationIndex,
 773                                   List *rangeTable,
 774                                   CmdType operation)
 775 {
 776         Oid                     resultRelationOid;
 777         Relation        resultRelationDesc;
 778
 779         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 780         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 781
 782         switch (resultRelationDesc->rd_rel->relkind)
 783         {
 784                 case RELKIND_SEQUENCE:
 785                         elog(ERROR, "You can't change sequence relation %s",
 786                                  RelationGetRelationName(resultRelationDesc));
 787                         break;
 788                 case RELKIND_TOASTVALUE:
 789                         elog(ERROR, "You can't change toast relation %s",
 790                                  RelationGetRelationName(resultRelationDesc));
 791                         break;
 792                 case RELKIND_VIEW:
 793                         elog(ERROR, "You can't change view relation %s",
 794                                  RelationGetRelationName(resultRelationDesc));
 795                         break;
 796         }
 797
 798         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 799         resultRelInfo->type = T_ResultRelInfo;
 800         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 801         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 802         resultRelInfo->ri_NumIndices = 0;
 803         resultRelInfo->ri_IndexRelationDescs = NULL;
 804         resultRelInfo->ri_IndexRelationInfo = NULL;
 805         resultRelInfo->ri_TrigDesc = resultRelationDesc->trigdesc;
 806         resultRelInfo->ri_TrigFunctions = NULL;
 807         resultRelInfo->ri_ConstraintExprs = NULL;
 808         resultRelInfo->ri_junkFilter = NULL;
 809
 810         /*
 811          * If there are indices on the result relation, open them and save
 812          * descriptors in the result relation info, so that we can add new
 813          * index entries for the tuples we add/update.  We need not do this
 814          * for a DELETE, however, since deletion doesn't affect indexes.
 815          */
 816         if (resultRelationDesc->rd_rel->relhasindex &&
 817                 operation != CMD_DELETE)
 818                 ExecOpenIndices(resultRelInfo);
 819 }
 820
 821 /* ----------------------------------------------------------------
 822  *              EndPlan
 823  *
 824  *              Cleans up the query plan -- closes files and free up storages
 825  * ----------------------------------------------------------------
 826  */
 827 static void
 828 EndPlan(Plan *plan, EState *estate)
 829 {
 830         ResultRelInfo *resultRelInfo;
 831         int                     i;
 832         List       *l;
 833
 834         /*
 835          * shut down any PlanQual processing we were doing
 836          */
 837         if (estate->es_evalPlanQual != NULL)
 838                 EndEvalPlanQual(estate);
 839
 840         /*
 841          * shut down the node-type-specific query processing
 842          */
 843         ExecEndNode(plan, NULL);
 844
 845         /*
 846          * destroy the executor "tuple" table.
 847          */
 848         ExecDropTupleTable(estate->es_tupleTable, true);
 849         estate->es_tupleTable = NULL;
 850
 851         /*
 852          * close the result relation(s) if any, but hold locks until xact
 853          * commit.      Also clean up junkfilters if present.
 854          */
 855         resultRelInfo = estate->es_result_relations;
 856         for (i = estate->es_num_result_relations; i > 0; i--)
 857         {
 858                 /* Close indices and then the relation itself */
 859                 ExecCloseIndices(resultRelInfo);
 860                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 861                 /* Delete the junkfilter if any */
 862                 if (resultRelInfo->ri_junkFilter != NULL)
 863                         ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
 864                 resultRelInfo++;
 865         }
 866
 867         /*
 868          * close the "into" relation if necessary, again keeping lock
 869          */
 870         if (estate->es_into_relation_descriptor != NULL)
 871                 heap_close(estate->es_into_relation_descriptor, NoLock);
 872
 873         /*
 874          * There might be a junkfilter without a result relation.
 875          */
 876         if (estate->es_num_result_relations == 0 &&
 877                 estate->es_junkFilter != NULL)
 878         {
 879                 ExecFreeJunkFilter(estate->es_junkFilter);
 880                 estate->es_junkFilter = NULL;
 881         }
 882
 883         /*
 884          * close any relations selected FOR UPDATE, again keeping locks
 885          */
 886         foreach(l, estate->es_rowMark)
 887         {
 888                 execRowMark *erm = lfirst(l);
 889
 890                 heap_close(erm->relation, NoLock);
 891         }
 892 }
 893
 894 /* ----------------------------------------------------------------
 895  *              ExecutePlan
 896  *
 897  *              processes the query plan to retrieve 'numberTuples' tuples in the
 898  *              direction specified.
 899  *              Retrieves all tuples if numberTuples is 0
 900  *
 901  *              result is either a slot containing the last tuple in the case
 902  *              of a RETRIEVE or NULL otherwise.
