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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 'feature' 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 1.137 2001/01/27 05:16:58 tgl Exp $
  31  *
  32  *-------------------------------------------------------------------------
  33  */
  34 #include "postgres.h"
  35
  36 #include "access/heapam.h"
  37 #include "catalog/heap.h"
  38 #include "commands/command.h"
  39 #include "commands/trigger.h"
  40 #include "executor/execdebug.h"
  41 #include "executor/execdefs.h"
  42 #include "miscadmin.h"
  43 #include "optimizer/var.h"
  44 #include "parser/parsetree.h"
  45 #include "utils/acl.h"
  46
  47
  48 /* decls for local routines only used within this module */
  49 static TupleDesc InitPlan(CmdType operation,
  50                  Query *parseTree,
  51                  Plan *plan,
  52                  EState *estate);
  53 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  54                                                           Index resultRelationIndex,
  55                                                           List *rangeTable,
  56                                                           CmdType operation);
  57 static void EndPlan(Plan *plan, EState *estate);
  58 static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
  59                                                                    CmdType operation,
  60                                                                    long numberTuples,
  61                                                                    ScanDirection direction,
  62                                                                    DestReceiver *destfunc);
  63 static void ExecRetrieve(TupleTableSlot *slot,
  64                          DestReceiver *destfunc,
  65                          EState *estate);
  66 static void ExecAppend(TupleTableSlot *slot, ItemPointer tupleid,
  67                    EState *estate);
  68 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  69                    EState *estate);
  70 static void ExecReplace(TupleTableSlot *slot, ItemPointer tupleid,
  71                         EState *estate);
  72 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  73 static void EndEvalPlanQual(EState *estate);
  74 static void ExecCheckQueryPerms(CmdType operation, Query *parseTree,
  75                                                                 Plan *plan);
  76 static void ExecCheckPlanPerms(Plan *plan, List *rangeTable,
  77                                                            CmdType operation);
  78 static void ExecCheckRTPerms(List *rangeTable, CmdType operation);
  79 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
  80
  81 /* end of local decls */
  82
  83
  84 /* ----------------------------------------------------------------
  85  *              ExecutorStart
  86  *
  87  *              This routine must be called at the beginning of any execution of any
  88  *              query plan
  89  *
  90  *              returns a TupleDesc which describes the attributes of the tuples to
  91  *              be returned by the query.
  92  *
  93  * NB: the CurrentMemoryContext when this is called must be the context
  94  * to be used as the per-query context for the query plan.  ExecutorRun()
  95  * and ExecutorEnd() must be called in this same memory context.
  96  * ----------------------------------------------------------------
  97  */
  98 TupleDesc
  99 ExecutorStart(QueryDesc *queryDesc, EState *estate)
 100 {
 101         TupleDesc       result;
 102
 103         /* sanity checks */
 104         Assert(queryDesc != NULL);
 105
 106         if (queryDesc->plantree->nParamExec > 0)
 107         {
 108                 estate->es_param_exec_vals = (ParamExecData *)
 109                         palloc(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 110                 MemSet(estate->es_param_exec_vals, 0,
 111                            queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 112         }
 113
 114         /*
 115          * Make our own private copy of the current queries snapshot data
 116          */
 117         if (QuerySnapshot == NULL)
 118                 estate->es_snapshot = NULL;
 119         else
 120         {
 121                 estate->es_snapshot = (Snapshot) palloc(sizeof(SnapshotData));
 122                 memcpy(estate->es_snapshot, QuerySnapshot, sizeof(SnapshotData));
 123                 if (estate->es_snapshot->xcnt > 0)
 124                 {
 125                         estate->es_snapshot->xip = (TransactionId *)
 126                                 palloc(estate->es_snapshot->xcnt * sizeof(TransactionId));
 127                         memcpy(estate->es_snapshot->xip, QuerySnapshot->xip,
 128                                    estate->es_snapshot->xcnt * sizeof(TransactionId));
 129                 }
 130         }
 131
 132         /*
 133          * Initialize the plan
 134          */
 135         result = InitPlan(queryDesc->operation,
 136                                           queryDesc->parsetree,
 137                                           queryDesc->plantree,
 138                                           estate);
 139
 140         return result;
 141 }
 142
 143 /* ----------------------------------------------------------------
 144  *              ExecutorRun
 145  *
 146  *              This is the main routine of the executor module. It accepts
 147  *              the query descriptor from the traffic cop and executes the
 148  *              query plan.
 149  *
 150  *              ExecutorStart must have been called already.
 151  *
 152  *              the different features supported are:
 153  *                       EXEC_RUN:      retrieve all tuples in the forward direction
 154  *                       EXEC_FOR:      retrieve 'count' number of tuples in the forward dir
 155  *                       EXEC_BACK: retrieve 'count' number of tuples in the backward dir
 156  *                       EXEC_RETONE: return one tuple but don't 'retrieve' it
 157  *                                                 used in postquel function processing
 158  *
 159  *              Note: count = 0 is interpreted as "no limit".
 160  *
 161  * ----------------------------------------------------------------
 162  */
 163 TupleTableSlot *
 164 ExecutorRun(QueryDesc *queryDesc, EState *estate, int feature, long count)
 165 {
 166         CmdType         operation;
 167         Plan       *plan;
 168         TupleTableSlot *result;
 169         CommandDest dest;
 170         DestReceiver *destfunc;
 171
 172         /*
 173          * sanity checks
 174          */
 175         Assert(queryDesc != NULL);
 176
 177         /*
 178          * extract information from the query descriptor and the query
 179          * feature.
 180          */
 181         operation = queryDesc->operation;
 182         plan = queryDesc->plantree;
 183         dest = queryDesc->dest;
 184         destfunc = DestToFunction(dest);
 185         estate->es_processed = 0;
 186         estate->es_lastoid = InvalidOid;
 187
 188         /*
 189          * FIXME: the dest setup function ought to be handed the tuple desc
 190          * for the tuples to be output, but I'm not quite sure how to get that
 191          * info at this point.  For now, passing NULL is OK because no
 192          * existing dest setup function actually uses the pointer.
 193          */
 194         (*destfunc->setup) (destfunc, (TupleDesc) NULL);
 195
 196         switch (feature)
 197         {
 198                 case EXEC_RUN:
 199                         result = ExecutePlan(estate,
 200                                                                  plan,
 201                                                                  operation,
 202                                                                  count,
 203                                                                  ForwardScanDirection,
 204                                                                  destfunc);
 205                         break;
 206
 207                 case EXEC_FOR:
 208                         result = ExecutePlan(estate,
 209                                                                  plan,
 210                                                                  operation,
 211                                                                  count,
 212                                                                  ForwardScanDirection,
 213                                                                  destfunc);
 214                         break;
 215
 216                         /*
 217                          * retrieve next n "backward" tuples
 218                          */
 219                 case EXEC_BACK:
 220                         result = ExecutePlan(estate,
 221                                                                  plan,
 222                                                                  operation,
 223                                                                  count,
 224                                                                  BackwardScanDirection,
 225                                                                  destfunc);
 226                         break;
 227
 228                         /*
 229                          * return one tuple but don't "retrieve" it. (this is used by
 230                          * the rule manager..) -cim 9/14/89
 231                          */
 232                 case EXEC_RETONE:
 233                         result = ExecutePlan(estate,
 234                                                                  plan,
 235                                                                  operation,
 236                                                                  ONE_TUPLE,
 237                                                                  ForwardScanDirection,
 238                                                                  destfunc);
 239                         break;
 240
 241                 default:
 242                         elog(DEBUG, "ExecutorRun: Unknown feature %d", feature);
 243                         result = NULL;
 244                         break;
 245         }
 246
 247         (*destfunc->cleanup) (destfunc);
 248
 249         return result;
 250 }
 251
 252 /* ----------------------------------------------------------------
 253  *              ExecutorEnd
 254  *
 255  *              This routine must be called at the end of any execution of any
 256  *              query plan
 257  *
 258  *              returns (AttrInfo*) which describes the attributes of the tuples to
 259  *              be returned by the query.
