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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 is required as an argument.
  16  *
  17  *      ExecutorStart() must be called at the beginning of execution of any
  18  *      query plan and ExecutorEnd() should always be called at the end of
  19  *      execution of a plan.
  20  *
  21  *      ExecutorRun accepts direction and count arguments that specify whether
  22  *      the plan is to be executed forwards, backwards, and for how many tuples.
  23  *
  24  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  25  * Portions Copyright (c) 1994, Regents of the University of California
  26  *
  27  *
  28  * IDENTIFICATION
  29  *        $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.209 2003/05/08 18:16:36 tgl Exp $
  30  *
  31  *-------------------------------------------------------------------------
  32  */
  33 #include "postgres.h"
  34
  35 #include "access/heapam.h"
  36 #include "catalog/heap.h"
  37 #include "catalog/namespace.h"
  38 #include "commands/tablecmds.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 #include "utils/lsyscache.h"
  47
  48
  49 typedef struct execRowMark
  50 {
  51         Relation        relation;
  52         Index           rti;
  53         char            resname[32];
  54 } execRowMark;
  55
  56 typedef struct evalPlanQual
  57 {
  58         Index           rti;
  59         EState     *estate;
  60         PlanState  *planstate;
  61         struct evalPlanQual *next;      /* stack of active PlanQual plans */
  62         struct evalPlanQual *free;      /* list of free PlanQual plans */
  63 } evalPlanQual;
  64
  65 /* decls for local routines only used within this module */
  66 static void InitPlan(QueryDesc *queryDesc, bool explainOnly);
  67 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  68                                   Index resultRelationIndex,
  69                                   List *rangeTable,
  70                                   CmdType operation);
  71 static TupleTableSlot *ExecutePlan(EState *estate, PlanState *planstate,
  72                         CmdType operation,
  73                         long numberTuples,
  74                         ScanDirection direction,
  75                         DestReceiver *dest);
  76 static void ExecSelect(TupleTableSlot *slot,
  77                    DestReceiver *dest,
  78                    EState *estate);
  79 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
  80                    EState *estate);
  81 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  82                    EState *estate);
  83 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
  84                    EState *estate);
  85 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  86 static void EndEvalPlanQual(EState *estate);
  87 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
  88 static void ExecCheckXactReadOnly(Query *parsetree, CmdType operation);
  89 static void EvalPlanQualStart(evalPlanQual *epq, EState *estate,
  90                                                           evalPlanQual *priorepq);
  91 static void EvalPlanQualStop(evalPlanQual *epq);
  92
  93 /* end of local decls */
  94
  95
  96 /* ----------------------------------------------------------------
  97  *              ExecutorStart
  98  *
  99  *              This routine must be called at the beginning of any execution of any
 100  *              query plan
 101  *
 102  * Takes a QueryDesc previously created by CreateQueryDesc (it's not real
 103  * clear why we bother to separate the two functions, but...).  The tupDesc
 104  * field of the QueryDesc is filled in to describe the tuples that will be
 105  * returned, and the internal fields (estate and planstate) are set up.
 106  *
 107  * If explainOnly is true, we are not actually intending to run the plan,
 108  * only to set up for EXPLAIN; so skip unwanted side-effects.
 109  *
 110  * NB: the CurrentMemoryContext when this is called will become the parent
 111  * of the per-query context used for this Executor invocation.
 112  * ----------------------------------------------------------------
 113  */
 114 void
 115 ExecutorStart(QueryDesc *queryDesc, bool explainOnly)
 116 {
 117         EState     *estate;
 118         MemoryContext oldcontext;
 119
 120         /* sanity checks: queryDesc must not be started already */
 121         Assert(queryDesc != NULL);
 122         Assert(queryDesc->estate == NULL);
 123
 124         /*
 125          * If the transaction is read-only, we need to check if any writes
 126          * are planned to non-temporary tables.
 127          */
 128         if (!explainOnly)
 129                 ExecCheckXactReadOnly(queryDesc->parsetree, queryDesc->operation);
 130
 131         /*
 132          * Build EState, switch into per-query memory context for startup.
