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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 1.139 2001/03/22 03:59:26 momjian Exp $
  31  *
  32  *-------------------------------------------------------------------------
  33  */
  34 #include "postgres.h"
  35
  36 #include "access/heapam.h"
  37 #include "catalog/heap.h"
  38 #include "commands/command.h"
  39 #include "commands/trigger.h"
  40 #include "executor/execdebug.h"
  41 #include "executor/execdefs.h"
  42 #include "miscadmin.h"
  43 #include "optimizer/var.h"
  44 #include "parser/parsetree.h"
  45 #include "utils/acl.h"
  46
  47
  48 /* decls for local routines only used within this module */
  49 static TupleDesc InitPlan(CmdType operation,
  50                  Query *parseTree,
  51                  Plan *plan,
  52                  EState *estate);
  53 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  54                                   Index resultRelationIndex,
  55                                   List *rangeTable,
  56                                   CmdType operation);
  57 static void EndPlan(Plan *plan, EState *estate);
  58 static TupleTableSlot *ExecutePlan(EState *estate, Plan *plan,
  59                         CmdType operation,
  60                         long numberTuples,
  61                         ScanDirection direction,
  62                         DestReceiver *destfunc);
  63 static void ExecRetrieve(TupleTableSlot *slot,
  64                          DestReceiver *destfunc,
  65                          EState *estate);
  66 static void ExecAppend(TupleTableSlot *slot, ItemPointer tupleid,
  67                    EState *estate);
  68 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  69                    EState *estate);
  70 static void ExecReplace(TupleTableSlot *slot, ItemPointer tupleid,
  71                         EState *estate);
  72 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  73 static void EndEvalPlanQual(EState *estate);
  74 static void ExecCheckQueryPerms(CmdType operation, Query *parseTree,
  75                                         Plan *plan);
  76 static void ExecCheckPlanPerms(Plan *plan, List *rangeTable,
  77                                    CmdType operation);
  78 static void ExecCheckRTPerms(List *rangeTable, CmdType operation);
  79 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
  80
  81 /* end of local decls */
  82
  83
  84 /* ----------------------------------------------------------------
  85  *              ExecutorStart
  86  *
  87  *              This routine must be called at the beginning of any execution of any
  88  *              query plan
  89  *
  90  *              returns a TupleDesc which describes the attributes of the tuples to
  91  *              be returned by the query.
  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 execution of any
 256  *              query plan
 257  * ----------------------------------------------------------------
 258  */
 259 void
 260 ExecutorEnd(QueryDesc *queryDesc, EState *estate)
 261 {
 262         /* sanity checks */
 263         Assert(queryDesc != NULL);
 264
 265         EndPlan(queryDesc->plantree, estate);
 266
 267         if (estate->es_snapshot != NULL)
 268         {
 269                 if (estate->es_snapshot->xcnt > 0)
 270                         pfree(estate->es_snapshot->xip);
 271                 pfree(estate->es_snapshot);
 272                 estate->es_snapshot = NULL;
 273         }
 274
 275         if (estate->es_param_exec_vals != NULL)
 276         {
 277                 pfree(estate->es_param_exec_vals);
 278                 estate->es_param_exec_vals = NULL;
 279         }
 280 }
 281
 282
 283 /*
 284  * ExecCheckQueryPerms
 285  *              Check access permissions for all relations referenced in a query.
 286  */
 287 static void
 288 ExecCheckQueryPerms(CmdType operation, Query *parseTree, Plan *plan)
 289 {
 290
 291         /*
 292          * Check RTEs in the query's primary rangetable.
 293          */
 294         ExecCheckRTPerms(parseTree->rtable, operation);
 295
 296         /*
 297          * Search for subplans and APPEND nodes to check their rangetables.
 298          */
 299         ExecCheckPlanPerms(plan, parseTree->rtable, operation);
 300 }
 301
 302 /*
 303  * ExecCheckPlanPerms
 304  *              Recursively scan the plan tree to check access permissions in
 305  *              subplans.
 306  */
 307 static void
 308 ExecCheckPlanPerms(Plan *plan, List *rangeTable, CmdType operation)
 309 {
 310         List       *subp;
 311
 312         if (plan == NULL)
 313                 return;
 314
 315         /* Check subplans, which we assume are plain SELECT queries */
 316
 317         foreach(subp, plan->initPlan)
 318         {
 319                 SubPlan    *subplan = (SubPlan *) lfirst(subp);
 320
 321                 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 322                 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
 323         }
 324         foreach(subp, plan->subPlan)
 325         {
 326                 SubPlan    *subplan = (SubPlan *) lfirst(subp);
 327
 328                 ExecCheckRTPerms(subplan->rtable, CMD_SELECT);
 329                 ExecCheckPlanPerms(subplan->plan, subplan->rtable, CMD_SELECT);
 330         }
 331
 332         /* Check lower plan nodes */
 333
 334         ExecCheckPlanPerms(plan->lefttree, rangeTable, operation);
 335         ExecCheckPlanPerms(plan->righttree, rangeTable, operation);
 336
 337         /* Do node-type-specific checks */
 338
 339         switch (nodeTag(plan))
 340         {
 341                 case T_SubqueryScan:
 342                         {
 343                                 SubqueryScan *scan = (SubqueryScan *) plan;
 344                                 RangeTblEntry *rte;
 345
 346                                 /* Recursively check the subquery */
 347                                 rte = rt_fetch(scan->scan.scanrelid, rangeTable);
 348                                 Assert(rte->subquery != NULL);
 349                                 ExecCheckQueryPerms(operation, rte->subquery, scan->subplan);
 350                                 break;
 351                         }
 352                 case T_Append:
 353                         {
 354                                 Append     *app = (Append *) plan;
 355                                 List       *appendplans;
 356
 357                                 foreach(appendplans, app->appendplans)
 358                                 {
 359                                         ExecCheckPlanPerms((Plan *) lfirst(appendplans),
 360                                                                            rangeTable,
 361                                                                            operation);
 362                                 }
 363                                 break;
 364                         }
 365
 366                 default:
 367                         break;
 368         }
 369 }
 370
 371 /*
 372  * ExecCheckRTPerms
 373  *              Check access permissions for all relations listed in a range table.
 374  */
 375 static void
 376 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 377 {
 378         List       *lp;
 379
 380         foreach(lp, rangeTable)
 381         {
 382                 RangeTblEntry *rte = lfirst(lp);
 383
 384                 ExecCheckRTEPerms(rte, operation);
 385         }
 386 }
 387
 388 /*
 389  * ExecCheckRTEPerms
 390  *              Check access permissions for a single RTE.
 391  */
 392 static void
 393 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 394 {
 395         char       *relName;
 396         Oid                     userid;
 397         int32           aclcheck_result;
 398
 399         /*
 400          * If it's a subquery RTE, ignore it --- it will be checked when
 401          * ExecCheckPlanPerms finds the SubqueryScan node for it.