 903  *
 904  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 905  * user can see it
 906  * ----------------------------------------------------------------
 907  */
 908 static TupleTableSlot *
 909 ExecutePlan(EState *estate,
 910                         Plan *plan,
 911                         CmdType operation,
 912                         long numberTuples,
 913                         ScanDirection direction,
 914                         DestReceiver *destfunc)
 915 {
 916         JunkFilter *junkfilter;
 917         TupleTableSlot *slot;
 918         ItemPointer tupleid = NULL;
 919         ItemPointerData tuple_ctid;
 920         long            current_tuple_count;
 921         TupleTableSlot *result;
 922
 923         /*
 924          * initialize local variables
 925          */
 926         slot = NULL;
 927         current_tuple_count = 0;
 928         result = NULL;
 929
 930         /*
 931          * Set the direction.
 932          */
 933         estate->es_direction = direction;
 934
 935         /*
 936          * Loop until we've processed the proper number of tuples from the
 937          * plan.
 938          */
 939
 940         for (;;)
 941         {
 942                 /* Reset the per-output-tuple exprcontext */
 943                 ResetPerTupleExprContext(estate);
 944
 945                 /*
 946                  * Execute the plan and obtain a tuple
 947                  */
 948 lnext:  ;
 949                 if (estate->es_useEvalPlan)
 950                 {
 951                         slot = EvalPlanQualNext(estate);
 952                         if (TupIsNull(slot))
 953                                 slot = ExecProcNode(plan, NULL);
 954                 }
 955                 else
 956                         slot = ExecProcNode(plan, NULL);
 957
 958                 /*
 959                  * if the tuple is null, then we assume there is nothing more to
 960                  * process so we just return null...
 961                  */
 962                 if (TupIsNull(slot))
 963                 {
 964                         result = NULL;
 965                         break;
 966                 }
 967
 968                 /*
 969                  * if we have a junk filter, then project a new tuple with the
 970                  * junk removed.
 971                  *
 972                  * Store this new "clean" tuple in the junkfilter's resultSlot.
 973                  * (Formerly, we stored it back over the "dirty" tuple, which is
 974                  * WRONG because that tuple slot has the wrong descriptor.)
 975                  *
 976                  * Also, extract all the junk information we need.
 977                  */
 978                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
 979                 {
 980                         Datum           datum;
 981                         HeapTuple       newTuple;
 982                         bool            isNull;
 983
 984                         /*
 985                          * extract the 'ctid' junk attribute.
 986                          */
 987                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
 988                         {
 989                                 if (!ExecGetJunkAttribute(junkfilter,
 990                                                                                   slot,
 991                                                                                   "ctid",
 992                                                                                   &datum,
 993                                                                                   &isNull))
 994                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
 995
 996                                 /* shouldn't ever get a null result... */
 997                                 if (isNull)
 998                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
 999
1000                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1001                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1002                                                                                  * ctid!! */
1003                                 tupleid = &tuple_ctid;
1004                         }
1005                         else if (estate->es_rowMark != NIL)
1006                         {
1007                                 List       *l;
1008
1009                 lmark:  ;
1010                                 foreach(l, estate->es_rowMark)
1011                                 {
1012                                         execRowMark *erm = lfirst(l);
1013                                         Buffer          buffer;
1014                                         HeapTupleData tuple;
1015                                         TupleTableSlot *newSlot;
1016                                         int                     test;
1017
1018                                         if (!ExecGetJunkAttribute(junkfilter,
1019                                                                                           slot,
1020                                                                                           erm->resname,
1021                                                                                           &datum,
1022                                                                                           &isNull))
1023                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1024                                                          erm->resname);
1025
1026                                         /* shouldn't ever get a null result... */
1027                                         if (isNull)
1028                                                 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1029                                                          erm->resname);
1030
1031                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1032                                         test = heap_mark4update(erm->relation, &tuple, &buffer);
1033                                         ReleaseBuffer(buffer);
1034                                         switch (test)
1035                                         {
1036                                                 case HeapTupleSelfUpdated:
1037                                                 case HeapTupleMayBeUpdated:
1038                                                         break;
1039
1040                                                 case HeapTupleUpdated:
1041                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1042                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1043                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1044                                                                   (ItemPointer) DatumGetPointer(datum))))
1045                                                         {
1046                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1047                                                                 if (!(TupIsNull(newSlot)))
1048                                                                 {
1049                                                                         slot = newSlot;
1050                                                                         estate->es_useEvalPlan = true;
1051                                                                         goto lmark;
1052                                                                 }
1053                                                         }
1054
1055                                                         /*
1056                                                          * if tuple was deleted or PlanQual failed for
1057                                                          * updated tuple - we must not return this
1058                                                          * tuple!