 133          */
 134         estate = CreateExecutorState();
 135         queryDesc->estate = estate;
 136
 137         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 138
 139         /*
 140          * Fill in parameters, if any, from queryDesc
 141          */
 142         estate->es_param_list_info = queryDesc->params;
 143
 144         if (queryDesc->plantree->nParamExec > 0)
 145                 estate->es_param_exec_vals = (ParamExecData *)
 146                         palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 147
 148         estate->es_instrument = queryDesc->doInstrument;
 149
 150         /*
 151          * Make our own private copy of the current query snapshot data.
 152          *
 153          * This "freezes" our idea of which tuples are good and which are not for
 154          * the life of this query, even if it outlives the current command and
 155          * current snapshot.
 156          */
 157         estate->es_snapshot = CopyQuerySnapshot();
 158
 159         /*
 160          * Initialize the plan state tree
 161          */
 162         InitPlan(queryDesc, explainOnly);
 163
 164         MemoryContextSwitchTo(oldcontext);
 165 }
 166
 167 /* ----------------------------------------------------------------
 168  *              ExecutorRun
 169  *
 170  *              This is the main routine of the executor module. It accepts
 171  *              the query descriptor from the traffic cop and executes the
 172  *              query plan.
 173  *
 174  *              ExecutorStart must have been called already.
 175  *
 176  *              If direction is NoMovementScanDirection then nothing is done
 177  *              except to start up/shut down the destination.  Otherwise,
 178  *              we retrieve up to 'count' tuples in the specified direction.
 179  *
 180  *              Note: count = 0 is interpreted as no portal limit, i.e., run to
 181  *              completion.
 182  *
 183  * ----------------------------------------------------------------
 184  */
 185 TupleTableSlot *
 186 ExecutorRun(QueryDesc *queryDesc,
 187                         ScanDirection direction, long count)
 188 {
 189         EState     *estate;
 190         CmdType         operation;
 191         DestReceiver *dest;
 192         TupleTableSlot *result;
 193         MemoryContext oldcontext;
 194
 195         /* sanity checks */
 196         Assert(queryDesc != NULL);
 197
 198         estate = queryDesc->estate;
 199
 200         Assert(estate != NULL);
 201
 202         /*
 203          * Switch into per-query memory context
 204          */
 205         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 206
 207         /*
 208          * extract information from the query descriptor and the query
 209          * feature.
 210          */
 211         operation = queryDesc->operation;
 212         dest = queryDesc->dest;
 213
 214         /*
 215          * startup tuple receiver
 216          */
 217         estate->es_processed = 0;
 218         estate->es_lastoid = InvalidOid;
 219
 220         (*dest->startup) (dest, operation, queryDesc->tupDesc);
 221
 222         /*
 223          * run plan
 224          */
 225         if (direction == NoMovementScanDirection)
 226                 result = NULL;
 227         else
 228                 result = ExecutePlan(estate,
 229                                                          queryDesc->planstate,
 230                                                          operation,
 231                                                          count,
 232                                                          direction,
 233                                                          dest);
 234
 235         /*
 236          * shutdown receiver
 237          */
 238         (*dest->shutdown) (dest);
 239
 240         MemoryContextSwitchTo(oldcontext);
 241
 242         return result;
 243 }
 244
 245 /* ----------------------------------------------------------------
 246  *              ExecutorEnd
 247  *
 248  *              This routine must be called at the end of execution of any
 249  *              query plan
 250  * ----------------------------------------------------------------
 251  */
 252 void
 253 ExecutorEnd(QueryDesc *queryDesc)
 254 {
 255         EState     *estate;
 256         MemoryContext oldcontext;
 257
 258         /* sanity checks */
 259         Assert(queryDesc != NULL);
 260
 261         estate = queryDesc->estate;
 262
 263         Assert(estate != NULL);
 264
 265         /*
 266          * Switch into per-query memory context to run ExecEndPlan
 267          */
 268         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 269
 270         ExecEndPlan(queryDesc->planstate, estate);
 271
 272         /*
 273          * Must switch out of context before destroying it
 274          */
 275         MemoryContextSwitchTo(oldcontext);
 276
 277         /*
 278          * Release EState and per-query memory context.  This should release
 279          * everything the executor has allocated.
 280          */
 281         FreeExecutorState(estate);
 282
 283         /* Reset queryDesc fields that no longer point to anything */
 284         queryDesc->tupDesc = NULL;
 285         queryDesc->estate = NULL;
 286         queryDesc->planstate = NULL;
 287 }
 288
 289 /* ----------------------------------------------------------------
 290  *              ExecutorRewind
 291  *
 292  *              This routine may be called on an open queryDesc to rewind it
 293  *              to the start.