 402          */
 403         if (rte->subquery)
 404                 return;
 405
 406         relName = rte->relname;
 407
 408         /*
 409          * userid to check as: current user unless we have a setuid
 410          * indication.
 411          *
 412          * Note: GetUserId() is presently fast enough that there's no harm in
 413          * calling it separately for each RTE.  If that stops being true, we
 414          * could call it once in ExecCheckQueryPerms and pass the userid down
 415          * from there.  But for now, no need for the extra clutter.
 416          */
 417         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 418
 419 #define CHECK(MODE)             pg_aclcheck(relName, userid, MODE)
 420
 421         if (rte->checkForRead)
 422         {
 423                 aclcheck_result = CHECK(ACL_RD);
 424                 if (aclcheck_result != ACLCHECK_OK)
 425                         elog(ERROR, "%s: %s",
 426                                  relName, aclcheck_error_strings[aclcheck_result]);
 427         }
 428
 429         if (rte->checkForWrite)
 430         {
 431
 432                 /*
 433                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 434                  * Right now we don't distinguish that from true update as far as
 435                  * permissions checks are concerned.
 436                  */
 437                 switch (operation)
 438                 {
 439                         case CMD_INSERT:
 440                                 /* Accept either APPEND or WRITE access for this */
 441                                 aclcheck_result = CHECK(ACL_AP);
 442                                 if (aclcheck_result != ACLCHECK_OK)
 443                                         aclcheck_result = CHECK(ACL_WR);
 444                                 break;
 445                         case CMD_SELECT:
 446                         case CMD_DELETE:
 447                         case CMD_UPDATE:
 448                                 aclcheck_result = CHECK(ACL_WR);
 449                                 break;
 450                         default:
 451                                 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
 452                                          operation);
 453                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 454                                 break;
 455                 }
 456                 if (aclcheck_result != ACLCHECK_OK)
 457                         elog(ERROR, "%s: %s",
 458                                  relName, aclcheck_error_strings[aclcheck_result]);
 459         }
 460 }
 461
 462
 463 /* ===============================================================
 464  * ===============================================================
 465                                                  static routines follow
 466  * ===============================================================
 467  * ===============================================================
 468  */
 469
 470 typedef struct execRowMark
 471 {
 472         Relation        relation;
 473         Index           rti;
 474         char            resname[32];
 475 } execRowMark;
 476
 477 typedef struct evalPlanQual
 478 {
 479         Plan       *plan;
 480         Index           rti;
 481         EState          estate;
 482         struct evalPlanQual *free;
 483 } evalPlanQual;
 484
 485 /* ----------------------------------------------------------------
 486  *              InitPlan
 487  *
 488  *              Initializes the query plan: open files, allocate storage
 489  *              and start up the rule manager
 490  * ----------------------------------------------------------------
 491  */
 492 static TupleDesc
 493 InitPlan(CmdType operation, Query *parseTree, Plan *plan, EState *estate)
 494 {
 495         List       *rangeTable;
 496         Relation        intoRelationDesc;
 497         TupleDesc       tupType;
 498
 499         /*
 500          * Do permissions checks.
 501          */
 502         ExecCheckQueryPerms(operation, parseTree, plan);
 503
 504         /*
 505          * get information from query descriptor
 506          */
 507         rangeTable = parseTree->rtable;
 508
 509         /*
 510          * initialize the node's execution state
 511          */
 512         estate->es_range_table = rangeTable;
 513
 514         /*
 515          * if there is a result relation, initialize result relation stuff
 516          */
 517         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 518         {
 519                 List       *resultRelations = parseTree->resultRelations;
 520                 int                     numResultRelations;
 521                 ResultRelInfo *resultRelInfos;
 522
 523                 if (resultRelations != NIL)
 524                 {
 525
 526                         /*
 527                          * Multiple result relations (due to inheritance)
 528                          * parseTree->resultRelations identifies them all
 529                          */
 530                         ResultRelInfo *resultRelInfo;
 531
 532                         numResultRelations = length(resultRelations);
 533                         resultRelInfos = (ResultRelInfo *)
 534                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 535                         resultRelInfo = resultRelInfos;
 536                         while (resultRelations != NIL)
 537                         {
 538                                 initResultRelInfo(resultRelInfo,
 539                                                                   lfirsti(resultRelations),
 540                                                                   rangeTable,
 541                                                                   operation);
 542                                 resultRelInfo++;
 543                                 resultRelations = lnext(resultRelations);
 544                         }
 545                 }
 546                 else
 547                 {
 548
 549                         /*
 550                          * Single result relation identified by
 551                          * parseTree->resultRelation
 552                          */
 553                         numResultRelations = 1;
 554                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 555                         initResultRelInfo(resultRelInfos,
 556                                                           parseTree->resultRelation,
 557                                                           rangeTable,
 558                                                           operation);
 559                 }
 560
 561                 estate->es_result_relations = resultRelInfos;
 562                 estate->es_num_result_relations = numResultRelations;
 563                 /* Initialize to first or only result rel */
 564                 estate->es_result_relation_info = resultRelInfos;
 565         }
 566         else
 567         {
 568
 569                 /*
 570                  * if no result relation, then set state appropriately
 571                  */
 572                 estate->es_result_relations = NULL;
 573                 estate->es_num_result_relations = 0;
 574                 estate->es_result_relation_info = NULL;
 575         }
 576
 577         /*
 578          * Have to lock relations selected for update
 579          */
 580         estate->es_rowMark = NIL;
 581         if (parseTree->rowMarks != NIL)
 582         {
 583                 List       *l;
 584
 585                 foreach(l, parseTree->rowMarks)
 586                 {
 587                         Index           rti = lfirsti(l);
 588                         Oid                     relid = getrelid(rti, rangeTable);
 589                         Relation        relation;
 590                         execRowMark *erm;
 591
 592                         relation = heap_open(relid, RowShareLock);
 593                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 594                         erm->relation = relation;
 595                         erm->rti = rti;
 596                         sprintf(erm->resname, "ctid%u", rti);
 597                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 598                 }
 599         }
 600
 601         /*
 602          * initialize the executor "tuple" table.
 603          */
 604         {
 605                 int                     nSlots = ExecCountSlotsNode(plan);
 606                 TupleTable      tupleTable = ExecCreateTupleTable(nSlots + 10);         /* why add ten? - jolly */
 607
 608                 estate->es_tupleTable = tupleTable;
 609         }
 610
 611         /*
 612          * initialize the private state information for all the nodes in the
 613          * query tree.  This opens files, allocates storage and leaves us
 614          * ready to start processing tuples.
 615          */
 616         ExecInitNode(plan, estate, NULL);
 617
 618         /*
 619          * Get the tuple descriptor describing the type of tuples to return.
 620          * (this is especially important if we are creating a relation with
 621          * "retrieve into")
 622          */
 623         tupType = ExecGetTupType(plan);         /* tuple descriptor */
 624
 625         /*
 626          * Initialize the junk filter if needed. SELECT and INSERT queries
 627          * need a filter if there are any junk attrs in the tlist.      UPDATE and
 628          * DELETE always need one, since there's always a junk 'ctid'
 629          * attribute present --- no need to look first.