1059                                                          */
1060                                                         goto lnext;
1061
1062                                                 default:
1063                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1064                                                         return (NULL);
1065                                         }
1066                                 }
1067                         }
1068
1069                         /*
1070                          * Finally create a new "clean" tuple with all junk attributes
1071                          * removed
1072                          */
1073                         newTuple = ExecRemoveJunk(junkfilter, slot);
1074
1075                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1076                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1077                                                                   InvalidBuffer,                /* this tuple has no
1078                                                                                                                  * buffer */
1079                                                                   true);                /* tuple should be pfreed */
1080                 }                                               /* if (junkfilter... */
1081
1082                 /*
1083                  * now that we have a tuple, do the appropriate thing with it..
1084                  * either return it to the user, add it to a relation someplace,
1085                  * delete it from a relation, or modify some of its attributes.
1086                  */
1087
1088                 switch (operation)
1089                 {
1090                         case CMD_SELECT:
1091                                 ExecRetrieve(slot,              /* slot containing tuple */
1092                                                          destfunc,      /* destination's tuple-receiver
1093                                                                                  * obj */
1094                                                          estate);       /* */
1095                                 result = slot;
1096                                 break;
1097
1098                         case CMD_INSERT:
1099                                 ExecAppend(slot, tupleid, estate);
1100                                 result = NULL;
1101                                 break;
1102
1103                         case CMD_DELETE:
1104                                 ExecDelete(slot, tupleid, estate);
1105                                 result = NULL;
1106                                 break;
1107
1108                         case CMD_UPDATE:
1109                                 ExecReplace(slot, tupleid, estate);
1110                                 result = NULL;
1111                                 break;
1112
1113                         default:
1114                                 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1115                                 result = NULL;
1116                                 break;
1117                 }
1118
1119                 /*
1120                  * check our tuple count.. if we've processed the proper number
1121                  * then quit, else loop again and process more tuples..
1122                  */
1123                 current_tuple_count++;
1124                 if (numberTuples == current_tuple_count)
1125                         break;
1126         }
1127
1128         /*
1129          * here, result is either a slot containing a tuple in the case of a
1130          * RETRIEVE or NULL otherwise.
1131          */
1132         return result;
1133 }
1134
1135 /* ----------------------------------------------------------------
1136  *              ExecRetrieve
1137  *
1138  *              RETRIEVEs are easy.. we just pass the tuple to the appropriate
1139  *              print function.  The only complexity is when we do a
1140  *              "retrieve into", in which case we insert the tuple into
1141  *              the appropriate relation (note: this is a newly created relation
1142  *              so we don't need to worry about indices or locks.)
1143  * ----------------------------------------------------------------
1144  */
1145 static void
1146 ExecRetrieve(TupleTableSlot *slot,
1147                          DestReceiver *destfunc,
1148                          EState *estate)
1149 {
1150         HeapTuple       tuple;
1151         TupleDesc       attrtype;
1152
1153         /*
1154          * get the heap tuple out of the tuple table slot
1155          */
1156         tuple = slot->val;
1157         attrtype = slot->ttc_tupleDescriptor;
1158
1159         /*
1160          * insert the tuple into the "into relation"
1161          */
1162         if (estate->es_into_relation_descriptor != NULL)
1163         {
1164                 heap_insert(estate->es_into_relation_descriptor, tuple);
1165                 IncrAppended();
1166         }
1167
1168         /*
1169          * send the tuple to the front end (or the screen)
1170          */
1171         (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1172         IncrRetrieved();
1173         (estate->es_processed)++;
1174 }
1175
1176 /* ----------------------------------------------------------------
1177  *              ExecAppend
1178  *
1179  *              APPENDs are trickier.. we have to insert the tuple into
1180  *              the base relation and insert appropriate tuples into the
1181  *              index relations.
1182  * ----------------------------------------------------------------
1183  */
1184
1185 static void
1186 ExecAppend(TupleTableSlot *slot,
1187                    ItemPointer tupleid,
1188                    EState *estate)
1189 {
1190         HeapTuple       tuple;
1191         ResultRelInfo *resultRelInfo;
1192         Relation        resultRelationDesc;
1193         int                     numIndices;
1194         Oid                     newId;
1195
1196         /*
1197          * get the heap tuple out of the tuple table slot
1198          */
1199         tuple = slot->val;
1200
1201         /*
1202          * get information on the (current) result relation
1203          */
1204         resultRelInfo = estate->es_result_relation_info;
1205         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1206
1207         /* BEFORE ROW INSERT Triggers */
1208         if (resultRelInfo->ri_TrigDesc &&
1209           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1210         {
1211                 HeapTuple       newtuple;
1212
1213                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1214
1215                 if (newtuple == NULL)   /* "do nothing" */
1216                         return;
1217
1218                 if (newtuple != tuple)  /* modified by Trigger(s) */
1219                 {
1220                         /*
1221                          * Insert modified tuple into tuple table slot, replacing the
1222                          * original.  We assume that it was allocated in per-tuple
1223                          * memory context, and therefore will go away by itself. The
1224                          * tuple table slot should not try to clear it.