 260  *
 261  * ----------------------------------------------------------------
 262  */
 263 void
 264 ExecutorEnd(QueryDesc *queryDesc, EState *estate)
 265 {
 266         /* sanity checks */
 267         Assert(queryDesc != NULL);
 268
 269         EndPlan(queryDesc->plantree, estate);
 270
 271         /* XXX - clean up some more from ExecutorStart() - er1p */
 272         if (NULL == estate->es_snapshot)
 273         {
 274                 /* nothing to free */
 275         }
 276         else
 277         {
 278                 if (estate->es_snapshot->xcnt > 0)
 279                         pfree(estate->es_snapshot->xip);
 280                 pfree(estate->es_snapshot);
 281         }
 282
 283         if (NULL == estate->es_param_exec_vals)
 284         {
 285                 /* nothing to free */
 286         }
 287         else
 288         {
 289                 pfree(estate->es_param_exec_vals);
 290                 estate->es_param_exec_vals = NULL;
 291         }
 292 }
 293
 294
 295 /*
 296  * ExecCheckQueryPerms
 297  *              Check access permissions for all relations referenced in a query.
 298  */
 299 static void
 300 ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
 301 {
 302         /*
 303          * Check RTEs in the query's primary rangetable.
 304          */
 305         ExecCheckRTPerms(parseTree->rtable, operation);
 306
 307         /*
 308          * Search for subplans and APPEND nodes to check their rangetables.
 309          */
 310         ExecCheckPlanPerms(plan, parseTree->rtable, operation);
 311 }
 312
 313 /*
 314  * ExecCheckPlanPerms
 315  *              Recursively scan the plan tree to check access permissions in
 316  *              subplans.
 317  */
 318 static void
 319 ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
 320 {
 321         List       *subp;
 322
 323         if (plan == NULL)
 324                 return;
 325
 326         /* Check subplans, which we assume are plain SELECT queries */
 327
 328         foreach(subp, plan->initPlan)
 329         {
 330                 SubPlan    *subplan = (SubPlan *) lfirst(subp);
 331
 332                 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 333                 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
 334         }
 335         foreach(subp, plan->subPlan)
 336         {
 337                 SubPlan    *subplan = (SubPlan *) lfirst(subp);
 338
 339                 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 340                 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
 341         }
 342
 343         /* Check lower plan nodes */
 344
 345         ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
 346         ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
 347
 348         /* Do node-type-specific checks */
 349
 350         switch (nodeTag(plan))
 351         {
 352                 case T_SubqueryScan:
 353                         {
 354                                 SubqueryScan   *scan = (SubqueryScan *) plan;
 355                                 RangeTblEntry *rte;
 356
 357                                 /* Recursively check the subquery */
 358                                 rte = rt_fetch(scan->scan.scanrelid, rangeTable);
 359                                 Assert(rte->subquery != NULL);
 360                                 ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
 361                                 break;
 362                         }
 363                 case T_Append:
 364                         {
 365                                 Append     *app = (Append *) plan;
 366                                 List       *appendplans;
 367
 368                                 foreach(appendplans, app->appendplans)
 369                                 {
 370                                         ExecCheckPlanPerms((Plan *) lfirst(appendplans),
 371                                                                            rangeTable,
 372                                                                            operation);
 373                                 }
 374                                 break;
 375                         }
 376
 377                 default:
 378                         break;
 379         }
 380 }
 381
 382 /*
 383  * ExecCheckRTPerms
 384  *              Check access permissions for all relations listed in a range table.
 385  */
 386 static void
 387 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 388 {
 389         List       *lp;
 390
 391         foreach(lp, rangeTable)
 392         {
 393                 RangeTblEntry *rte = lfirst(lp);
 394
 395                 ExecCheckRTEPerms(rte, operation);
 396         }
 397 }
 398
 399 /*
 400  * ExecCheckRTEPerms
 401  *              Check access permissions for a single RTE.
 402  */
 403 static void
 404 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 405 {
 406         char       *relName;
 407         Oid                     userid;
 408         int32           aclcheck_result;
 409
 410         /*
 411          * If it's a subquery RTE, ignore it --- it will be checked when
 412          * ExecCheckPlanPerms finds the SubqueryScan node for it.
 413          */
 414         if (rte->subquery)
 415                 return;
 416
 417         relName = rte->relname;
 418
 419         /*
 420          * userid to check as: current user unless we have a setuid indication.
 421          *
 422          * Note: GetUserId() is presently fast enough that there's no harm
 423          * in calling it separately for each RTE.  If that stops being true,
 424          * we could call it once in ExecCheckQueryPerms and pass the userid
 425          * down from there.  But for now, no need for the extra clutter.
 426          */
 427         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 428
 429 #define CHECK(MODE)             pg_aclcheck(relName, userid, MODE)
 430
 431         if (rte->checkForRead)
 432         {
 433                 aclcheck_result = CHECK(ACL_RD);
 434                 if (aclcheck_result != ACLCHECK_OK)
 435                         elog(ERROR, "%s: %s",
 436                                  relName, aclcheck_error_strings[aclcheck_result]);
 437         }
 438
 439         if (rte->checkForWrite)
 440         {
 441                 /*
 442                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 443                  * Right now we don't distinguish that from true update as far as
 444                  * permissions checks are concerned.
 445                  */
 446                 switch (operation)
 447                 {
 448                         case CMD_INSERT:
 449                                 /* Accept either APPEND or WRITE access for this */
 450                                 aclcheck_result = CHECK(ACL_AP);
 451                                 if (aclcheck_result != ACLCHECK_OK)
 452                                         aclcheck_result = CHECK(ACL_WR);
 453                                 break;
 454                         case CMD_SELECT:
 455                         case CMD_DELETE:
 456                         case CMD_UPDATE:
 457                                 aclcheck_result = CHECK(ACL_WR);
 458                                 break;
 459                         default:
 460                                 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
 461                                          operation);
 462                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 463                                 break;
 464                 }
 465                 if (aclcheck_result != ACLCHECK_OK)
 466                         elog(ERROR, "%s: %s",
 467                                  relName, aclcheck_error_strings[aclcheck_result]);
 468         }
 469 }
 470
 471
 472 /* ===============================================================
 473  * ===============================================================
 474                                                  static routines follow
 475  * ===============================================================
 476  * ===============================================================
 477  */
 478
 479 typedef struct execRowMark
 480 {
 481         Relation        relation;
 482         Index           rti;
 483         char            resname[32];
 484 } execRowMark;
 485
 486 typedef struct evalPlanQual
 487 {
 488         Plan       *plan;
 489         Index           rti;
 490         EState          estate;
 491         struct evalPlanQual *free;
 492 } evalPlanQual;
 493
 494 /* ----------------------------------------------------------------
 495  *              InitPlan
 496  *
 497  *              Initializes the query plan: open files, allocate storage
 498  *              and start up the rule manager
 499  * ----------------------------------------------------------------
 500  */
 501 static TupleDesc
 502 InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
 503 {
 504         List       *rangeTable;
 505         Relation        intoRelationDesc;
 506         TupleDesc       tupType;
 507
 508         /*
 509          * Do permissions checks.