 630          */
 631         {
 632                 bool            junk_filter_needed = false;
 633                 List       *tlist;
 634
 635                 switch (operation)
 636                 {
 637                         case CMD_SELECT:
 638                         case CMD_INSERT:
 639                                 foreach(tlist, plan->targetlist)
 640                                 {
 641                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 642
 643                                         if (tle->resdom->resjunk)
 644                                         {
 645                                                 junk_filter_needed = true;
 646                                                 break;
 647                                         }
 648                                 }
 649                                 break;
 650                         case CMD_UPDATE:
 651                         case CMD_DELETE:
 652                                 junk_filter_needed = true;
 653                                 break;
 654                         default:
 655                                 break;
 656                 }
 657
 658                 if (junk_filter_needed)
 659                 {
 660
 661                         /*
 662                          * If there are multiple result relations, each one needs its
 663                          * own junk filter.  Note this is only possible for
 664                          * UPDATE/DELETE, so we can't be fooled by some needing a
 665                          * filter and some not.
 666                          */
 667                         if (parseTree->resultRelations != NIL)
 668                         {
 669                                 List       *subplans;
 670                                 ResultRelInfo *resultRelInfo;
 671
 672                                 /* Top plan had better be an Append here. */
 673                                 Assert(IsA(plan, Append));
 674                                 Assert(((Append *) plan)->isTarget);
 675                                 subplans = ((Append *) plan)->appendplans;
 676                                 Assert(length(subplans) == estate->es_num_result_relations);
 677                                 resultRelInfo = estate->es_result_relations;
 678                                 while (subplans != NIL)
 679                                 {
 680                                         Plan       *subplan = (Plan *) lfirst(subplans);
 681                                         JunkFilter *j;
 682
 683                                         j = ExecInitJunkFilter(subplan->targetlist,
 684                                                                                    ExecGetTupType(subplan));
 685                                         resultRelInfo->ri_junkFilter = j;
 686                                         resultRelInfo++;
 687                                         subplans = lnext(subplans);
 688                                 }
 689
 690                                 /*
 691                                  * Set active junkfilter too; at this point ExecInitAppend
 692                                  * has already selected an active result relation...
 693                                  */
 694                                 estate->es_junkFilter =
 695                                         estate->es_result_relation_info->ri_junkFilter;
 696                         }
 697                         else
 698                         {
 699                                 /* Normal case with just one JunkFilter */
 700                                 JunkFilter *j = ExecInitJunkFilter(plan->targetlist,
 701                                                                                                    tupType);
 702
 703                                 estate->es_junkFilter = j;
 704                                 if (estate->es_result_relation_info)
 705                                         estate->es_result_relation_info->ri_junkFilter = j;
 706
 707                                 /* For SELECT, want to return the cleaned tuple type */
 708                                 if (operation == CMD_SELECT)
 709                                         tupType = j->jf_cleanTupType;
 710                         }
 711                 }
 712                 else
 713                         estate->es_junkFilter = NULL;
 714         }
 715
 716         /*
 717          * initialize the "into" relation
 718          */
 719         intoRelationDesc = (Relation) NULL;
 720
 721         if (operation == CMD_SELECT)
 722         {
 723                 char       *intoName;
 724                 Oid                     intoRelationId;
 725                 TupleDesc       tupdesc;
 726
 727                 if (!parseTree->isPortal)
 728                 {
 729
 730                         /*
 731                          * a select into table
 732                          */
 733                         if (parseTree->into != NULL)
 734                         {
 735
 736                                 /*
 737                                  * create the "into" relation
 738                                  */
 739                                 intoName = parseTree->into;
 740
 741                                 /*
 742                                  * have to copy tupType to get rid of constraints
 743                                  */
 744                                 tupdesc = CreateTupleDescCopy(tupType);
 745
 746                                 intoRelationId =
 747                                         heap_create_with_catalog(intoName,
 748                                                                                          tupdesc,
 749                                                                                          RELKIND_RELATION,
 750                                                                                          parseTree->isTemp,
 751                                                                                          allowSystemTableMods);
 752
 753                                 FreeTupleDesc(tupdesc);
 754
 755                                 /*
 756                                  * Advance command counter so that the newly-created
 757                                  * relation's catalog tuples will be visible to heap_open.
 758                                  */
 759                                 CommandCounterIncrement();
 760
 761                                 /*
 762                                  * If necessary, create a TOAST table for the into
 763                                  * relation. Note that AlterTableCreateToastTable ends
 764                                  * with CommandCounterIncrement(), so that the TOAST table
 765                                  * will be visible for insertion.
 766                                  */
 767                                 AlterTableCreateToastTable(intoName, true);
 768
 769                                 intoRelationDesc = heap_open(intoRelationId,
 770                                                                                          AccessExclusiveLock);
 771                         }
 772                 }
 773         }
 774
 775         estate->es_into_relation_descriptor = intoRelationDesc;
 776
 777         estate->es_origPlan = plan;
 778         estate->es_evalPlanQual = NULL;
 779         estate->es_evTuple = NULL;
 780         estate->es_useEvalPlan = false;
 781
 782         return tupType;
 783 }
 784
 785 /*
 786  * Initialize ResultRelInfo data for one result relation
 787  */
 788 static void
 789 initResultRelInfo(ResultRelInfo *resultRelInfo,
 790                                   Index resultRelationIndex,
 791                                   List *rangeTable,
 792                                   CmdType operation)
 793 {
 794         Oid                     resultRelationOid;
 795         Relation        resultRelationDesc;
 796
 797         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 798         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 799
 800         switch (resultRelationDesc->rd_rel->relkind)
 801         {
 802                 case RELKIND_SEQUENCE:
 803                         elog(ERROR, "You can't change sequence relation %s",
 804                                  RelationGetRelationName(resultRelationDesc));
 805                         break;
 806                 case RELKIND_TOASTVALUE:
 807                         elog(ERROR, "You can't change toast relation %s",
 808                                  RelationGetRelationName(resultRelationDesc));
 809                         break;
 810                 case RELKIND_VIEW:
 811                         elog(ERROR, "You can't change view relation %s",
 812                                  RelationGetRelationName(resultRelationDesc));
 813                         break;
 814         }
 815
 816         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 817         resultRelInfo->type = T_ResultRelInfo;
 818         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 819         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 820         resultRelInfo->ri_NumIndices = 0;
 821         resultRelInfo->ri_IndexRelationDescs = NULL;
 822         resultRelInfo->ri_IndexRelationInfo = NULL;
 823         resultRelInfo->ri_ConstraintExprs = NULL;
 824         resultRelInfo->ri_junkFilter = NULL;
 825
 826         /*
 827          * If there are indices on the result relation, open them and save
 828          * descriptors in the result relation info, so that we can add new
 829          * index entries for the tuples we add/update.  We need not do this
 830          * for a DELETE, however, since deletion doesn't affect indexes.