1225                          */
1226                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1227                         tuple = newtuple;
1228                 }
1229         }
1230
1231         /*
1232          * Check the constraints of the tuple
1233          */
1234         if (resultRelationDesc->rd_att->constr)
1235                 ExecConstraints("ExecAppend", resultRelInfo, slot, estate);
1236
1237         /*
1238          * insert the tuple
1239          */
1240         newId = heap_insert(resultRelationDesc, tuple);
1241
1242         IncrAppended();
1243         (estate->es_processed)++;
1244         estate->es_lastoid = newId;
1245         setLastTid(&(tuple->t_self));
1246
1247         /*
1248          * process indices
1249          *
1250          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1251          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1252          * field.
1253          */
1254         numIndices = resultRelInfo->ri_NumIndices;
1255         if (numIndices > 0)
1256                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1257
1258         /* AFTER ROW INSERT Triggers */
1259         if (resultRelInfo->ri_TrigDesc)
1260                 ExecARInsertTriggers(estate, resultRelInfo, tuple);
1261 }
1262
1263 /* ----------------------------------------------------------------
1264  *              ExecDelete
1265  *
1266  *              DELETE is like append, we delete the tuple and its
1267  *              index tuples.
1268  * ----------------------------------------------------------------
1269  */
1270 static void
1271 ExecDelete(TupleTableSlot *slot,
1272                    ItemPointer tupleid,
1273                    EState *estate)
1274 {
1275         ResultRelInfo *resultRelInfo;
1276         Relation        resultRelationDesc;
1277         ItemPointerData ctid;
1278         int                     result;
1279
1280         /*
1281          * get information on the (current) result relation
1282          */
1283         resultRelInfo = estate->es_result_relation_info;
1284         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1285
1286         /* BEFORE ROW DELETE Triggers */
1287         if (resultRelInfo->ri_TrigDesc &&
1288           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1289         {
1290                 bool            dodelete;
1291
1292                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
1293
1294                 if (!dodelete)                  /* "do nothing" */
1295                         return;
1296         }
1297
1298         /*
1299          * delete the tuple
1300          */
1301 ldelete:;
1302         result = heap_delete(resultRelationDesc, tupleid, &ctid);
1303         switch (result)
1304         {
1305                 case HeapTupleSelfUpdated:
1306                         return;
1307
1308                 case HeapTupleMayBeUpdated:
1309                         break;
1310
1311                 case HeapTupleUpdated:
1312                         if (XactIsoLevel == XACT_SERIALIZABLE)
1313                                 elog(ERROR, "Can't serialize access due to concurrent update");
1314                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1315                         {
1316                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1317                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1318
1319                                 if (!TupIsNull(epqslot))
1320                                 {
1321                                         *tupleid = ctid;
1322                                         goto ldelete;
1323                                 }
1324                         }
1325                         /* tuple already deleted; nothing to do */
1326                         return;
1327
1328                 default:
1329                         elog(ERROR, "Unknown status %u from heap_delete", result);
1330                         return;
1331         }
1332
1333         IncrDeleted();
1334         (estate->es_processed)++;
1335
1336         /*
1337          * Note: Normally one would think that we have to delete index tuples
1338          * associated with the heap tuple now..
1339          *
1340          * ... but in POSTGRES, we have no need to do this because the vacuum
1341          * daemon automatically opens an index scan and deletes index tuples
1342          * when it finds deleted heap tuples. -cim 9/27/89
1343          */
1344
1345         /* AFTER ROW DELETE Triggers */
1346         if (resultRelInfo->ri_TrigDesc)
1347                 ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1348 }
1349
1350 /* ----------------------------------------------------------------
1351  *              ExecReplace
1352  *
1353  *              note: we can't run replace queries with transactions
1354  *              off because replaces are actually appends and our
1355  *              scan will mistakenly loop forever, replacing the tuple
1356  *              it just appended..      This should be fixed but until it
1357  *              is, we don't want to get stuck in an infinite loop
1358  *              which corrupts your database..