 510          */
 511         ExecCheckQueryPerms(operation, parseTree, plan);
 512
 513         /*
 514          * get information from query descriptor
 515          */
 516         rangeTable = parseTree->rtable;
 517
 518         /*
 519          * initialize the node's execution state
 520          */
 521         estate->es_range_table = rangeTable;
 522
 523         /*
 524          * if there is a result relation, initialize result relation stuff
 525          */
 526         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 527         {
 528                 List       *resultRelations = parseTree->resultRelations;
 529                 int                     numResultRelations;
 530                 ResultRelInfo *resultRelInfos;
 531
 532                 if (resultRelations != NIL)
 533                 {
 534                         /*
 535                          * Multiple result relations (due to inheritance)
 536                          * parseTree->resultRelations identifies them all
 537                          */
 538                         ResultRelInfo *resultRelInfo;
 539
 540                         numResultRelations = length(resultRelations);
 541                         resultRelInfos = (ResultRelInfo *)
 542                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 543                         resultRelInfo = resultRelInfos;
 544                         while (resultRelations != NIL)
 545                         {
 546                                 initResultRelInfo(resultRelInfo,
 547                                                                   lfirsti(resultRelations),
 548                                                                   rangeTable,
 549                                                                   operation);
 550                                 resultRelInfo++;
 551                                 resultRelations = lnext(resultRelations);
 552                         }
 553                 }
 554                 else
 555                 {
 556                         /*
 557                          * Single result relation identified by parseTree->resultRelation
 558                          */
 559                         numResultRelations = 1;
 560                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 561                         initResultRelInfo(resultRelInfos,
 562                                                           parseTree->resultRelation,
 563                                                           rangeTable,
 564                                                           operation);
 565                 }
 566
 567                 estate->es_result_relations = resultRelInfos;
 568                 estate->es_num_result_relations = numResultRelations;
 569                 /* Initialize to first or only result rel */
 570                 estate->es_result_relation_info = resultRelInfos;
 571         }
 572         else
 573         {
 574                 /*
 575                  * if no result relation, then set state appropriately
 576                  */
 577                 estate->es_result_relations = NULL;
 578                 estate->es_num_result_relations = 0;
 579                 estate->es_result_relation_info = NULL;
 580         }
 581
 582         /*
 583          * Have to lock relations selected for update
 584          */
 585         estate->es_rowMark = NIL;
 586         if (parseTree->rowMarks != NIL)
 587         {
 588                 List       *l;
 589
 590                 foreach(l, parseTree->rowMarks)
 591                 {
 592                         Index           rti = lfirsti(l);
 593                         Oid                     relid = getrelid(rti, rangeTable);
 594                         Relation        relation;
 595                         execRowMark *erm;
 596
 597                         relation = heap_open(relid, RowShareLock);
 598                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 599                         erm->relation = relation;
 600                         erm->rti = rti;
 601                         sprintf(erm->resname, "ctid%u", rti);
 602                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 603                 }
 604         }
 605
 606         /*
 607          * initialize the executor "tuple" table.
 608          */
 609         {
 610                 int                     nSlots = ExecCountSlotsNode(plan);
 611                 TupleTable      tupleTable = ExecCreateTupleTable(nSlots + 10);         /* why add ten? - jolly */
 612
 613                 estate->es_tupleTable = tupleTable;
 614         }
 615
 616         /*
 617          * initialize the private state information for all the nodes in the
 618          * query tree.  This opens files, allocates storage and leaves us
 619          * ready to start processing tuples.
 620          */
 621         ExecInitNode(plan, estate, NULL);
 622
 623         /*
 624          * Get the tuple descriptor describing the type of tuples to return.
 625          * (this is especially important if we are creating a relation with
 626          * "retrieve into")
 627          */
 628         tupType = ExecGetTupType(plan);         /* tuple descriptor */
 629
 630         /*
 631          * Initialize the junk filter if needed. SELECT and INSERT queries need
 632          * a filter if there are any junk attrs in the tlist.  UPDATE and
 633          * DELETE always need one, since there's always a junk 'ctid' attribute
 634          * present --- no need to look first.
 635          */
 636         {
 637                 bool            junk_filter_needed = false;
 638                 List       *tlist;
 639
 640                 switch (operation)
 641                 {
 642                         case CMD_SELECT:
 643                         case CMD_INSERT:
 644                                 foreach(tlist, plan->targetlist)
 645                                 {
 646                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 647
 648                                         if (tle->resdom->resjunk)
 649                                         {
 650                                                 junk_filter_needed = true;
 651                                                 break;
 652                                         }
 653                                 }
 654                                 break;
 655                         case CMD_UPDATE:
 656                         case CMD_DELETE:
 657                                 junk_filter_needed = true;
 658                                 break;
 659                         default:
 660                                 break;
 661                 }
 662
 663                 if (junk_filter_needed)
 664                 {
 665                         /*
 666                          * If there are multiple result relations, each one needs
 667                          * its own junk filter.  Note this is only possible for
 668                          * UPDATE/DELETE, so we can't be fooled by some needing
 669                          * a filter and some not.
 670                          */
 671                         if (parseTree->resultRelations != NIL)
 672                         {
 673                                 List       *subplans;
 674                                 ResultRelInfo *resultRelInfo;
 675
 676                                 /* Top plan had better be an Append here. */
 677                                 Assert(IsA(plan, Append));
 678                                 Assert(((Append *) plan)->isTarget);
 679                                 subplans = ((Append *) plan)->appendplans;
 680                                 Assert(length(subplans) == estate->es_num_result_relations);
 681                                 resultRelInfo = estate->es_result_relations;
 682                                 while (subplans != NIL)
 683                                 {
 684                                         Plan       *subplan = (Plan *) lfirst(subplans);
 685                                         JunkFilter *j;
 686
 687                                         j = ExecInitJunkFilter(subplan->targetlist,
 688                                                                                    ExecGetTupType(subplan));
 689                                         resultRelInfo->ri_junkFilter = j;
 690                                         resultRelInfo++;
 691                                         subplans = lnext(subplans);
 692                                 }
 693                                 /*
 694                                  * Set active junkfilter too; at this point ExecInitAppend
 695                                  * has already selected an active result relation...
 696                                  */
 697                                 estate->es_junkFilter =
 698                                         estate->es_result_relation_info->ri_junkFilter;
 699                         }
 700                         else
 701                         {
 702                                 /* Normal case with just one JunkFilter */
 703                                 JunkFilter *j = ExecInitJunkFilter(plan->targetlist,
 704                                                                                                    tupType);
 705
 706                                 estate->es_junkFilter = j;
 707                                 if (estate->es_result_relation_info)
 708                                         estate->es_result_relation_info->ri_junkFilter = j;
 709
 710                                 /* For SELECT, want to return the cleaned tuple type */
 711                                 if (operation == CMD_SELECT)
 712                                         tupType = j->jf_cleanTupType;
 713                         }
 714                 }
 715                 else
 716                         estate->es_junkFilter = NULL;
 717         }
 718
 719         /*
 720          * initialize the "into" relation
 721          */
 722         intoRelationDesc = (Relation) NULL;
 723
 724         if (operation == CMD_SELECT)
 725         {
 726                 char       *intoName;
 727                 Oid                     intoRelationId;
 728                 TupleDesc       tupdesc;
 729
 730                 if (!parseTree->isPortal)
 731                 {
 732
 733                         /*
 734                          * a select into table
 735                          */
 736                         if (parseTree->into != NULL)
 737                         {
 738
 739                                 /*
 740                                  * create the "into" relation
 741                                  */
 742                                 intoName = parseTree->into;
 743
 744                                 /*
 745                                  * have to copy tupType to get rid of constraints
 746                                  */
 747                                 tupdesc = CreateTupleDescCopy(tupType);
 748
 749                                 intoRelationId =
 750                                         heap_create_with_catalog(intoName,
 751                                                                                          tupdesc,
 752                                                                                          RELKIND_RELATION,
 753                                                                                          parseTree->isTemp,
 754                                                                                          allowSystemTableMods);
 755
 756                                 FreeTupleDesc(tupdesc);
 757
 758                                 /*
 759                                  * Advance command counter so that the newly-created
 760                                  * relation's catalog tuples will be visible to heap_open.