 831          */
 832         if (resultRelationDesc->rd_rel->relhasindex &&
 833                 operation != CMD_DELETE)
 834                 ExecOpenIndices(resultRelInfo);
 835 }
 836
 837 /* ----------------------------------------------------------------
 838  *              EndPlan
 839  *
 840  *              Cleans up the query plan -- closes files and free up storages
 841  * ----------------------------------------------------------------
 842  */
 843 static void
 844 EndPlan(Plan *plan, EState *estate)
 845 {
 846         ResultRelInfo *resultRelInfo;
 847         int                     i;
 848         List       *l;
 849
 850         /*
 851          * shut down any PlanQual processing we were doing
 852          */
 853         if (estate->es_evalPlanQual != NULL)
 854                 EndEvalPlanQual(estate);
 855
 856         /*
 857          * shut down the node-type-specific query processing
 858          */
 859         ExecEndNode(plan, plan);
 860
 861         /*
 862          * destroy the executor "tuple" table.
 863          */
 864         ExecDropTupleTable(estate->es_tupleTable, true);
 865         estate->es_tupleTable = NULL;
 866
 867         /*
 868          * close the result relation(s) if any, but hold locks until xact
 869          * commit.      Also clean up junkfilters if present.
 870          */
 871         resultRelInfo = estate->es_result_relations;
 872         for (i = estate->es_num_result_relations; i > 0; i--)
 873         {
 874                 /* Close indices and then the relation itself */
 875                 ExecCloseIndices(resultRelInfo);
 876                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 877                 /* Delete the junkfilter if any */
 878                 if (resultRelInfo->ri_junkFilter != NULL)
 879                         ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
 880                 resultRelInfo++;
 881         }
 882
 883         /*
 884          * close the "into" relation if necessary, again keeping lock
 885          */
 886         if (estate->es_into_relation_descriptor != NULL)
 887                 heap_close(estate->es_into_relation_descriptor, NoLock);
 888
 889         /*
 890          * There might be a junkfilter without a result relation.
 891          */
 892         if (estate->es_num_result_relations == 0 &&
 893                 estate->es_junkFilter != NULL)
 894         {
 895                 ExecFreeJunkFilter(estate->es_junkFilter);
 896                 estate->es_junkFilter = NULL;
 897         }
 898
 899         /*
 900          * close any relations selected FOR UPDATE, again keeping locks
 901          */
 902         foreach(l, estate->es_rowMark)
 903         {
 904                 execRowMark *erm = lfirst(l);
 905
 906                 heap_close(erm->relation, NoLock);
 907         }
 908 }
 909
 910 /* ----------------------------------------------------------------
 911  *              ExecutePlan
 912  *
 913  *              processes the query plan to retrieve 'numberTuples' tuples in the
 914  *              direction specified.
 915  *              Retrieves all tuples if tupleCount is 0
 916  *
 917  *              result is either a slot containing the last tuple in the case
 918  *              of a RETRIEVE or NULL otherwise.
 919  *
 920  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 921  * user can see it
 922  * ----------------------------------------------------------------
 923  */
 924 static TupleTableSlot *
 925 ExecutePlan(EState *estate,
 926                         Plan *plan,
 927                         CmdType operation,
 928                         long numberTuples,
 929                         ScanDirection direction,
 930                         DestReceiver *destfunc)
 931 {
 932         JunkFilter *junkfilter;
 933         TupleTableSlot *slot;
 934         ItemPointer tupleid = NULL;
 935         ItemPointerData tuple_ctid;
 936         long            current_tuple_count;
 937         TupleTableSlot *result;
 938
 939         /*
 940          * initialize local variables
 941          */
 942         slot = NULL;
 943         current_tuple_count = 0;
 944         result = NULL;
 945
 946         /*
 947          * Set the direction.
 948          */
 949         estate->es_direction = direction;
 950
 951         /*
 952          * Loop until we've processed the proper number of tuples from the
 953          * plan.
 954          */
 955
 956         for (;;)
 957         {
 958                 /* Reset the per-output-tuple exprcontext */
 959                 ResetPerTupleExprContext(estate);
 960
 961                 /*
 962                  * Execute the plan and obtain a tuple
 963                  */
 964                 /* at the top level, the parent of a plan (2nd arg) is itself */
 965 lnext:  ;
 966                 if (estate->es_useEvalPlan)
 967                 {
 968                         slot = EvalPlanQualNext(estate);
 969                         if (TupIsNull(slot))
 970                                 slot = ExecProcNode(plan, plan);
 971                 }
 972                 else
 973                         slot = ExecProcNode(plan, plan);
 974
 975                 /*
 976                  * if the tuple is null, then we assume there is nothing more to
 977                  * process so we just return null...
 978                  */
 979                 if (TupIsNull(slot))
 980                 {
 981                         result = NULL;
 982                         break;
 983                 }
 984
 985                 /*
 986                  * if we have a junk filter, then project a new tuple with the
 987                  * junk removed.
 988                  *
 989                  * Store this new "clean" tuple in the place of the original tuple.
 990                  *
 991                  * Also, extract all the junk information we need.
 992                  */
 993                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
 994                 {
 995                         Datum           datum;
 996                         HeapTuple       newTuple;
 997                         bool            isNull;
 998
 999                         /*
1000                          * extract the 'ctid' junk attribute.
1001                          */
1002                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1003                         {
1004                                 if (!ExecGetJunkAttribute(junkfilter,
1005                                                                                   slot,
1006                                                                                   "ctid",
1007                                                                                   &datum,
1008                                                                                   &isNull))
1009                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
1010
1011                                 /* shouldn't ever get a null result... */
1012                                 if (isNull)
1013                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
1014
1015                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1016                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1017                                                                                  * ctid!! */
1018                                 tupleid = &tuple_ctid;
1019                         }
1020                         else if (estate->es_rowMark != NIL)
1021                         {
1022                                 List       *l;
1023
1024                 lmark:  ;
1025                                 foreach(l, estate->es_rowMark)
1026                                 {
1027                                         execRowMark *erm = lfirst(l);
1028                                         Buffer          buffer;
1029                                         HeapTupleData tuple;
1030                                         TupleTableSlot *newSlot;
1031                                         int                     test;
1032
1033                                         if (!ExecGetJunkAttribute(junkfilter,
1034                                                                                           slot,
1035                                                                                           erm->resname,
1036                                                                                           &datum,
1037                                                                                           &isNull))
1038                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1039                                                          erm->resname);
1040
1041                                         /*
1042                                          * Unlike the UPDATE/DELETE case, a null result is
1043                                          * possible here, when the referenced table is on the
1044                                          * nullable side of an outer join.      Ignore nulls.