1359  * ----------------------------------------------------------------
1360  */
1361 static void
1362 ExecReplace(TupleTableSlot *slot,
1363                         ItemPointer tupleid,
1364                         EState *estate)
1365 {
1366         HeapTuple       tuple;
1367         ResultRelInfo *resultRelInfo;
1368         Relation        resultRelationDesc;
1369         ItemPointerData ctid;
1370         int                     result;
1371         int                     numIndices;
1372
1373         /*
1374          * abort the operation if not running transactions
1375          */
1376         if (IsBootstrapProcessingMode())
1377         {
1378                 elog(WARNING, "ExecReplace: replace can't run without transactions");
1379                 return;
1380         }
1381
1382         /*
1383          * get the heap tuple out of the tuple table slot
1384          */
1385         tuple = slot->val;
1386
1387         /*
1388          * get information on the (current) result relation
1389          */
1390         resultRelInfo = estate->es_result_relation_info;
1391         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1392
1393         /* BEFORE ROW UPDATE Triggers */
1394         if (resultRelInfo->ri_TrigDesc &&
1395           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1396         {
1397                 HeapTuple       newtuple;
1398
1399                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1400                                                                                 tupleid, tuple);
1401
1402                 if (newtuple == NULL)   /* "do nothing" */
1403                         return;
1404
1405                 if (newtuple != tuple)  /* modified by Trigger(s) */
1406                 {
1407                         /*
1408                          * Insert modified tuple into tuple table slot, replacing the
1409                          * original.  We assume that it was allocated in per-tuple
1410                          * memory context, and therefore will go away by itself. The
1411                          * tuple table slot should not try to clear it.
1412                          */
1413                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1414                         tuple = newtuple;
1415                 }
1416         }
1417
1418         /*
1419          * Check the constraints of the tuple
1420          *
1421          * If we generate a new candidate tuple after EvalPlanQual testing, we
1422          * must loop back here and recheck constraints.  (We don't need to
1423          * redo triggers, however.      If there are any BEFORE triggers then
1424          * trigger.c will have done mark4update to lock the correct tuple, so
1425          * there's no need to do them again.)
1426          */
1427 lreplace:;
1428         if (resultRelationDesc->rd_att->constr)
1429                 ExecConstraints("ExecReplace", resultRelInfo, slot, estate);
1430
1431         /*
1432          * replace the heap tuple
1433          */
1434         result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
1435         switch (result)
1436         {
1437                 case HeapTupleSelfUpdated:
1438                         return;
1439
1440                 case HeapTupleMayBeUpdated:
1441                         break;
1442
1443                 case HeapTupleUpdated:
1444                         if (XactIsoLevel == XACT_SERIALIZABLE)
1445                                 elog(ERROR, "Can't serialize access due to concurrent update");
1446                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1447                         {
1448                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1449                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1450
1451                                 if (!TupIsNull(epqslot))
1452                                 {
1453                                         *tupleid = ctid;
1454                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1455                                         slot = ExecStoreTuple(tuple,
1456                                                                         estate->es_junkFilter->jf_resultSlot,
1457                                                                                   InvalidBuffer, true);
1458                                         goto lreplace;
1459                                 }
1460                         }
1461                         /* tuple already deleted; nothing to do */
1462                         return;
1463
1464                 default:
1465                         elog(ERROR, "Unknown status %u from heap_update", result);
1466                         return;
1467         }
1468
1469         IncrReplaced();
1470         (estate->es_processed)++;
1471
1472         /*
1473          * Note: instead of having to update the old index tuples associated
1474          * with the heap tuple, all we do is form and insert new index tuples.
1475          * This is because replaces are actually deletes and inserts and index
1476          * tuple deletion is done automagically by the vacuum daemon. All we
1477          * do is insert new index tuples.  -cim 9/27/89
1478          */
1479
1480         /*
1481          * process indices
1482          *
1483          * heap_update updates a tuple in the base relation by invalidating it
1484          * and then appending a new tuple to the relation.      As a side effect,
1485          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1486          * field.  So we now insert index tuples using the new tupleid stored
1487          * there.
1488          */
1489
1490         numIndices = resultRelInfo->ri_NumIndices;
1491         if (numIndices > 0)
1492                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
1493
1494         /* AFTER ROW UPDATE Triggers */
1495         if (resultRelInfo->ri_TrigDesc)
1496                 ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1497 }
1498
1499 static char *
1500 ExecRelCheck(ResultRelInfo *resultRelInfo,
1501                          TupleTableSlot *slot, EState *estate)
1502 {
1503         Relation        rel = resultRelInfo->ri_RelationDesc;
1504         int                     ncheck = rel->rd_att->constr->num_check;
1505         ConstrCheck *check = rel->rd_att->constr->check;
1506         ExprContext *econtext;
1507         MemoryContext oldContext;
1508         List       *qual;
1509         int                     i;
1510
1511         /*
1512          * If first time through for this result relation, build expression
1513          * nodetrees for rel's constraint expressions.  Keep them in the
1514          * per-query memory context so they'll survive throughout the query.