 761                                  */
 762                                 CommandCounterIncrement();
 763
 764                                 /*
 765                                  * If necessary, create a TOAST table for the into relation.
 766                                  * Note that AlterTableCreateToastTable ends with
 767                                  * CommandCounterIncrement(), so that the TOAST table will
 768                                  * be visible for insertion.
 769                                  */
 770                                 AlterTableCreateToastTable(intoName, true);
 771
 772                                 intoRelationDesc = heap_open(intoRelationId,
 773                                                                                          AccessExclusiveLock);
 774                         }
 775                 }
 776         }
 777
 778         estate->es_into_relation_descriptor = intoRelationDesc;
 779
 780         estate->es_origPlan = plan;
 781         estate->es_evalPlanQual = NULL;
 782         estate->es_evTuple = NULL;
 783         estate->es_useEvalPlan = false;
 784
 785         return tupType;
 786 }
 787
 788 /*
 789  * Initialize ResultRelInfo data for one result relation
 790  */
 791 static void
 792 initResultRelInfo(ResultRelInfo *resultRelInfo,
 793                                   Index resultRelationIndex,
 794                                   List *rangeTable,
 795                                   CmdType operation)
 796 {
 797         Oid                     resultRelationOid;
 798         Relation        resultRelationDesc;
 799
 800         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 801         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 802
 803         switch (resultRelationDesc->rd_rel->relkind)
 804         {
 805                 case RELKIND_SEQUENCE:
 806                         elog(ERROR, "You can't change sequence relation %s",
 807                                  RelationGetRelationName(resultRelationDesc));
 808                         break;
 809                 case RELKIND_TOASTVALUE:
 810                         elog(ERROR, "You can't change toast relation %s",
 811                                  RelationGetRelationName(resultRelationDesc));
 812                         break;
 813                 case RELKIND_VIEW:
 814                         elog(ERROR, "You can't change view relation %s",
 815                                  RelationGetRelationName(resultRelationDesc));
 816                         break;
 817         }
 818
 819         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 820         resultRelInfo->type = T_ResultRelInfo;
 821         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 822         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 823         resultRelInfo->ri_NumIndices = 0;
 824         resultRelInfo->ri_IndexRelationDescs = NULL;
 825         resultRelInfo->ri_IndexRelationInfo = NULL;
 826         resultRelInfo->ri_ConstraintExprs = NULL;
 827         resultRelInfo->ri_junkFilter = NULL;
 828
 829         /*
 830          * If there are indices on the result relation, open them and save
 831          * descriptors in the result relation info, so that we can add new
 832          * index entries for the tuples we add/update.  We need not do
 833          * this for a DELETE, however, since deletion doesn't affect
 834          * indexes.
 835          */
 836         if (resultRelationDesc->rd_rel->relhasindex &&
 837                 operation != CMD_DELETE)
 838                 ExecOpenIndices(resultRelInfo);
 839 }
 840
 841 /* ----------------------------------------------------------------
 842  *              EndPlan
 843  *
 844  *              Cleans up the query plan -- closes files and free up storages
 845  * ----------------------------------------------------------------
 846  */
 847 static void
 848 EndPlan(Plan *plan, EState *estate)
 849 {
 850         ResultRelInfo *resultRelInfo;
 851         int                     i;
 852         List       *l;
 853
 854         /*
 855          * shut down any PlanQual processing we were doing
 856          */
 857         if (estate->es_evalPlanQual != NULL)
 858                 EndEvalPlanQual(estate);
 859
 860         /*
 861          * shut down the node-type-specific query processing
 862          */
 863         ExecEndNode(plan, plan);
 864
 865         /*
 866          * destroy the executor "tuple" table.
 867          */
 868         ExecDropTupleTable(estate->es_tupleTable, true);
 869         estate->es_tupleTable = NULL;
 870
 871         /*
 872          * close the result relation(s) if any, but hold locks
 873          * until xact commit.
 874          */
 875         resultRelInfo = estate->es_result_relations;
 876         for (i = estate->es_num_result_relations; i > 0; i--)
 877         {
 878                 /* Close indices and then the relation itself */
 879                 ExecCloseIndices(resultRelInfo);
 880                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 881                 resultRelInfo++;
 882         }
 883
 884         /*
 885          * close the "into" relation if necessary, again keeping lock
 886          */
 887         if (estate->es_into_relation_descriptor != NULL)
 888                 heap_close(estate->es_into_relation_descriptor, NoLock);
 889
 890         /*
 891          * close any relations selected FOR UPDATE, again keeping locks
 892          */
 893         foreach(l, estate->es_rowMark)
 894         {
 895                 execRowMark *erm = lfirst(l);
 896
 897                 heap_close(erm->relation, NoLock);
 898         }
 899 }
 900
 901 /* ----------------------------------------------------------------
 902  *              ExecutePlan
 903  *
 904  *              processes the query plan to retrieve 'numberTuples' tuples in the
 905  *              direction specified.
 906  *              Retrieves all tuples if tupleCount is 0
 907  *
 908  *              result is either a slot containing the last tuple in the case
 909  *              of a RETRIEVE or NULL otherwise.
 910  *
 911  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 912  * user can see it
 913  * ----------------------------------------------------------------
 914  */
 915 static TupleTableSlot *
 916 ExecutePlan(EState *estate,
 917                         Plan *plan,
 918                         CmdType operation,
 919                         long numberTuples,
 920                         ScanDirection direction,
 921                         DestReceiver *destfunc)
 922 {
 923         JunkFilter *junkfilter;
 924         TupleTableSlot *slot;
 925         ItemPointer tupleid = NULL;
 926         ItemPointerData tuple_ctid;
 927         long            current_tuple_count;
 928         TupleTableSlot *result;
 929
 930         /*
 931          * initialize local variables
 932          */
 933         slot = NULL;
 934         current_tuple_count = 0;
 935         result = NULL;
 936
 937         /*
 938          * Set the direction.
 939          */
 940         estate->es_direction = direction;
 941
 942         /*
 943          * Loop until we've processed the proper number of tuples from the
 944          * plan.
 945          */
 946
 947         for (;;)
 948         {
 949                 /* Reset the per-output-tuple exprcontext */
 950                 ResetPerTupleExprContext(estate);
 951
 952                 /*
 953                  * Execute the plan and obtain a tuple
 954                  */
 955                 /* at the top level, the parent of a plan (2nd arg) is itself */
 956 lnext:  ;
 957                 if (estate->es_useEvalPlan)
 958                 {
 959                         slot = EvalPlanQualNext(estate);
 960                         if (TupIsNull(slot))
 961                                 slot = ExecProcNode(plan, plan);
 962                 }
 963                 else
 964                         slot = ExecProcNode(plan, plan);
 965
 966                 /*
 967                  * if the tuple is null, then we assume there is nothing more to
 968                  * process so we just return null...