 294  * ----------------------------------------------------------------
 295  */
 296 void
 297 ExecutorRewind(QueryDesc *queryDesc)
 298 {
 299         EState     *estate;
 300         MemoryContext oldcontext;
 301
 302         /* sanity checks */
 303         Assert(queryDesc != NULL);
 304
 305         estate = queryDesc->estate;
 306
 307         Assert(estate != NULL);
 308
 309         /* It's probably not sensible to rescan updating queries */
 310         Assert(queryDesc->operation == CMD_SELECT);
 311
 312         /*
 313          * Switch into per-query memory context
 314          */
 315         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 316
 317         /*
 318          * rescan plan
 319          */
 320         ExecReScan(queryDesc->planstate, NULL);
 321
 322         MemoryContextSwitchTo(oldcontext);
 323 }
 324
 325
 326 /*
 327  * ExecCheckRTPerms
 328  *              Check access permissions for all relations listed in a range table.
 329  */
 330 void
 331 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 332 {
 333         List       *lp;
 334
 335         foreach(lp, rangeTable)
 336         {
 337                 RangeTblEntry *rte = lfirst(lp);
 338
 339                 ExecCheckRTEPerms(rte, operation);
 340         }
 341 }
 342
 343 /*
 344  * ExecCheckRTEPerms
 345  *              Check access permissions for a single RTE.
 346  */
 347 static void
 348 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 349 {
 350         Oid                     relOid;
 351         AclId           userid;
 352         AclResult       aclcheck_result;
 353
 354         /*
 355          * If it's a subquery, recursively examine its rangetable.
 356          */
 357         if (rte->rtekind == RTE_SUBQUERY)
 358         {
 359                 ExecCheckRTPerms(rte->subquery->rtable, operation);
 360                 return;
 361         }
 362
 363         /*
 364          * Otherwise, only plain-relation RTEs need to be checked here.
 365          * Function RTEs are checked by init_fcache when the function is prepared
 366          * for execution. Join and special RTEs need no checks.
 367          */
 368         if (rte->rtekind != RTE_RELATION)
 369                 return;
 370
 371         relOid = rte->relid;
 372
 373         /*
 374          * userid to check as: current user unless we have a setuid
 375          * indication.
 376          *
 377          * Note: GetUserId() is presently fast enough that there's no harm in
 378          * calling it separately for each RTE.  If that stops being true, we
 379          * could call it once in ExecCheckRTPerms and pass the userid down
 380          * from there.  But for now, no need for the extra clutter.
 381          */
 382         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 383
 384 #define CHECK(MODE)             pg_class_aclcheck(relOid, userid, MODE)
 385
 386         if (rte->checkForRead)
 387         {
 388                 aclcheck_result = CHECK(ACL_SELECT);
 389                 if (aclcheck_result != ACLCHECK_OK)
 390                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 391         }
 392
 393         if (rte->checkForWrite)
 394         {
 395                 /*
 396                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 397                  * Right now we don't distinguish that from true update as far as
 398                  * permissions checks are concerned.