1515          */
1516         if (resultRelInfo->ri_ConstraintExprs == NULL)
1517         {
1518                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1519                 resultRelInfo->ri_ConstraintExprs =
1520                         (List **) palloc(ncheck * sizeof(List *));
1521                 for (i = 0; i < ncheck; i++)
1522                 {
1523                         qual = (List *) stringToNode(check[i].ccbin);
1524                         resultRelInfo->ri_ConstraintExprs[i] = qual;
1525                 }
1526                 MemoryContextSwitchTo(oldContext);
1527         }
1528
1529         /*
1530          * We will use the EState's per-tuple context for evaluating
1531          * constraint expressions (creating it if it's not already there).
1532          */
1533         econtext = GetPerTupleExprContext(estate);
1534
1535         /* Arrange for econtext's scan tuple to be the tuple under test */
1536         econtext->ecxt_scantuple = slot;
1537
1538         /* And evaluate the constraints */
1539         for (i = 0; i < ncheck; i++)
1540         {
1541                 qual = resultRelInfo->ri_ConstraintExprs[i];
1542
1543                 /*
1544                  * NOTE: SQL92 specifies that a NULL result from a constraint
1545                  * expression is not to be treated as a failure.  Therefore, tell
1546                  * ExecQual to return TRUE for NULL.
1547                  */
1548                 if (!ExecQual(qual, econtext, true))
1549                         return check[i].ccname;
1550         }
1551
1552         /* NULL result means no error */
1553         return (char *) NULL;
1554 }
1555
1556 void
1557 ExecConstraints(char *caller, ResultRelInfo *resultRelInfo,
1558                                 TupleTableSlot *slot, EState *estate)
1559 {
1560         Relation        rel = resultRelInfo->ri_RelationDesc;
1561         HeapTuple       tuple = slot->val;
1562         TupleConstr *constr = rel->rd_att->constr;
1563
1564         Assert(constr);
1565
1566         if (constr->has_not_null)
1567         {
1568                 int                     natts = rel->rd_att->natts;
1569                 int                     attrChk;
1570
1571                 for (attrChk = 1; attrChk <= natts; attrChk++)
1572                 {
1573                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1574                                 heap_attisnull(tuple, attrChk))
1575                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1576                                          caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1577                 }
1578         }
1579
1580         if (constr->num_check > 0)
1581         {
1582                 char       *failed;
1583
1584                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1585                         elog(ERROR, "%s: rejected due to CHECK constraint %s",
1586                                  caller, failed);
1587         }
1588 }
1589
1590 /*
1591  * Check a modified tuple to see if we want to process its updated version
1592  * under READ COMMITTED rules.
1593  *
1594  * See backend/executor/README for some info about how this works.
1595  */
1596 TupleTableSlot *
1597 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1598 {
1599         evalPlanQual *epq;
1600         EState     *epqstate;
1601         Relation        relation;
1602         HeapTupleData tuple;
1603         HeapTuple       copyTuple = NULL;
1604         int                     rtsize;
1605         bool            endNode;
1606
1607         Assert(rti != 0);
1608
1609         /*
1610          * find relation containing target tuple
1611          */
1612         if (estate->es_result_relation_info != NULL &&
1613                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1614                 relation = estate->es_result_relation_info->ri_RelationDesc;
1615         else
1616         {
1617                 List       *l;
1618
1619                 relation = NULL;
1620                 foreach(l, estate->es_rowMark)
1621                 {
1622                         if (((execRowMark *) lfirst(l))->rti == rti)
1623                         {
1624                                 relation = ((execRowMark *) lfirst(l))->relation;
1625                                 break;
1626                         }
1627                 }
1628                 if (relation == NULL)
1629                         elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1630         }
1631
1632         /*
1633          * fetch tid tuple
1634          *
1635          * Loop here to deal with updated or busy tuples
1636          */
1637         tuple.t_self = *tid;
1638         for (;;)
1639         {
1640                 Buffer          buffer;
1641
1642                 heap_fetch(relation, SnapshotDirty, &tuple, &buffer, NULL);
1643                 if (tuple.t_data != NULL)
1644                 {
1645                         TransactionId xwait = SnapshotDirty->xmax;
1646
1647                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1648                                 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1649
1650                         /*
1651                          * If tuple is being updated by other transaction then we have
1652                          * to wait for its commit/abort.
1653                          */
1654                         if (TransactionIdIsValid(xwait))
1655                         {
1656                                 ReleaseBuffer(buffer);
1657                                 XactLockTableWait(xwait);
1658                                 continue;
1659                         }
1660
1661                         /*
1662                          * We got tuple - now copy it for use by recheck query.
1663                          */
1664                         copyTuple = heap_copytuple(&tuple);
1665                         ReleaseBuffer(buffer);
1666                         break;
1667                 }
1668
1669                 /*
1670                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1671                  * Note that it's possible to get invalid SnapshotDirty->tid if
1672                  * tuple updated by this transaction. Have we to check this ?