 969                  */
 970                 if (TupIsNull(slot))
 971                 {
 972                         result = NULL;
 973                         break;
 974                 }
 975
 976                 /*
 977                  * if we have a junk filter, then project a new tuple with the
 978                  * junk removed.
 979                  *
 980                  * Store this new "clean" tuple in the place of the original tuple.
 981                  *
 982                  * Also, extract all the junk information we need.
 983                  */
 984                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
 985                 {
 986                         Datum           datum;
 987                         HeapTuple       newTuple;
 988                         bool            isNull;
 989
 990                         /*
 991                          * extract the 'ctid' junk attribute.
 992                          */
 993                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
 994                         {
 995                                 if (!ExecGetJunkAttribute(junkfilter,
 996                                                                                   slot,
 997                                                                                   "ctid",
 998                                                                                   &datum,
 999                                                                                   &isNull))
1000                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
1001
1002                                 /* shouldn't ever get a null result... */
1003                                 if (isNull)
1004                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
1005
1006                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1007                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1008                                                                                  * ctid!! */
1009                                 tupleid = &tuple_ctid;
1010                         }
1011                         else if (estate->es_rowMark != NIL)
1012                         {
1013                                 List       *l;
1014
1015                 lmark:  ;
1016                                 foreach(l, estate->es_rowMark)
1017                                 {
1018                                         execRowMark *erm = lfirst(l);
1019                                         Buffer          buffer;
1020                                         HeapTupleData tuple;
1021                                         TupleTableSlot *newSlot;
1022                                         int                     test;
1023
1024                                         if (!ExecGetJunkAttribute(junkfilter,
1025                                                                                           slot,
1026                                                                                           erm->resname,
1027                                                                                           &datum,
1028                                                                                           &isNull))
1029                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1030                                                          erm->resname);
1031
1032                                         /*
1033                                          * Unlike the UPDATE/DELETE case, a null result is
1034                                          * possible here, when the referenced table is on the
1035                                          * nullable side of an outer join.  Ignore nulls.
1036                                          */
1037                                         if (isNull)
1038                                                 continue;
1039
1040                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1041                                         test = heap_mark4update(erm->relation, &tuple, &buffer);
1042                                         ReleaseBuffer(buffer);
1043                                         switch (test)
1044                                         {
1045                                                 case HeapTupleSelfUpdated:
1046                                                 case HeapTupleMayBeUpdated:
1047                                                         break;
1048
1049                                                 case HeapTupleUpdated:
1050                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1051                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1052                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1053                                                                   (ItemPointer) DatumGetPointer(datum))))
1054                                                         {
1055                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1056                                                                 if (!(TupIsNull(newSlot)))
1057                                                                 {
1058                                                                         slot = newSlot;
1059                                                                         estate->es_useEvalPlan = true;
1060                                                                         goto lmark;
1061                                                                 }
1062                                                         }
1063
1064                                                         /*
1065                                                          * if tuple was deleted or PlanQual failed for
1066                                                          * updated tuple - we have not return this
1067                                                          * tuple!
1068                                                          */
1069                                                         goto lnext;
1070
1071                                                 default:
1072                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1073                                                         return (NULL);
1074                                         }
1075                                 }
1076                         }
1077
1078                         /*
1079                          * Finally create a new "clean" tuple with all junk attributes
1080                          * removed
1081                          */
1082                         newTuple = ExecRemoveJunk(junkfilter, slot);
1083
1084                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1085                                                                   slot, /* destination slot */
1086                                                                   InvalidBuffer,                /* this tuple has no
1087                                                                                                                  * buffer */
1088                                                                   true);                /* tuple should be pfreed */
1089                 }                                               /* if (junkfilter... */
1090
1091                 /*
1092                  * now that we have a tuple, do the appropriate thing with it..
1093                  * either return it to the user, add it to a relation someplace,
1094                  * delete it from a relation, or modify some of its attributes.
1095                  */
1096
1097                 switch (operation)
1098                 {
1099                         case CMD_SELECT:
1100                                 ExecRetrieve(slot,              /* slot containing tuple */
1101                                                          destfunc,      /* destination's tuple-receiver
1102                                                                                  * obj */
1103                                                          estate);       /* */
1104                                 result = slot;
1105                                 break;
1106
1107                         case CMD_INSERT:
1108                                 ExecAppend(slot, tupleid, estate);
1109                                 result = NULL;
1110                                 break;
1111
1112                         case CMD_DELETE:
1113                                 ExecDelete(slot, tupleid, estate);
1114                                 result = NULL;
1115                                 break;
1116
1117                         case CMD_UPDATE:
1118                                 ExecReplace(slot, tupleid, estate);
1119                                 result = NULL;
1120                                 break;
1121
1122                         default:
1123                                 elog(DEBUG, "ExecutePlan: unknown operation in queryDesc");
1124                                 result = NULL;
1125                                 break;
1126                 }
1127
1128                 /*
1129                  * check our tuple count.. if we've processed the proper number
1130                  * then quit, else loop again and process more tuples..
1131                  */
1132                 current_tuple_count++;
1133                 if (numberTuples == current_tuple_count)
1134                         break;
1135         }
1136
1137         /*
1138          * here, result is either a slot containing a tuple in the case of a
1139          * RETRIEVE or NULL otherwise.
1140          */
1141         return result;
1142 }
1143
1144 /* ----------------------------------------------------------------
1145  *              ExecRetrieve
1146  *
1147  *              RETRIEVEs are easy.. we just pass the tuple to the appropriate
1148  *              print function.  The only complexity is when we do a
1149  *              "retrieve into", in which case we insert the tuple into
1150  *              the appropriate relation (note: this is a newly created relation
1151  *              so we don't need to worry about indices or locks.)
1152  * ----------------------------------------------------------------
1153  */
1154 static void
1155 ExecRetrieve(TupleTableSlot *slot,
1156                          DestReceiver *destfunc,
1157                          EState *estate)
1158 {
1159         HeapTuple       tuple;
1160         TupleDesc       attrtype;
1161
1162         /*
1163          * get the heap tuple out of the tuple table slot
1164          */
1165         tuple = slot->val;
1166         attrtype = slot->ttc_tupleDescriptor;
1167
1168         /*
1169          * insert the tuple into the "into relation"
1170          */
1171         if (estate->es_into_relation_descriptor != NULL)
1172         {
1173                 heap_insert(estate->es_into_relation_descriptor, tuple);
1174                 IncrAppended();
1175         }
1176
1177         /*
1178          * send the tuple to the front end (or the screen)
1179          */
1180         (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1181         IncrRetrieved();
1182         (estate->es_processed)++;
1183 }
1184
1185 /* ----------------------------------------------------------------
1186  *              ExecAppend
1187  *
1188  *              APPENDs are trickier.. we have to insert the tuple into
1189  *              the base relation and insert appropriate tuples into the
1190  *              index relations.