 399                  */
 400                 switch (operation)
 401                 {
 402                         case CMD_INSERT:
 403                                 aclcheck_result = CHECK(ACL_INSERT);
 404                                 break;
 405                         case CMD_SELECT:
 406                         case CMD_UPDATE:
 407                                 aclcheck_result = CHECK(ACL_UPDATE);
 408                                 break;
 409                         case CMD_DELETE:
 410                                 aclcheck_result = CHECK(ACL_DELETE);
 411                                 break;
 412                         default:
 413                                 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
 414                                          operation);
 415                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 416                                 break;
 417                 }
 418                 if (aclcheck_result != ACLCHECK_OK)
 419                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 420         }
 421 }
 422
 423 static void
 424 ExecCheckXactReadOnly(Query *parsetree, CmdType operation)
 425 {
 426         if (!XactReadOnly)
 427                 return;
 428
 429         /* CREATE TABLE AS or SELECT INTO */
 430         if (operation == CMD_SELECT && parsetree->into != NULL)
 431                 goto fail;
 432
 433         if (operation == CMD_DELETE || operation == CMD_INSERT
 434                 || operation == CMD_UPDATE)
 435         {
 436                 List *lp;
 437
 438                 foreach(lp, parsetree->rtable)
 439                 {
 440                         RangeTblEntry *rte = lfirst(lp);
 441
 442                         if (rte->rtekind != RTE_RELATION)
 443                                 continue;
 444
 445                         if (!rte->checkForWrite)
 446                                 continue;
 447
 448                         if (isTempNamespace(get_rel_namespace(rte->relid)))
 449                                 continue;
 450
 451                         goto fail;
 452                 }
 453         }
 454
 455         return;
 456
 457 fail:
 458         elog(ERROR, "transaction is read-only");
 459 }
 460
 461
 462 /* ----------------------------------------------------------------
 463  *              InitPlan
 464  *
 465  *              Initializes the query plan: open files, allocate storage
 466  *              and start up the rule manager
 467  * ----------------------------------------------------------------
 468  */
 469 static void
 470 InitPlan(QueryDesc *queryDesc, bool explainOnly)
 471 {
 472         CmdType         operation = queryDesc->operation;
 473         Query *parseTree = queryDesc->parsetree;
 474         Plan *plan = queryDesc->plantree;
 475         EState *estate = queryDesc->estate;
 476         PlanState  *planstate;
 477         List       *rangeTable;
 478         Relation        intoRelationDesc;
 479         bool            do_select_into;
 480         TupleDesc       tupType;
 481
 482         /*
 483          * Do permissions checks.  It's sufficient to examine the query's
 484          * top rangetable here --- subplan RTEs will be checked during
 485          * ExecInitSubPlan().
 486          */
 487         ExecCheckRTPerms(parseTree->rtable, operation);
 488
 489         /*
 490          * get information from query descriptor
 491          */
 492         rangeTable = parseTree->rtable;
 493
 494         /*
 495          * initialize the node's execution state
 496          */
 497         estate->es_range_table = rangeTable;
 498
 499         /*
 500          * if there is a result relation, initialize result relation stuff
 501          */
 502         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 503         {
 504                 List       *resultRelations = parseTree->resultRelations;
 505                 int                     numResultRelations;
 506                 ResultRelInfo *resultRelInfos;
 507
 508                 if (resultRelations != NIL)
 509                 {
 510                         /*
 511                          * Multiple result relations (due to inheritance)
 512                          * parseTree->resultRelations identifies them all
 513                          */
 514                         ResultRelInfo *resultRelInfo;
 515
 516                         numResultRelations = length(resultRelations);
 517                         resultRelInfos = (ResultRelInfo *)
 518                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 519                         resultRelInfo = resultRelInfos;
 520                         while (resultRelations != NIL)
 521                         {
 522                                 initResultRelInfo(resultRelInfo,
 523                                                                   lfirsti(resultRelations),
 524                                                                   rangeTable,
 525                                                                   operation);
 526                                 resultRelInfo++;
 527                                 resultRelations = lnext(resultRelations);
 528                         }
 529                 }
 530                 else
 531                 {
 532                         /*
 533                          * Single result relation identified by
 534                          * parseTree->resultRelation
 535                          */
 536                         numResultRelations = 1;
 537                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 538                         initResultRelInfo(resultRelInfos,
 539                                                           parseTree->resultRelation,
 540                                                           rangeTable,
 541                                                           operation);
 542                 }
 543
 544                 estate->es_result_relations = resultRelInfos;
 545                 estate->es_num_result_relations = numResultRelations;
 546                 /* Initialize to first or only result rel */
 547                 estate->es_result_relation_info = resultRelInfos;
 548         }
 549         else
 550         {
 551                 /*
 552                  * if no result relation, then set state appropriately
 553                  */
 554                 estate->es_result_relations = NULL;
 555                 estate->es_num_result_relations = 0;
 556                 estate->es_result_relation_info = NULL;
 557         }
 558
 559         /*
 560          * Detect whether we're doing SELECT INTO.  If so, set the force_oids
 561          * flag appropriately so that the plan tree will be initialized with
 562          * the correct tuple descriptors.
 563          */
 564         do_select_into = false;
 565
 566         if (operation == CMD_SELECT && parseTree->into != NULL)
 567         {
 568                 do_select_into = true;
 569                 /*
 570                  * For now, always create OIDs in SELECT INTO; this is for backwards
 571                  * compatibility with pre-7.3 behavior.  Eventually we might want
 572                  * to allow the user to choose.