1045                                          */
1046                                         if (isNull)
1047                                                 continue;
1048
1049                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1050                                         test = heap_mark4update(erm->relation, &tuple, &buffer);
1051                                         ReleaseBuffer(buffer);
1052                                         switch (test)
1053                                         {
1054                                                 case HeapTupleSelfUpdated:
1055                                                 case HeapTupleMayBeUpdated:
1056                                                         break;
1057
1058                                                 case HeapTupleUpdated:
1059                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1060                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1061                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1062                                                                   (ItemPointer) DatumGetPointer(datum))))
1063                                                         {
1064                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1065                                                                 if (!(TupIsNull(newSlot)))
1066                                                                 {
1067                                                                         slot = newSlot;
1068                                                                         estate->es_useEvalPlan = true;
1069                                                                         goto lmark;
1070                                                                 }
1071                                                         }
1072
1073                                                         /*
1074                                                          * if tuple was deleted or PlanQual failed for
1075                                                          * updated tuple - we have not return this
1076                                                          * tuple!
1077                                                          */
1078                                                         goto lnext;
1079
1080                                                 default:
1081                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1082                                                         return (NULL);
1083                                         }
1084                                 }
1085                         }
1086
1087                         /*
1088                          * Finally create a new "clean" tuple with all junk attributes
1089                          * removed
1090                          */
1091                         newTuple = ExecRemoveJunk(junkfilter, slot);
1092
1093                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1094                                                                   slot, /* destination slot */
1095                                                                   InvalidBuffer,                /* this tuple has no
1096                                                                                                                  * buffer */
1097                                                                   true);                /* tuple should be pfreed */
1098                 }                                               /* if (junkfilter... */
1099
1100                 /*
1101                  * now that we have a tuple, do the appropriate thing with it..
1102                  * either return it to the user, add it to a relation someplace,
1103                  * delete it from a relation, or modify some of its attributes.
1104                  */
1105
1106                 switch (operation)
1107                 {
1108                         case CMD_SELECT:
1109                                 ExecRetrieve(slot,              /* slot containing tuple */
1110                                                          destfunc,      /* destination's tuple-receiver
1111                                                                                  * obj */
1112                                                          estate);       /* */
1113                                 result = slot;
1114                                 break;
1115
1116                         case CMD_INSERT:
1117                                 ExecAppend(slot, tupleid, estate);
1118                                 result = NULL;
1119                                 break;
1120
1121                         case CMD_DELETE:
1122                                 ExecDelete(slot, tupleid, estate);
1123                                 result = NULL;
1124                                 break;
1125
1126                         case CMD_UPDATE:
1127                                 ExecReplace(slot, tupleid, estate);
1128                                 result = NULL;
1129                                 break;
1130
1131                         default:
1132                                 elog(DEBUG, "ExecutePlan: unknown operation in queryDesc");
1133                                 result = NULL;
1134                                 break;
1135                 }
1136
1137                 /*
1138                  * check our tuple count.. if we've processed the proper number
1139                  * then quit, else loop again and process more tuples..
1140                  */
1141                 current_tuple_count++;
1142                 if (numberTuples == current_tuple_count)
1143                         break;
1144         }
1145
1146         /*
1147          * here, result is either a slot containing a tuple in the case of a
1148          * RETRIEVE or NULL otherwise.
1149          */
1150         return result;
1151 }
1152
1153 /* ----------------------------------------------------------------
1154  *              ExecRetrieve
1155  *
1156  *              RETRIEVEs are easy.. we just pass the tuple to the appropriate
1157  *              print function.  The only complexity is when we do a
1158  *              "retrieve into", in which case we insert the tuple into
1159  *              the appropriate relation (note: this is a newly created relation
1160  *              so we don't need to worry about indices or locks.)
1161  * ----------------------------------------------------------------
1162  */
1163 static void
1164 ExecRetrieve(TupleTableSlot *slot,
1165                          DestReceiver *destfunc,
1166                          EState *estate)
1167 {
1168         HeapTuple       tuple;
1169         TupleDesc       attrtype;
1170
1171         /*
1172          * get the heap tuple out of the tuple table slot
1173          */
1174         tuple = slot->val;
1175         attrtype = slot->ttc_tupleDescriptor;
1176
1177         /*
1178          * insert the tuple into the "into relation"
1179          */
1180         if (estate->es_into_relation_descriptor != NULL)
1181         {
1182                 heap_insert(estate->es_into_relation_descriptor, tuple);
1183                 IncrAppended();
1184         }
1185
1186         /*
1187          * send the tuple to the front end (or the screen)
1188          */
1189         (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1190         IncrRetrieved();
1191         (estate->es_processed)++;
1192 }
1193
1194 /* ----------------------------------------------------------------
1195  *              ExecAppend
1196  *
1197  *              APPENDs are trickier.. we have to insert the tuple into
1198  *              the base relation and insert appropriate tuples into the
1199  *              index relations.
1200  * ----------------------------------------------------------------
1201  */
1202
1203 static void
1204 ExecAppend(TupleTableSlot *slot,
1205                    ItemPointer tupleid,
1206                    EState *estate)
1207 {
1208         HeapTuple       tuple;
1209         ResultRelInfo *resultRelInfo;
1210         Relation        resultRelationDesc;
1211         int                     numIndices;
1212         Oid                     newId;
1213
1214         /*
1215          * get the heap tuple out of the tuple table slot
1216          */
1217         tuple = slot->val;
1218
1219         /*
1220          * get information on the (current) result relation
1221          */
1222         resultRelInfo = estate->es_result_relation_info;
1223         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1224
1225         /* BEFORE ROW INSERT Triggers */
1226         if (resultRelationDesc->trigdesc &&
1227         resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1228         {
1229                 HeapTuple       newtuple;
1230
1231                 newtuple = ExecBRInsertTriggers(estate, resultRelationDesc, tuple);
1232
1233                 if (newtuple == NULL)   /* "do nothing" */
1234                         return;
1235
1236                 if (newtuple != tuple)  /* modified by Trigger(s) */
1237                 {
1238
1239                         /*
1240                          * Insert modified tuple into tuple table slot, replacing the
1241                          * original.  We assume that it was allocated in per-tuple
1242                          * memory context, and therefore will go away by itself. The
1243                          * tuple table slot should not try to clear it.
1244                          */
1245                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1246                         tuple = newtuple;
1247                 }
1248         }
1249
1250         /*
1251          * Check the constraints of the tuple
1252          */
1253         if (resultRelationDesc->rd_att->constr)
1254                 ExecConstraints("ExecAppend", resultRelInfo, slot, estate);
1255
1256         /*
1257          * insert the tuple
1258          */
1259         newId = heap_insert(resultRelationDesc, tuple);
1260
1261         IncrAppended();
1262         (estate->es_processed)++;
1263         estate->es_lastoid = newId;
1264
1265         /*
1266          * process indices
1267          *
1268          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1269          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1270          * field.
1271          */
1272         numIndices = resultRelInfo->ri_NumIndices;
1273         if (numIndices > 0)
1274                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1275
1276         /* AFTER ROW INSERT Triggers */
1277         if (resultRelationDesc->trigdesc)
1278                 ExecARInsertTriggers(estate, resultRelationDesc, tuple);
1279 }
1280
1281 /* ----------------------------------------------------------------
1282  *              ExecDelete
1283  *
1284  *              DELETE is like append, we delete the tuple and its
1285  *              index tuples.