1673                  */
1674                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1675                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1676                 {
1677                         /* updated, so look at the updated copy */
1678                         tuple.t_self = SnapshotDirty->tid;
1679                         continue;
1680                 }
1681
1682                 /*
1683                  * Deleted or updated by this transaction; forget it.
1684                  */
1685                 return NULL;
1686         }
1687
1688         /*
1689          * For UPDATE/DELETE we have to return tid of actual row we're
1690          * executing PQ for.
1691          */
1692         *tid = tuple.t_self;
1693
1694         /*
1695          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1696          */
1697         epq = (evalPlanQual *) estate->es_evalPlanQual;
1698         rtsize = length(estate->es_range_table);
1699         endNode = true;
1700
1701         if (epq != NULL && epq->rti == 0)
1702         {
1703                 /* Top PQ stack entry is idle, so re-use it */
1704                 Assert(!(estate->es_useEvalPlan) &&
1705                            epq->estate.es_evalPlanQual == NULL);
1706                 epq->rti = rti;
1707                 endNode = false;
1708         }
1709
1710         /*
1711          * If this is request for another RTE - Ra, - then we have to check
1712          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1713          * updated again and we have to re-start old execution for Ra and
1714          * forget all what we done after Ra was suspended. Cool? -:))
1715          */
1716         if (epq != NULL && epq->rti != rti &&
1717                 epq->estate.es_evTuple[rti - 1] != NULL)
1718         {
1719                 do
1720                 {
1721                         evalPlanQual *oldepq;
1722
1723                         /* pop previous PlanQual from the stack */
1724                         epqstate = &(epq->estate);
1725                         oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1726                         Assert(oldepq->rti != 0);
1727                         /* stop execution */
1728                         ExecEndNode(epq->plan, NULL);
1729                         ExecDropTupleTable(epqstate->es_tupleTable, true);
1730                         epqstate->es_tupleTable = NULL;
1731                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1732                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1733                         /* push current PQ to freePQ stack */
1734                         oldepq->free = epq;
1735                         epq = oldepq;
1736                         estate->es_evalPlanQual = (Pointer) epq;
1737                 } while (epq->rti != rti);
1738         }
1739
1740         /*
1741          * If we are requested for another RTE then we have to suspend
1742          * execution of current PlanQual and start execution for new one.
1743          */
1744         if (epq == NULL || epq->rti != rti)
1745         {
1746                 /* try to reuse plan used previously */
1747                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1748
1749                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1750                 {
1751                         newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1752                         newepq->free = NULL;
1753
1754                         /*
1755                          * Each stack level has its own copy of the plan tree.  This
1756                          * is wasteful, but necessary as long as plan nodes point to
1757                          * exec state nodes rather than vice versa.  Note that
1758                          * copyfuncs.c doesn't attempt to copy the exec state nodes,
1759                          * which is a good thing in this situation.
1760                          */
1761                         newepq->plan = copyObject(estate->es_origPlan);
1762
1763                         /*
1764                          * Init stack level's EState.  We share top level's copy of
1765                          * es_result_relations array and other non-changing status. We
1766                          * need our own tupletable, es_param_exec_vals, and other
1767                          * changeable state.
1768                          */
1769                         epqstate = &(newepq->estate);
1770                         memcpy(epqstate, estate, sizeof(EState));
1771                         epqstate->es_direction = ForwardScanDirection;
1772                         if (estate->es_origPlan->nParamExec > 0)
1773                                 epqstate->es_param_exec_vals = (ParamExecData *)
1774                                         palloc(estate->es_origPlan->nParamExec *
1775                                                    sizeof(ParamExecData));
1776                         epqstate->es_tupleTable = NULL;
1777                         epqstate->es_per_tuple_exprcontext = NULL;
1778
1779                         /*
1780                          * Each epqstate must have its own es_evTupleNull state, but
1781                          * all the stack entries share es_evTuple state.  This allows
1782                          * sub-rechecks to inherit the value being examined by an
1783                          * outer recheck.
1784                          */
1785                         epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
1786                         if (epq == NULL)
1787                         {
1788                                 /* first PQ stack entry */
1789                                 epqstate->es_evTuple = (HeapTuple *)
1790                                         palloc(rtsize * sizeof(HeapTuple));
1791                                 memset(epqstate->es_evTuple, 0, rtsize * sizeof(HeapTuple));
1792                         }
1793                         else
1794                         {
1795                                 /* later stack entries share the same storage */
1796                                 epqstate->es_evTuple = epq->estate.es_evTuple;
1797                         }
1798                 }
1799                 else
1800                 {
1801                         /* recycle previously used EState */
1802                         epqstate = &(newepq->estate);
1803                 }
1804                 /* push current PQ to the stack */
1805                 epqstate->es_evalPlanQual = (Pointer) epq;
1806                 epq = newepq;
1807                 estate->es_evalPlanQual = (Pointer) epq;
1808                 epq->rti = rti;
1809                 endNode = false;
1810         }
1811
1812         Assert(epq->rti == rti);
1813         epqstate = &(epq->estate);
1814
1815         /*
1816          * Ok - we're requested for the same RTE.  Unfortunately we still have
1817          * to end and restart execution of the plan, because ExecReScan
1818          * wouldn't ensure that upper plan nodes would reset themselves.  We
1819          * could make that work if insertion of the target tuple were
1820          * integrated with the Param mechanism somehow, so that the upper plan
1821          * nodes know that their children's outputs have changed.