 573                  */
 574                 estate->es_force_oids = true;
 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                         snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
 597                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 598                 }
 599         }
 600
 601         /*
 602          * initialize the executor "tuple" table.  We need slots for all the
 603          * plan nodes, plus possibly output slots for the junkfilter(s). At
 604          * this point we aren't sure if we need junkfilters, so just add slots
 605          * for them unconditionally.
 606          */
 607         {
 608                 int                     nSlots = ExecCountSlotsNode(plan);
 609
 610                 if (parseTree->resultRelations != NIL)
 611                         nSlots += length(parseTree->resultRelations);
 612                 else
 613                         nSlots += 1;
 614                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 615         }
 616
 617         /* mark EvalPlanQual not active */
 618         estate->es_topPlan = plan;
 619         estate->es_evalPlanQual = NULL;
 620         estate->es_evTupleNull = NULL;
 621         estate->es_evTuple = NULL;
 622         estate->es_useEvalPlan = false;
 623
 624         /*
 625          * initialize the private state information for all the nodes in the
 626          * query tree.  This opens files, allocates storage and leaves us
 627          * ready to start processing tuples.
 628          */
 629         planstate = ExecInitNode(plan, estate);
 630
 631         /*
 632          * Get the tuple descriptor describing the type of tuples to return.
 633          * (this is especially important if we are creating a relation with
 634          * "SELECT INTO")
 635          */
 636         tupType = ExecGetResultType(planstate);
 637
 638         /*
 639          * Initialize the junk filter if needed.  SELECT and INSERT queries need a
 640          * filter if there are any junk attrs in the tlist.  INSERT and SELECT
 641          * INTO also need a filter if the top plan node is a scan node that's not
 642          * doing projection (else we'll be scribbling on the scan tuple!)  UPDATE
 643          * and DELETE always need a filter, since there's always a junk 'ctid'
 644          * attribute present --- no need to look first.
 645          */
 646         {
 647                 bool            junk_filter_needed = false;
 648                 List       *tlist;
 649
 650                 switch (operation)
 651                 {
 652                         case CMD_SELECT:
 653                         case CMD_INSERT:
 654                                 foreach(tlist, plan->targetlist)
 655                                 {
 656                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 657
 658                                         if (tle->resdom->resjunk)
 659                                         {
 660                                                 junk_filter_needed = true;
 661                                                 break;
 662                                         }
 663                                 }
 664                                 if (!junk_filter_needed &&
 665                                         (operation == CMD_INSERT || do_select_into))
 666                                 {
 667                                         if (IsA(planstate, SeqScanState) ||
 668                                                 IsA(planstate, IndexScanState) ||
 669                                                 IsA(planstate, TidScanState) ||
 670                                                 IsA(planstate, SubqueryScanState) ||
 671                                                 IsA(planstate, FunctionScanState))
 672                                         {
 673                                                 if (planstate->ps_ProjInfo == NULL)
 674                                                         junk_filter_needed = true;
 675                                         }
 676                                 }
 677                                 break;
 678                         case CMD_UPDATE:
 679                         case CMD_DELETE:
 680                                 junk_filter_needed = true;
 681                                 break;
 682                         default:
 683                                 break;
 684                 }
 685
 686                 if (junk_filter_needed)
 687                 {
 688                         /*
 689                          * If there are multiple result relations, each one needs its
 690                          * own junk filter.  Note this is only possible for
 691                          * UPDATE/DELETE, so we can't be fooled by some needing a
 692                          * filter and some not.
 693                          */
 694                         if (parseTree->resultRelations != NIL)
 695                         {
 696                                 PlanState **appendplans;
 697                                 int                     as_nplans;
 698                                 ResultRelInfo *resultRelInfo;
 699                                 int                     i;
 700
 701                                 /* Top plan had better be an Append here. */
 702                                 Assert(IsA(plan, Append));
 703                                 Assert(((Append *) plan)->isTarget);
 704                                 Assert(IsA(planstate, AppendState));
 705                                 appendplans = ((AppendState *) planstate)->appendplans;
 706                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 707                                 Assert(as_nplans == estate->es_num_result_relations);
 708                                 resultRelInfo = estate->es_result_relations;
 709                                 for (i = 0; i < as_nplans; i++)
 710                                 {
 711                                         PlanState  *subplan = appendplans[i];
 712                                         JunkFilter *j;
 713
 714                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 715                                                                                    ExecGetResultType(subplan),
 716                                                           ExecAllocTableSlot(estate->es_tupleTable));
 717                                         resultRelInfo->ri_junkFilter = j;
 718                                         resultRelInfo++;
 719                                 }
 720
 721                                 /*
 722                                  * Set active junkfilter too; at this point ExecInitAppend
 723                                  * has already selected an active result relation...