1286  * ----------------------------------------------------------------
1287  */
1288 static void
1289 ExecDelete(TupleTableSlot *slot,
1290                    ItemPointer tupleid,
1291                    EState *estate)
1292 {
1293         ResultRelInfo *resultRelInfo;
1294         Relation        resultRelationDesc;
1295         ItemPointerData ctid;
1296         int                     result;
1297
1298         /*
1299          * get information on the (current) result relation
1300          */
1301         resultRelInfo = estate->es_result_relation_info;
1302         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1303
1304         /* BEFORE ROW DELETE Triggers */
1305         if (resultRelationDesc->trigdesc &&
1306         resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1307         {
1308                 bool            dodelete;
1309
1310                 dodelete = ExecBRDeleteTriggers(estate, tupleid);
1311
1312                 if (!dodelete)                  /* "do nothing" */
1313                         return;
1314         }
1315
1316         /*
1317          * delete the tuple
1318          */
1319 ldelete:;
1320         result = heap_delete(resultRelationDesc, tupleid, &ctid);
1321         switch (result)
1322         {
1323                 case HeapTupleSelfUpdated:
1324                         return;
1325
1326                 case HeapTupleMayBeUpdated:
1327                         break;
1328
1329                 case HeapTupleUpdated:
1330                         if (XactIsoLevel == XACT_SERIALIZABLE)
1331                                 elog(ERROR, "Can't serialize access due to concurrent update");
1332                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1333                         {
1334                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1335                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1336
1337                                 if (!TupIsNull(epqslot))
1338                                 {
1339                                         *tupleid = ctid;
1340                                         goto ldelete;
1341                                 }
1342                         }
1343                         return;
1344
1345                 default:
1346                         elog(ERROR, "Unknown status %u from heap_delete", result);
1347                         return;
1348         }
1349
1350         IncrDeleted();
1351         (estate->es_processed)++;
1352
1353         /*
1354          * Note: Normally one would think that we have to delete index tuples
1355          * associated with the heap tuple now..
1356          *
1357          * ... but in POSTGRES, we have no need to do this because the vacuum
1358          * daemon automatically opens an index scan and deletes index tuples
1359          * when it finds deleted heap tuples. -cim 9/27/89
1360          */
1361
1362         /* AFTER ROW DELETE Triggers */
1363         if (resultRelationDesc->trigdesc)
1364                 ExecARDeleteTriggers(estate, tupleid);
1365 }
1366
1367 /* ----------------------------------------------------------------
1368  *              ExecReplace
1369  *
1370  *              note: we can't run replace queries with transactions
1371  *              off because replaces are actually appends and our
1372  *              scan will mistakenly loop forever, replacing the tuple
1373  *              it just appended..      This should be fixed but until it
1374  *              is, we don't want to get stuck in an infinite loop
1375  *              which corrupts your database..
1376  * ----------------------------------------------------------------
1377  */
1378 static void
1379 ExecReplace(TupleTableSlot *slot,
1380                         ItemPointer tupleid,
1381                         EState *estate)
1382 {
1383         HeapTuple       tuple;
1384         ResultRelInfo *resultRelInfo;
1385         Relation        resultRelationDesc;
1386         ItemPointerData ctid;
1387         int                     result;
1388         int                     numIndices;
1389
1390         /*
1391          * abort the operation if not running transactions
1392          */
1393         if (IsBootstrapProcessingMode())
1394         {
1395                 elog(NOTICE, "ExecReplace: replace can't run without transactions");
1396                 return;
1397         }
1398
1399         /*
1400          * get the heap tuple out of the tuple table slot
1401          */
1402         tuple = slot->val;
1403
1404         /*
1405          * get information on the (current) result relation
1406          */
1407         resultRelInfo = estate->es_result_relation_info;
1408         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1409
1410         /* BEFORE ROW UPDATE Triggers */
1411         if (resultRelationDesc->trigdesc &&
1412         resultRelationDesc->trigdesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1413         {
1414                 HeapTuple       newtuple;
1415
1416                 newtuple = ExecBRUpdateTriggers(estate, tupleid, tuple);
1417
1418                 if (newtuple == NULL)   /* "do nothing" */
1419                         return;
1420
1421                 if (newtuple != tuple)  /* modified by Trigger(s) */
1422                 {
1423
1424                         /*
1425                          * Insert modified tuple into tuple table slot, replacing the
1426                          * original.  We assume that it was allocated in per-tuple
1427                          * memory context, and therefore will go away by itself. The
1428                          * tuple table slot should not try to clear it.
1429                          */
1430                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1431                         tuple = newtuple;
1432                 }
1433         }
1434
1435         /*
1436          * Check the constraints of the tuple
1437          */
1438         if (resultRelationDesc->rd_att->constr)
1439                 ExecConstraints("ExecReplace", resultRelInfo, slot, estate);
1440
1441         /*
1442          * replace the heap tuple
1443          */
1444 lreplace:;
1445         result = heap_update(resultRelationDesc, tupleid, tuple, &ctid);
1446         switch (result)
1447         {
1448                 case HeapTupleSelfUpdated:
1449                         return;
1450
1451                 case HeapTupleMayBeUpdated:
1452                         break;
1453
1454                 case HeapTupleUpdated:
1455                         if (XactIsoLevel == XACT_SERIALIZABLE)
1456                                 elog(ERROR, "Can't serialize access due to concurrent update");
1457                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1458                         {
1459                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1460                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1461
1462                                 if (!TupIsNull(epqslot))
1463                                 {
1464                                         *tupleid = ctid;
1465                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1466                                         slot = ExecStoreTuple(tuple, slot, InvalidBuffer, true);
1467                                         goto lreplace;
1468                                 }
1469                         }
1470                         return;
1471
1472                 default:
1473                         elog(ERROR, "Unknown status %u from heap_update", result);
1474                         return;
1475         }
1476
1477         IncrReplaced();
1478         (estate->es_processed)++;
1479
1480         /*
1481          * Note: instead of having to update the old index tuples associated
1482          * with the heap tuple, all we do is form and insert new index tuples.
1483          * This is because replaces are actually deletes and inserts and index
1484          * tuple deletion is done automagically by the vacuum daemon. All we
1485          * do is insert new index tuples.  -cim 9/27/89
1486          */
1487
1488         /*
1489          * process indices
1490          *
1491          * heap_update updates a tuple in the base relation by invalidating it
1492          * and then appending a new tuple to the relation.      As a side effect,
1493          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1494          * field.  So we now insert index tuples using the new tupleid stored
1495          * there.