1822          */
1823         if (endNode)
1824         {
1825                 /* stop execution */
1826                 ExecEndNode(epq->plan, NULL);
1827                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1828                 epqstate->es_tupleTable = NULL;
1829         }
1830
1831         /*
1832          * free old RTE' tuple, if any, and store target tuple where
1833          * relation's scan node will see it
1834          */
1835         if (epqstate->es_evTuple[rti - 1] != NULL)
1836                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1837         epqstate->es_evTuple[rti - 1] = copyTuple;
1838
1839         /*
1840          * Initialize for new recheck query; be careful to copy down state
1841          * that might have changed in top EState.
1842          */
1843         epqstate->es_result_relation_info = estate->es_result_relation_info;
1844         epqstate->es_junkFilter = estate->es_junkFilter;
1845         if (estate->es_origPlan->nParamExec > 0)
1846                 memset(epqstate->es_param_exec_vals, 0,
1847                            estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1848         memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
1849         epqstate->es_useEvalPlan = false;
1850         Assert(epqstate->es_tupleTable == NULL);
1851         epqstate->es_tupleTable =
1852                 ExecCreateTupleTable(estate->es_tupleTable->size);
1853
1854         ExecInitNode(epq->plan, epqstate, NULL);
1855
1856         return EvalPlanQualNext(estate);
1857 }
1858
1859 static TupleTableSlot *
1860 EvalPlanQualNext(EState *estate)
1861 {
1862         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1863         EState     *epqstate = &(epq->estate);
1864         evalPlanQual *oldepq;
1865         TupleTableSlot *slot;
1866
1867         Assert(epq->rti != 0);
1868
1869 lpqnext:;
1870         slot = ExecProcNode(epq->plan, NULL);
1871
1872         /*
1873          * No more tuples for this PQ. Continue previous one.
1874          */
1875         if (TupIsNull(slot))
1876         {
1877                 /* stop execution */
1878                 ExecEndNode(epq->plan, NULL);
1879                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1880                 epqstate->es_tupleTable = NULL;
1881                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1882                 epqstate->es_evTuple[epq->rti - 1] = NULL;
1883                 /* pop old PQ from the stack */
1884                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1885                 if (oldepq == (evalPlanQual *) NULL)
1886                 {
1887                         epq->rti = 0;           /* this is the first (oldest) */
1888                         estate->es_useEvalPlan = false;         /* PQ - mark as free and          */
1889                         return (NULL);          /* continue Query execution   */
1890                 }
1891                 Assert(oldepq->rti != 0);
1892                 /* push current PQ to freePQ stack */
1893                 oldepq->free = epq;
1894                 epq = oldepq;
1895                 epqstate = &(epq->estate);
1896                 estate->es_evalPlanQual = (Pointer) epq;
1897                 goto lpqnext;
1898         }
1899
1900         return (slot);
1901 }
1902
1903 static void
1904 EndEvalPlanQual(EState *estate)
1905 {
1906         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1907         EState     *epqstate = &(epq->estate);
1908         evalPlanQual *oldepq;
1909
1910         if (epq->rti == 0)                      /* plans already shutdowned */
1911         {
1912                 Assert(epq->estate.es_evalPlanQual == NULL);
1913                 return;
1914         }
1915
1916         for (;;)
1917         {
1918                 /* stop execution */
1919                 ExecEndNode(epq->plan, NULL);
1920                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1921                 epqstate->es_tupleTable = NULL;
1922                 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1923                 {
1924                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1925                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1926                 }
1927                 /* pop old PQ from the stack */
1928                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1929                 if (oldepq == (evalPlanQual *) NULL)
1930                 {
1931                         epq->rti = 0;           /* this is the first (oldest) */
1932                         estate->es_useEvalPlan = false;         /* PQ - mark as free */
1933                         break;
1934                 }
1935                 Assert(oldepq->rti != 0);
1936                 /* push current PQ to freePQ stack */
1937                 oldepq->free = epq;
1938                 epq = oldepq;
1939                 epqstate = &(epq->estate);
1940                 estate->es_evalPlanQual = (Pointer) epq;
1941         }
1942 }