 724                                  */
 725                                 estate->es_junkFilter =
 726                                         estate->es_result_relation_info->ri_junkFilter;
 727                         }
 728                         else
 729                         {
 730                                 /* Normal case with just one JunkFilter */
 731                                 JunkFilter *j;
 732
 733                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 734                                                                            tupType,
 735                                                           ExecAllocTableSlot(estate->es_tupleTable));
 736                                 estate->es_junkFilter = j;
 737                                 if (estate->es_result_relation_info)
 738                                         estate->es_result_relation_info->ri_junkFilter = j;
 739
 740                                 /* For SELECT, want to return the cleaned tuple type */
 741                                 if (operation == CMD_SELECT)
 742                                         tupType = j->jf_cleanTupType;
 743                         }
 744                 }
 745                 else
 746                         estate->es_junkFilter = NULL;
 747         }
 748
 749         /*
 750          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 751          * till now so we have the "clean" result tuple type to create the
 752          * new table from.
 753          *
 754          * If EXPLAIN, skip creating the "into" relation.
 755          */
 756         intoRelationDesc = (Relation) NULL;
 757
 758         if (do_select_into && !explainOnly)
 759         {
 760                 char       *intoName;
 761                 Oid                     namespaceId;
 762                 AclResult       aclresult;
 763                 Oid                     intoRelationId;
 764                 TupleDesc       tupdesc;
 765
 766                 /*
 767                  * find namespace to create in, check permissions
 768                  */
 769                 intoName = parseTree->into->relname;
 770                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 771
 772                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 773                                                                                   ACL_CREATE);
 774                 if (aclresult != ACLCHECK_OK)
 775                         aclcheck_error(aclresult, get_namespace_name(namespaceId));
 776
 777                 /*
 778                  * have to copy tupType to get rid of constraints
 779                  */
 780                 tupdesc = CreateTupleDescCopy(tupType);
 781
 782                 intoRelationId = heap_create_with_catalog(intoName,
 783                                                                                                   namespaceId,
 784                                                                                                   tupdesc,
 785                                                                                                   RELKIND_RELATION,
 786                                                                                                   false,
 787                                                                                                   ONCOMMIT_NOOP,
 788                                                                                                   allowSystemTableMods);
 789
 790                 FreeTupleDesc(tupdesc);
 791
 792                 /*
 793                  * Advance command counter so that the newly-created
 794                  * relation's catalog tuples will be visible to heap_open.
 795                  */
 796                 CommandCounterIncrement();
 797
 798                 /*
 799                  * If necessary, create a TOAST table for the into
 800                  * relation. Note that AlterTableCreateToastTable ends
 801                  * with CommandCounterIncrement(), so that the TOAST table
 802                  * will be visible for insertion.
 803                  */
 804                 AlterTableCreateToastTable(intoRelationId, true);
 805
 806                 /*
 807                  * And open the constructed table for writing.