1191  * ----------------------------------------------------------------
1192  */
1193
1194 static void
1195 ExecAppend(TupleTableSlot *slot,
1196                    ItemPointer tupleid,
1197                    EState *estate)
1198 {
1199         HeapTuple       tuple;
1200         ResultRelInfo *resultRelInfo;
1201         Relation        resultRelationDesc;
1202         int                     numIndices;
1203         Oid                     newId;
1204
1205         /*
1206          * get the heap tuple out of the tuple table slot
1207          */
1208         tuple = slot->val;
1209
1210         /*
1211          * get information on the (current) result relation
1212          */
1213         resultRelInfo = estate->es_result_relation_info;
1214         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1215
1216         /* BEFORE ROW INSERT Triggers */
1217         if (resultRelationDesc->trigdesc &&
1218                 resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1219         {
1220                 HeapTuple       newtuple;
1221
1222                 newtuple = ExecBRInsertTriggers(estate, resultRelationDesc, tuple);
1223
1224                 if (newtuple == NULL)   /* "do nothing" */
1225                         return;
1226
1227                 if (newtuple != tuple)  /* modified by Trigger(s) */
1228                 {
1229                         /*
1230                          * Insert modified tuple into tuple table slot, replacing the
1231                          * original.  We assume that it was allocated in per-tuple
1232                          * memory context, and therefore will go away by itself.
1233                          * The tuple table slot should not try to clear it.
1234                          */
1235                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1236                         tuple = newtuple;
1237                 }
1238         }
1239
1240         /*
1241          * Check the constraints of the tuple
1242          */
1243         if (resultRelationDesc->rd_att->constr)
1244                 ExecConstraints("ExecAppend", resultRelInfo, slot, estate);
1245
1246         /*
1247          * insert the tuple
1248          */
1249         newId = heap_insert(resultRelationDesc, tuple);
1250
1251         IncrAppended();
1252         (estate->es_processed)++;
1253         estate->es_lastoid = newId;
1254
1255         /*
1256          * process indices
1257          *
1258          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1259          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1260          * field.
1261          */
1262         numIndices = resultRelInfo->ri_NumIndices;
1263         if (numIndices > 0)
1264                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1265
1266         /* AFTER ROW INSERT Triggers */
1267         if (resultRelationDesc->trigdesc)
1268                 ExecARInsertTriggers(estate, resultRelationDesc, tuple);
1269 }
1270
1271 /* ----------------------------------------------------------------
1272  *              ExecDelete
1273  *
1274  *              DELETE is like append, we delete the tuple and its
1275  *              index tuples.
1276  * ----------------------------------------------------------------
1277  */
1278 static void
1279 ExecDelete(TupleTableSlot *slot,
1280                    ItemPointer tupleid,
1281                    EState *estate)
1282 {
1283         ResultRelInfo *resultRelInfo;
1284         Relation        resultRelationDesc;
1285         ItemPointerData ctid;
1286         int                     result;
1287
1288         /*
1289          * get information on the (current) result relation
1290          */
1291         resultRelInfo = estate->es_result_relation_info;
1292         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1293
1294         /* BEFORE ROW DELETE Triggers */
1295         if (resultRelationDesc->trigdesc &&
1296                 resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1297         {
1298                 bool            dodelete;
1299
1300                 dodelete = ExecBRDeleteTriggers(estate, tupleid);
1301
1302                 if (!dodelete)                  /* "do nothing" */
1303                         return;
1304         }
1305
1306         /*
1307          * delete the tuple
1308          */
1309 ldelete:;
1310         result = heap_delete(resultRelationDesc, tupleid, &ctid);
1311         switch (result)
1312         {
1313                 case HeapTupleSelfUpdated:
1314                         return;
1315
1316                 case HeapTupleMayBeUpdated:
1317                         break;
1318
1319                 case HeapTupleUpdated:
1320                         if (XactIsoLevel == XACT_SERIALIZABLE)
1321                                 elog(ERROR, "Can't serialize access due to concurrent update");
1322                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1323                         {
1324                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1325                                                   resultRelInfo->ri_RangeTableIndex, &ctid);
1326
1327                                 if (!TupIsNull(epqslot))
1328                                 {
1329                                         *tupleid = ctid;
1330                                         goto ldelete;
1331                                 }
1332                         }
1333                         return;
1334
1335                 default:
1336                         elog(ERROR, "Unknown status %u from heap_delete", result);
1337                         return;
1338         }
1339
1340         IncrDeleted();
1341         (estate->es_processed)++;
1342
1343         /*
1344          * Note: Normally one would think that we have to delete index tuples
1345          * associated with the heap tuple now..
1346          *
1347          * ... but in POSTGRES, we have no need to do this because the vacuum
1348          * daemon automatically opens an index scan and deletes index tuples
1349          * when it finds deleted heap tuples. -cim 9/27/89
1350          */
1351
1352         /* AFTER ROW DELETE Triggers */
1353         if (resultRelationDesc->trigdesc)
1354                 ExecARDeleteTriggers(estate, tupleid);
1355 }
1356
1357 /* ----------------------------------------------------------------
1358  *              ExecReplace
1359  *
1360  *              note: we can't run replace queries with transactions
1361  *              off because replaces are actually appends and our
1362  *              scan will mistakenly loop forever, replacing the tuple
1363  *              it just appended..      This should be fixed but until it
1364  *              is, we don't want to get stuck in an infinite loop
1365  *              which corrupts your database..
1366  * ----------------------------------------------------------------
1367  */
1368 static void
1369 ExecReplace(TupleTableSlot *slot,
1370                         ItemPointer tupleid,
1371                         EState *estate)
1372 {
1373         HeapTuple       tuple;
1374         ResultRelInfo *resultRelInfo;
1375         Relation        resultRelationDesc;
1376         ItemPointerData ctid;
1377         int                     result;
1378         int                     numIndices;
1379
1380         /*
1381          * abort the operation if not running transactions
1382          */
1383         if (IsBootstrapProcessingMode())
1384         {
1385                 elog(NOTICE, "ExecReplace: replace can't run without transactions");
1386                 return;
1387         }
1388
1389         /*
1390          * get the heap tuple out of the tuple table slot
1391          */
1392         tuple = slot->val;
1393
1394         /*
1395          * get information on the (current) result relation
1396          */
1397         resultRelInfo = estate->es_result_relation_info;
1398         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1399
1400         /* BEFORE ROW UPDATE Triggers */
1401         if (resultRelationDesc->trigdesc &&
1402                 resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1403         {
1404                 HeapTuple       newtuple;
1405
1406                 newtuple = ExecBRUpdateTriggers(estate, tupleid, tuple);
1407
1408                 if (newtuple == NULL)   /* "do nothing" */
1409                         return;
1410
1411                 if (newtuple != tuple)  /* modified by Trigger(s) */
1412                 {
1413                         /*
1414                          * Insert modified tuple into tuple table slot, replacing the
1415                          * original.  We assume that it was allocated in per-tuple
1416                          * memory context, and therefore will go away by itself.
1417                          * The tuple table slot should not try to clear it.
1418                          */
1419                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1420                         tuple = newtuple;
1421                 }
1422         }
1423
1424         /*
1425          * Check the constraints of the tuple
1426          */
1427         if (resultRelationDesc->rd_att->constr)
1428                 ExecConstraints("ExecReplace", resultRelInfo, slot, estate);
1429
1430         /*
1431          * replace the heap tuple
1432          */
1433 lreplace:;
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, slot, InvalidBuffer, true);
1456                                         goto lreplace;
1457                                 }
1458                         }
1459                         return;
1460
1461                 default:
1462                         elog(ERROR, "Unknown status %u from heap_update", result);
1463                         return;
1464         }
1465
1466         IncrReplaced();
1467         (estate->es_processed)++;
1468
1469         /*
1470          * Note: instead of having to update the old index tuples associated
1471          * with the heap tuple, all we do is form and insert new index
1472          * tuples.  This is because replaces are actually deletes and inserts
1473          * and index tuple deletion is done automagically by the vacuum
1474          * daemon. All we do is insert new index tuples.  -cim 9/27/89
1475          */
1476
1477         /*
1478          * process indices
1479          *
1480          * heap_update updates a tuple in the base relation by invalidating it
1481          * and then appending a new tuple to the relation.      As a side effect,
1482          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1483          * field.  So we now insert index tuples using the new tupleid stored
1484          * there.