1496          */
1497
1498         numIndices = resultRelInfo->ri_NumIndices;
1499         if (numIndices > 0)
1500                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, true);
1501
1502         /* AFTER ROW UPDATE Triggers */
1503         if (resultRelationDesc->trigdesc)
1504                 ExecARUpdateTriggers(estate, tupleid, tuple);
1505 }
1506
1507 static char *
1508 ExecRelCheck(ResultRelInfo *resultRelInfo,
1509                          TupleTableSlot *slot, EState *estate)
1510 {
1511         Relation        rel = resultRelInfo->ri_RelationDesc;
1512         int                     ncheck = rel->rd_att->constr->num_check;
1513         ConstrCheck *check = rel->rd_att->constr->check;
1514         ExprContext *econtext;
1515         MemoryContext oldContext;
1516         List       *qual;
1517         int                     i;
1518
1519         /*
1520          * If first time through for this result relation, build expression
1521          * nodetrees for rel's constraint expressions.  Keep them in the
1522          * per-query memory context so they'll survive throughout the query.
1523          */
1524         if (resultRelInfo->ri_ConstraintExprs == NULL)
1525         {
1526                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1527                 resultRelInfo->ri_ConstraintExprs =
1528                         (List **) palloc(ncheck * sizeof(List *));
1529                 for (i = 0; i < ncheck; i++)
1530                 {
1531                         qual = (List *) stringToNode(check[i].ccbin);
1532                         resultRelInfo->ri_ConstraintExprs[i] = qual;
1533                 }
1534                 MemoryContextSwitchTo(oldContext);
1535         }
1536
1537         /*
1538          * We will use the EState's per-tuple context for evaluating
1539          * constraint expressions (creating it if it's not already there).
1540          */
1541         econtext = GetPerTupleExprContext(estate);
1542
1543         /* Arrange for econtext's scan tuple to be the tuple under test */
1544         econtext->ecxt_scantuple = slot;
1545
1546         /* And evaluate the constraints */
1547         for (i = 0; i < ncheck; i++)
1548         {
1549                 qual = resultRelInfo->ri_ConstraintExprs[i];
1550
1551                 /*
1552                  * NOTE: SQL92 specifies that a NULL result from a constraint
1553                  * expression is not to be treated as a failure.  Therefore, tell
1554                  * ExecQual to return TRUE for NULL.
1555                  */
1556                 if (!ExecQual(qual, econtext, true))
1557                         return check[i].ccname;
1558         }
1559
1560         /* NULL result means no error */
1561         return (char *) NULL;
1562 }
1563
1564 void
1565 ExecConstraints(char *caller, ResultRelInfo *resultRelInfo,
1566                                 TupleTableSlot *slot, EState *estate)
1567 {
1568         Relation        rel = resultRelInfo->ri_RelationDesc;
1569         HeapTuple       tuple = slot->val;
1570         TupleConstr *constr = rel->rd_att->constr;
1571
1572         Assert(constr);
1573
1574         if (constr->has_not_null)
1575         {
1576                 int                     natts = rel->rd_att->natts;
1577                 int                     attrChk;
1578
1579                 for (attrChk = 1; attrChk <= natts; attrChk++)
1580                 {
1581                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1582                                 heap_attisnull(tuple, attrChk))
1583                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1584                                          caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1585                 }
1586         }
1587
1588         if (constr->num_check > 0)
1589         {
1590                 char       *failed;
1591
1592                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1593                         elog(ERROR, "%s: rejected due to CHECK constraint %s",
1594                                  caller, failed);
1595         }
1596 }
1597
1598 TupleTableSlot *
1599 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1600 {
1601         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1602         evalPlanQual *oldepq;
1603         EState     *epqstate = NULL;
1604         Relation        relation;
1605         Buffer          buffer;
1606         HeapTupleData tuple;
1607         bool            endNode = true;
1608
1609         Assert(rti != 0);
1610
1611         if (epq != NULL && epq->rti == 0)
1612         {
1613                 Assert(!(estate->es_useEvalPlan) &&
1614                            epq->estate.es_evalPlanQual == NULL);
1615                 epq->rti = rti;
1616                 endNode = false;
1617         }
1618
1619         /*
1620          * If this is request for another RTE - Ra, - then we have to check
1621          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1622          * updated again and we have to re-start old execution for Ra and
1623          * forget all what we done after Ra was suspended. Cool? -:))
1624          */
1625         if (epq != NULL && epq->rti != rti &&
1626                 epq->estate.es_evTuple[rti - 1] != NULL)
1627         {
1628                 do
1629                 {
1630                         /* pop previous PlanQual from the stack */
1631                         epqstate = &(epq->estate);
1632                         oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1633                         Assert(oldepq->rti != 0);
1634                         /* stop execution */
1635                         ExecEndNode(epq->plan, epq->plan);
1636                         epqstate->es_tupleTable->next = 0;
1637                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1638                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1639                         /* push current PQ to freePQ stack */
1640                         oldepq->free = epq;
1641                         epq = oldepq;
1642                 } while (epq->rti != rti);
1643                 estate->es_evalPlanQual = (Pointer) epq;
1644         }
1645
1646         /*
1647          * If we are requested for another RTE then we have to suspend
1648          * execution of current PlanQual and start execution for new one.
1649          */
1650         if (epq == NULL || epq->rti != rti)
1651         {
1652                 /* try to reuse plan used previously */
1653                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1654
1655                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1656                 {
1657                         newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1658                         /* Init EState */
1659                         epqstate = &(newepq->estate);
1660                         memset(epqstate, 0, sizeof(EState));
1661                         epqstate->type = T_EState;
1662                         epqstate->es_direction = ForwardScanDirection;
1663                         epqstate->es_snapshot = estate->es_snapshot;
1664                         epqstate->es_range_table = estate->es_range_table;
1665                         epqstate->es_param_list_info = estate->es_param_list_info;
1666                         if (estate->es_origPlan->nParamExec > 0)
1667                                 epqstate->es_param_exec_vals = (ParamExecData *)
1668                                         palloc(estate->es_origPlan->nParamExec *
1669                                                    sizeof(ParamExecData));
1670                         epqstate->es_tupleTable =
1671                                 ExecCreateTupleTable(estate->es_tupleTable->size);
1672                         /* ... rest */
1673                         newepq->plan = copyObject(estate->es_origPlan);
1674                         newepq->free = NULL;
1675                         epqstate->es_evTupleNull = (bool *)
1676                                 palloc(length(estate->es_range_table) * sizeof(bool));
1677                         if (epq == NULL)        /* first call */
1678                         {
1679                                 epqstate->es_evTuple = (HeapTuple *)
1680                                         palloc(length(estate->es_range_table) * sizeof(HeapTuple));
1681                                 memset(epqstate->es_evTuple, 0,
1682                                          length(estate->es_range_table) * sizeof(HeapTuple));
1683                         }
1684                         else
1685                                 epqstate->es_evTuple = epq->estate.es_evTuple;
1686                 }
1687                 else
1688                         epqstate = &(newepq->estate);
1689                 /* push current PQ to the stack */
1690                 epqstate->es_evalPlanQual = (Pointer) epq;
1691                 epq = newepq;
1692                 estate->es_evalPlanQual = (Pointer) epq;
1693                 epq->rti = rti;
1694                 endNode = false;
1695         }
1696
1697         epqstate = &(epq->estate);
1698
1699         /*
1700          * Ok - we're requested for the same RTE (-:)). I'm not sure about
1701          * ability to use ExecReScan instead of ExecInitNode, so...