 808                  */
 809                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 810         }
 811
 812         estate->es_into_relation_descriptor = intoRelationDesc;
 813
 814         queryDesc->tupDesc = tupType;
 815         queryDesc->planstate = planstate;
 816 }
 817
 818 /*
 819  * Initialize ResultRelInfo data for one result relation
 820  */
 821 static void
 822 initResultRelInfo(ResultRelInfo *resultRelInfo,
 823                                   Index resultRelationIndex,
 824                                   List *rangeTable,
 825                                   CmdType operation)
 826 {
 827         Oid                     resultRelationOid;
 828         Relation        resultRelationDesc;
 829
 830         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 831         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 832
 833         switch (resultRelationDesc->rd_rel->relkind)
 834         {
 835                 case RELKIND_SEQUENCE:
 836                         elog(ERROR, "You can't change sequence relation %s",
 837                                  RelationGetRelationName(resultRelationDesc));
 838                         break;
 839                 case RELKIND_TOASTVALUE:
 840                         elog(ERROR, "You can't change toast relation %s",
 841                                  RelationGetRelationName(resultRelationDesc));
 842                         break;
 843                 case RELKIND_VIEW:
 844                         elog(ERROR, "You can't change view relation %s",
 845                                  RelationGetRelationName(resultRelationDesc));
 846                         break;
 847         }
 848
 849         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 850         resultRelInfo->type = T_ResultRelInfo;
 851         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 852         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 853         resultRelInfo->ri_NumIndices = 0;
 854         resultRelInfo->ri_IndexRelationDescs = NULL;
 855         resultRelInfo->ri_IndexRelationInfo = NULL;
 856         /* make a copy so as not to depend on relcache info not changing... */
 857         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 858         resultRelInfo->ri_TrigFunctions = NULL;
 859         resultRelInfo->ri_ConstraintExprs = NULL;
 860         resultRelInfo->ri_junkFilter = NULL;
 861
 862         /*
 863          * If there are indices on the result relation, open them and save
 864          * descriptors in the result relation info, so that we can add new
 865          * index entries for the tuples we add/update.  We need not do this
 866          * for a DELETE, however, since deletion doesn't affect indexes.
 867          */
 868         if (resultRelationDesc->rd_rel->relhasindex &&
 869                 operation != CMD_DELETE)
 870                 ExecOpenIndices(resultRelInfo);
 871 }
 872
 873 /* ----------------------------------------------------------------
 874  *              ExecEndPlan
 875  *
 876  *              Cleans up the query plan -- closes files and frees up storage
 877  *
 878  * NOTE: we are no longer very worried about freeing storage per se
 879  * in this code; FreeExecutorState should be guaranteed to release all
 880  * memory that needs to be released.  What we are worried about doing
 881  * is closing relations and dropping buffer pins.  Thus, for example,
 882  * tuple tables must be cleared or dropped to ensure pins are released.
 883  * ----------------------------------------------------------------
 884  */
 885 void
 886 ExecEndPlan(PlanState *planstate, EState *estate)
 887 {
 888         ResultRelInfo *resultRelInfo;
 889         int                     i;
 890         List       *l;
 891
 892         /*
 893          * shut down any PlanQual processing we were doing
 894          */
 895         if (estate->es_evalPlanQual != NULL)
 896                 EndEvalPlanQual(estate);
 897
 898         /*
 899          * shut down the node-type-specific query processing
 900          */
 901         ExecEndNode(planstate);
 902
 903         /*
 904          * destroy the executor "tuple" table.
 905          */
 906         ExecDropTupleTable(estate->es_tupleTable, true);
 907         estate->es_tupleTable = NULL;
 908
 909         /*
 910          * close the result relation(s) if any, but hold locks until xact
 911          * commit.
 912          */
 913         resultRelInfo = estate->es_result_relations;
 914         for (i = estate->es_num_result_relations; i > 0; i--)
 915         {
 916                 /* Close indices and then the relation itself */
 917                 ExecCloseIndices(resultRelInfo);
 918                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 919                 resultRelInfo++;
 920         }
 921
 922         /*
 923          * close the "into" relation if necessary, again keeping lock
 924          */
 925         if (estate->es_into_relation_descriptor != NULL)
 926                 heap_close(estate->es_into_relation_descriptor, NoLock);
 927
 928         /*
 929          * close any relations selected FOR UPDATE, again keeping locks
 930          */
 931         foreach(l, estate->es_rowMark)
 932         {
 933                 execRowMark *erm = lfirst(l);
 934
 935                 heap_close(erm->relation, NoLock);
 936         }
 937 }
 938
 939 /* ----------------------------------------------------------------
 940  *              ExecutePlan
 941  *
 942  *              processes the query plan to retrieve 'numberTuples' tuples in the
 943  *              direction specified.
 944  *
 945  *              Retrieves all tuples if numberTuples is 0
 946  *
 947  *              result is either a slot containing the last tuple in the case
 948  *              of a SELECT or NULL otherwise.