1485          */
1486
1487         numIndices = resultRelInfo->ri_NumIndices;
1488         if (numIndices > 0)
1489                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
1490
1491         /* AFTER ROW UPDATE Triggers */
1492         if (resultRelationDesc->trigdesc)
1493                 ExecARUpdateTriggers(estate, tupleid, tuple);
1494 }
1495
1496 static char *
1497 ExecRelCheck(ResultRelInfo *resultRelInfo,
1498                          TupleTableSlot *slot, EState *estate)
1499 {
1500         Relation        rel = resultRelInfo->ri_RelationDesc;
1501         int                     ncheck = rel->rd_att->constr->num_check;
1502         ConstrCheck *check = rel->rd_att->constr->check;
1503         ExprContext *econtext;
1504         MemoryContext oldContext;
1505         List       *qual;
1506         int                     i;
1507
1508         /*
1509          * If first time through for this result relation, build expression
1510          * nodetrees for rel's constraint expressions.  Keep them in the
1511          * per-query memory context so they'll survive throughout the query.
1512          */
1513         if (resultRelInfo->ri_ConstraintExprs == NULL)
1514         {
1515                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1516                 resultRelInfo->ri_ConstraintExprs =
1517                         (List **) palloc(ncheck * sizeof(List *));
1518                 for (i = 0; i < ncheck; i++)
1519                 {
1520                         qual = (List *) stringToNode(check[i].ccbin);
1521                         resultRelInfo->ri_ConstraintExprs[i] = qual;
1522                 }
1523                 MemoryContextSwitchTo(oldContext);
1524         }
1525
1526         /*
1527          * We will use the EState's per-tuple context for evaluating constraint
1528          * expressions (creating it if it's not already there).
1529          */
1530         econtext = GetPerTupleExprContext(estate);
1531
1532         /* Arrange for econtext's scan tuple to be the tuple under test */
1533         econtext->ecxt_scantuple = slot;
1534
1535         /* And evaluate the constraints */
1536         for (i = 0; i < ncheck; i++)
1537         {
1538                 qual = resultRelInfo->ri_ConstraintExprs[i];
1539
1540                 /*
1541                  * NOTE: SQL92 specifies that a NULL result from a constraint
1542                  * expression is not to be treated as a failure.  Therefore, tell
1543                  * ExecQual to return TRUE for NULL.
1544                  */
1545                 if (!ExecQual(qual, econtext, true))
1546                         return check[i].ccname;
1547         }
1548
1549         /* NULL result means no error */
1550         return (char *) NULL;
1551 }
1552
1553 void
1554 ExecConstraints(char *caller, ResultRelInfo *resultRelInfo,
1555                                 TupleTableSlot *slot, EState *estate)
1556 {
1557         Relation        rel = resultRelInfo->ri_RelationDesc;
1558         HeapTuple       tuple = slot->val;
1559         TupleConstr *constr = rel->rd_att->constr;
1560
1561         Assert(constr);
1562
1563         if (constr->has_not_null)
1564         {
1565                 int                     natts = rel->rd_att->natts;
1566                 int                     attrChk;
1567
1568                 for (attrChk = 1; attrChk <= natts; attrChk++)
1569                 {
1570                         if (rel->rd_att->attrs[attrChk-1]->attnotnull &&
1571                                 heap_attisnull(tuple, attrChk))
1572                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1573                                          caller, NameStr(rel->rd_att->attrs[attrChk-1]->attname));
1574                 }
1575         }
1576
1577         if (constr->num_check > 0)
1578         {
1579                 char       *failed;
1580
1581                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1582                         elog(ERROR, "%s: rejected due to CHECK constraint %s",
1583                                  caller, failed);
1584         }
1585 }
1586
1587 TupleTableSlot *
1588 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1589 {
1590         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1591         evalPlanQual *oldepq;
1592         EState     *epqstate = NULL;
1593         Relation        relation;
1594         Buffer          buffer;
1595         HeapTupleData tuple;
1596         bool            endNode = true;
1597
1598         Assert(rti != 0);
1599
1600         if (epq != NULL && epq->rti == 0)
1601         {
1602                 Assert(!(estate->es_useEvalPlan) &&
1603                            epq->estate.es_evalPlanQual == NULL);
1604                 epq->rti = rti;
1605                 endNode = false;
1606         }
1607
1608         /*
1609          * If this is request for another RTE - Ra, - then we have to check
1610          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1611          * updated again and we have to re-start old execution for Ra and
1612          * forget all what we done after Ra was suspended. Cool? -:))
1613          */
1614         if (epq != NULL && epq->rti != rti &&
1615                 epq->estate.es_evTuple[rti - 1] != NULL)
1616         {
1617                 do
1618                 {
1619                         /* pop previous PlanQual from the stack */
1620                         epqstate = &(epq->estate);
1621                         oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1622                         Assert(oldepq->rti != 0);
1623                         /* stop execution */
1624                         ExecEndNode(epq->plan, epq->plan);
1625                         epqstate->es_tupleTable->next = 0;
1626                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1627                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1628                         /* push current PQ to freePQ stack */
1629                         oldepq->free = epq;
1630                         epq = oldepq;
1631                 } while (epq->rti != rti);
1632                 estate->es_evalPlanQual = (Pointer) epq;
1633         }
1634
1635         /*
1636          * If we are requested for another RTE then we have to suspend
1637          * execution of current PlanQual and start execution for new one.
1638          */
1639         if (epq == NULL || epq->rti != rti)
1640         {
1641                 /* try to reuse plan used previously */
1642                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1643
1644                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1645                 {
1646                         newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1647                         /* Init EState */
1648                         epqstate = &(newepq->estate);
1649                         memset(epqstate, 0, sizeof(EState));
1650                         epqstate->type = T_EState;
1651                         epqstate->es_direction = ForwardScanDirection;
1652                         epqstate->es_snapshot = estate->es_snapshot;
1653                         epqstate->es_range_table = estate->es_range_table;
1654                         epqstate->es_param_list_info = estate->es_param_list_info;
1655                         if (estate->es_origPlan->nParamExec > 0)
1656                                 epqstate->es_param_exec_vals = (ParamExecData *)
1657                                         palloc(estate->es_origPlan->nParamExec *
1658                                                    sizeof(ParamExecData));
1659                         epqstate->es_tupleTable =
1660                                 ExecCreateTupleTable(estate->es_tupleTable->size);
1661                         /* ... rest */
1662                         newepq->plan = copyObject(estate->es_origPlan);
1663                         newepq->free = NULL;
1664                         epqstate->es_evTupleNull = (bool *)
1665                                 palloc(length(estate->es_range_table) * sizeof(bool));
1666                         if (epq == NULL)        /* first call */
1667                         {
1668                                 epqstate->es_evTuple = (HeapTuple *)
1669                                         palloc(length(estate->es_range_table) * sizeof(HeapTuple));
1670                                 memset(epqstate->es_evTuple, 0,
1671                                          length(estate->es_range_table) * sizeof(HeapTuple));
1672                         }
1673                         else
1674                                 epqstate->es_evTuple = epq->estate.es_evTuple;
1675                 }
1676                 else
1677                         epqstate = &(newepq->estate);
1678                 /* push current PQ to the stack */
1679                 epqstate->es_evalPlanQual = (Pointer) epq;
1680                 epq = newepq;
1681                 estate->es_evalPlanQual = (Pointer) epq;
1682                 epq->rti = rti;
1683                 endNode = false;
1684         }
1685
1686         epqstate = &(epq->estate);
1687
1688         /*
1689          * Ok - we're requested for the same RTE (-:)). I'm not sure about
1690          * ability to use ExecReScan instead of ExecInitNode, so...