1702          */
1703         if (endNode)
1704         {
1705                 ExecEndNode(epq->plan, epq->plan);
1706                 epqstate->es_tupleTable->next = 0;
1707         }
1708
1709         /* free old RTE' tuple */
1710         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1711         {
1712                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1713                 epqstate->es_evTuple[epq->rti - 1] = NULL;
1714         }
1715
1716         /* ** fetch tid tuple ** */
1717         if (estate->es_result_relation_info != NULL &&
1718                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1719                 relation = estate->es_result_relation_info->ri_RelationDesc;
1720         else
1721         {
1722                 List       *l;
1723
1724                 foreach(l, estate->es_rowMark)
1725                 {
1726                         if (((execRowMark *) lfirst(l))->rti == rti)
1727                                 break;
1728                 }
1729                 relation = ((execRowMark *) lfirst(l))->relation;
1730         }
1731         tuple.t_self = *tid;
1732         for (;;)
1733         {
1734                 heap_fetch(relation, SnapshotDirty, &tuple, &buffer);
1735                 if (tuple.t_data != NULL)
1736                 {
1737                         TransactionId xwait = SnapshotDirty->xmax;
1738
1739                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1740                         {
1741                                 elog(NOTICE, "EvalPlanQual: t_xmin is uncommitted ?!");
1742                                 Assert(!TransactionIdIsValid(SnapshotDirty->xmin));
1743                                 elog(ERROR, "Aborting this transaction");
1744                         }
1745
1746                         /*
1747                          * If tuple is being updated by other transaction then we have
1748                          * to wait for its commit/abort.
1749                          */
1750                         if (TransactionIdIsValid(xwait))
1751                         {
1752                                 ReleaseBuffer(buffer);
1753                                 XactLockTableWait(xwait);
1754                                 continue;
1755                         }
1756
1757                         /*
1758                          * Nice! We got tuple - now copy it.
1759                          */
1760                         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1761                                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1762                         epqstate->es_evTuple[epq->rti - 1] = heap_copytuple(&tuple);
1763                         ReleaseBuffer(buffer);
1764                         break;
1765                 }
1766
1767                 /*
1768                  * Ops! Invalid tuple. Have to check is it updated or deleted.
1769                  * Note that it's possible to get invalid SnapshotDirty->tid if
1770                  * tuple updated by this transaction. Have we to check this ?
1771                  */
1772                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1773                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1774                 {
1775                         tuple.t_self = SnapshotDirty->tid;      /* updated ... */
1776                         continue;
1777                 }
1778
1779                 /*
1780                  * Deleted or updated by this transaction. Do not (re-)start
1781                  * execution of this PQ. Continue previous PQ.
1782                  */
1783                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1784                 if (oldepq != NULL)
1785                 {
1786                         Assert(oldepq->rti != 0);
1787                         /* push current PQ to freePQ stack */
1788                         oldepq->free = epq;
1789                         epq = oldepq;
1790                         epqstate = &(epq->estate);
1791                         estate->es_evalPlanQual = (Pointer) epq;
1792                 }
1793                 else
1794                 {
1795                         epq->rti = 0;           /* this is the first (oldest) */
1796                         estate->es_useEvalPlan = false;         /* PQ - mark as free and          */
1797                         return (NULL);          /* continue Query execution   */
1798                 }
1799         }
1800
1801         if (estate->es_origPlan->nParamExec > 0)
1802                 memset(epqstate->es_param_exec_vals, 0,
1803                            estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1804         memset(epqstate->es_evTupleNull, false,
1805                    length(estate->es_range_table) * sizeof(bool));
1806         Assert(epqstate->es_tupleTable->next == 0);
1807         ExecInitNode(epq->plan, epqstate, NULL);
1808
1809         /*
1810          * For UPDATE/DELETE we have to return tid of actual row we're
1811          * executing PQ for.
1812          */
1813         *tid = tuple.t_self;
1814
1815         return EvalPlanQualNext(estate);
1816 }
1817
1818 static TupleTableSlot *
1819 EvalPlanQualNext(EState *estate)
1820 {
1821         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1822         EState     *epqstate = &(epq->estate);
1823         evalPlanQual *oldepq;
1824         TupleTableSlot *slot;
1825
1826         Assert(epq->rti != 0);
1827
1828 lpqnext:;
1829         slot = ExecProcNode(epq->plan, epq->plan);
1830
1831         /*
1832          * No more tuples for this PQ. Continue previous one.
1833          */
1834         if (TupIsNull(slot))
1835         {
1836                 ExecEndNode(epq->plan, epq->plan);
1837                 epqstate->es_tupleTable->next = 0;
1838                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1839                 epqstate->es_evTuple[epq->rti - 1] = NULL;
1840                 /* pop old PQ from the stack */
1841                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1842                 if (oldepq == (evalPlanQual *) NULL)
1843                 {
1844                         epq->rti = 0;           /* this is the first (oldest) */
1845                         estate->es_useEvalPlan = false;         /* PQ - mark as free and          */
1846                         return (NULL);          /* continue Query execution   */
1847                 }
1848                 Assert(oldepq->rti != 0);
1849                 /* push current PQ to freePQ stack */
1850                 oldepq->free = epq;
1851                 epq = oldepq;
1852                 epqstate = &(epq->estate);
1853                 estate->es_evalPlanQual = (Pointer) epq;
1854                 goto lpqnext;
1855         }
1856
1857         return (slot);
1858 }
1859
1860 static void
1861 EndEvalPlanQual(EState *estate)
1862 {
1863         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1864         EState     *epqstate = &(epq->estate);
1865         evalPlanQual *oldepq;
1866
1867         if (epq->rti == 0)                      /* plans already shutdowned */
1868         {
1869                 Assert(epq->estate.es_evalPlanQual == NULL);
1870                 return;
1871         }
1872
1873         for (;;)
1874         {
1875                 ExecEndNode(epq->plan, epq->plan);
1876                 epqstate->es_tupleTable->next = 0;
1877                 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1878                 {
1879                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1880                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1881                 }
1882                 /* pop old PQ from the stack */
1883                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1884                 if (oldepq == (evalPlanQual *) NULL)
1885                 {
1886                         epq->rti = 0;           /* this is the first (oldest) */
1887                         estate->es_useEvalPlan = false;         /* PQ - mark as free */
1888                         break;
1889                 }
1890                 Assert(oldepq->rti != 0);
1891                 /* push current PQ to freePQ stack */
1892                 oldepq->free = epq;
1893                 epq = oldepq;
1894                 epqstate = &(epq->estate);
1895                 estate->es_evalPlanQual = (Pointer) epq;
1896         }
1897 }