1691          */
1692         if (endNode)
1693         {
1694                 ExecEndNode(epq->plan, epq->plan);
1695                 epqstate->es_tupleTable->next = 0;
1696         }
1697
1698         /* free old RTE' tuple */
1699         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1700         {
1701                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1702                 epqstate->es_evTuple[epq->rti - 1] = NULL;
1703         }
1704
1705         /* ** fetch tid tuple ** */
1706         if (estate->es_result_relation_info != NULL &&
1707                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1708                 relation = estate->es_result_relation_info->ri_RelationDesc;
1709         else
1710         {
1711                 List       *l;
1712
1713                 foreach(l, estate->es_rowMark)
1714                 {
1715                         if (((execRowMark *) lfirst(l))->rti == rti)
1716                                 break;
1717                 }
1718                 relation = ((execRowMark *) lfirst(l))->relation;
1719         }
1720         tuple.t_self = *tid;
1721         for (;;)
1722         {
1723                 heap_fetch(relation, SnapshotDirty, &tuple, &buffer);
1724                 if (tuple.t_data != NULL)
1725                 {
1726                         TransactionId xwait = SnapshotDirty->xmax;
1727
1728                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1729                         {
1730                                 elog(NOTICE, "EvalPlanQual: t_xmin is uncommitted ?!");
1731                                 Assert(!TransactionIdIsValid(SnapshotDirty->xmin));
1732                                 elog(ERROR, "Aborting this transaction");
1733                         }
1734
1735                         /*
1736                          * If tuple is being updated by other transaction then we have
1737                          * to wait for its commit/abort.
1738                          */
1739                         if (TransactionIdIsValid(xwait))
1740                         {
1741                                 ReleaseBuffer(buffer);
1742                                 XactLockTableWait(xwait);
1743                                 continue;
1744                         }
1745
1746                         /*
1747                          * Nice! We got tuple - now copy it.
1748                          */
1749                         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1750                                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1751                         epqstate->es_evTuple[epq->rti - 1] = heap_copytuple(&tuple);
1752                         ReleaseBuffer(buffer);
1753                         break;
1754                 }
1755
1756                 /*
1757                  * Ops! Invalid tuple. Have to check is it updated or deleted.
1758                  * Note that it's possible to get invalid SnapshotDirty->tid if
1759                  * tuple updated by this transaction. Have we to check this ?
1760                  */
1761                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1762                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1763                 {
1764                         tuple.t_self = SnapshotDirty->tid;      /* updated ... */
1765                         continue;
1766                 }
1767
1768                 /*
1769                  * Deleted or updated by this transaction. Do not (re-)start
1770                  * execution of this PQ. Continue previous PQ.
1771                  */
1772                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1773                 if (oldepq != NULL)
1774                 {
1775                         Assert(oldepq->rti != 0);
1776                         /* push current PQ to freePQ stack */
1777                         oldepq->free = epq;
1778                         epq = oldepq;
1779                         epqstate = &(epq->estate);
1780                         estate->es_evalPlanQual = (Pointer) epq;
1781                 }
1782                 else
1783                 {
1784                         epq->rti = 0;           /* this is the first (oldest) */
1785                         estate->es_useEvalPlan = false;         /* PQ - mark as free and          */
1786                         return (NULL);          /* continue Query execution   */
1787                 }
1788         }
1789
1790         if (estate->es_origPlan->nParamExec > 0)
1791                 memset(epqstate->es_param_exec_vals, 0,
1792                            estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1793         memset(epqstate->es_evTupleNull, false,
1794                    length(estate->es_range_table) * sizeof(bool));
1795         Assert(epqstate->es_tupleTable->next == 0);
1796         ExecInitNode(epq->plan, epqstate, NULL);
1797
1798         /*
1799          * For UPDATE/DELETE we have to return tid of actual row we're
1800          * executing PQ for.
1801          */
1802         *tid = tuple.t_self;
1803
1804         return EvalPlanQualNext(estate);
1805 }
1806
1807 static TupleTableSlot *
1808 EvalPlanQualNext(EState *estate)
1809 {
1810         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1811         EState     *epqstate = &(epq->estate);
1812         evalPlanQual *oldepq;
1813         TupleTableSlot *slot;
1814
1815         Assert(epq->rti != 0);
1816
1817 lpqnext:;
1818         slot = ExecProcNode(epq->plan, epq->plan);
1819
1820         /*
1821          * No more tuples for this PQ. Continue previous one.
1822          */
1823         if (TupIsNull(slot))
1824         {
1825                 ExecEndNode(epq->plan, epq->plan);
1826                 epqstate->es_tupleTable->next = 0;
1827                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1828                 epqstate->es_evTuple[epq->rti - 1] = NULL;
1829                 /* pop old PQ from the stack */
1830                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1831                 if (oldepq == (evalPlanQual *) NULL)
1832                 {
1833                         epq->rti = 0;           /* this is the first (oldest) */
1834                         estate->es_useEvalPlan = false;         /* PQ - mark as free and          */
1835                         return (NULL);          /* continue Query execution   */
1836                 }
1837                 Assert(oldepq->rti != 0);
1838                 /* push current PQ to freePQ stack */
1839                 oldepq->free = epq;
1840                 epq = oldepq;
1841                 epqstate = &(epq->estate);
1842                 estate->es_evalPlanQual = (Pointer) epq;
1843                 goto lpqnext;
1844         }
1845
1846         return (slot);
1847 }
1848
1849 static void
1850 EndEvalPlanQual(EState *estate)
1851 {
1852         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1853         EState     *epqstate = &(epq->estate);
1854         evalPlanQual *oldepq;
1855
1856         if (epq->rti == 0)                      /* plans already shutdowned */
1857         {
1858                 Assert(epq->estate.es_evalPlanQual == NULL);
1859                 return;
1860         }
1861
1862         for (;;)
1863         {
1864                 ExecEndNode(epq->plan, epq->plan);
1865                 epqstate->es_tupleTable->next = 0;
1866                 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1867                 {
1868                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1869                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1870                 }
1871                 /* pop old PQ from the stack */
1872                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1873                 if (oldepq == (evalPlanQual *) NULL)
1874                 {
1875                         epq->rti = 0;           /* this is the first (oldest) */
1876                         estate->es_useEvalPlan = false;         /* PQ - mark as free */
1877                         break;
1878                 }
1879                 Assert(oldepq->rti != 0);
1880                 /* push current PQ to freePQ stack */
1881                 oldepq->free = epq;
1882                 epq = oldepq;
1883                 epqstate = &(epq->estate);
1884                 estate->es_evalPlanQual = (Pointer) epq;
1885         }
1886 }