 949  *
 950  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 951  * user can see it
 952  * ----------------------------------------------------------------
 953  */
 954 static TupleTableSlot *
 955 ExecutePlan(EState *estate,
 956                         PlanState *planstate,
 957                         CmdType operation,
 958                         long numberTuples,
 959                         ScanDirection direction,
 960                         DestReceiver *dest)
 961 {
 962         JunkFilter                      *junkfilter;
 963         TupleTableSlot          *slot;
 964         ItemPointer                      tupleid = NULL;
 965         ItemPointerData          tuple_ctid;
 966         long                             current_tuple_count;
 967         TupleTableSlot          *result;
 968
 969         /*
 970          * initialize local variables
 971          */
 972         slot = NULL;
 973         current_tuple_count = 0;
 974         result = NULL;
 975
 976         /*
 977          * Set the direction.
 978          */
 979         estate->es_direction = direction;
 980
 981         /*
 982          * Process BEFORE EACH STATEMENT triggers
 983          */
 984         switch (operation)
 985         {
 986                 case CMD_UPDATE:
 987                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
 988                         break;
 989                 case CMD_DELETE:
 990                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
 991                         break;
 992                 case CMD_INSERT:
 993                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
 994                         break;
 995                 default:
 996                         /* do nothing */
 997                         break;
 998         }
 999
1000         /*
1001          * Loop until we've processed the proper number of tuples from the
1002          * plan.
1003          */
1004
1005         for (;;)
1006         {
1007                 /* Reset the per-output-tuple exprcontext */
1008                 ResetPerTupleExprContext(estate);
1009
1010                 /*
1011                  * Execute the plan and obtain a tuple
1012                  */
1013 lnext:  ;
1014                 if (estate->es_useEvalPlan)
1015                 {
1016                         slot = EvalPlanQualNext(estate);
1017                         if (TupIsNull(slot))
1018                                 slot = ExecProcNode(planstate);
1019                 }
1020                 else
1021                         slot = ExecProcNode(planstate);
1022
1023                 /*
1024                  * if the tuple is null, then we assume there is nothing more to
1025                  * process so we just return null...
1026                  */
1027                 if (TupIsNull(slot))
1028                 {
1029                         result = NULL;
1030                         break;
1031                 }
1032
1033                 /*
1034                  * if we have a junk filter, then project a new tuple with the
1035                  * junk removed.
1036                  *
1037                  * Store this new "clean" tuple in the junkfilter's resultSlot.
1038                  * (Formerly, we stored it back over the "dirty" tuple, which is
1039                  * WRONG because that tuple slot has the wrong descriptor.)
1040                  *
1041                  * Also, extract all the junk information we need.
1042                  */
1043                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
1044                 {
1045                         Datum           datum;
1046                         HeapTuple       newTuple;
1047                         bool            isNull;
1048
1049                         /*
1050                          * extract the 'ctid' junk attribute.
1051                          */
1052                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1053                         {
1054                                 if (!ExecGetJunkAttribute(junkfilter,
1055                                                                                   slot,
1056                                                                                   "ctid",
1057                                                                                   &datum,
1058                                                                                   &isNull))
1059                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
1060
1061                                 /* shouldn't ever get a null result... */
1062                                 if (isNull)
1063                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
1064
1065                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1066                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1067                                                                                  * ctid!! */
1068                                 tupleid = &tuple_ctid;
1069                         }
1070                         else if (estate->es_rowMark != NIL)
1071                         {
1072                                 List       *l;
1073
1074                 lmark:  ;
1075                                 foreach(l, estate->es_rowMark)
1076                                 {
1077                                         execRowMark *erm = lfirst(l);
1078                                         Buffer          buffer;
1079                                         HeapTupleData tuple;
1080                                         TupleTableSlot *newSlot;
1081                                         int                     test;
1082
1083                                         if (!ExecGetJunkAttribute(junkfilter,
1084                                                                                           slot,
1085                                                                                           erm->resname,
1086                                                                                           &datum,
1087                                                                                           &isNull))
1088                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1089                                                          erm->resname);
1090
1091                                         /* shouldn't ever get a null result... */
1092                                         if (isNull)
1093                                                 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1094                                                          erm->resname);
1095
1096                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1097                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1098                                                                                         estate->es_snapshot->curcid);
1099                                         ReleaseBuffer(buffer);
1100                                         switch (test)
1101                                         {
1102                                                 case HeapTupleSelfUpdated:
1103                                                         /* treat it as deleted; do not process */
1104                                                         goto lnext;
1105
1106                                                 case HeapTupleMayBeUpdated:
1107                                                         break;
1108
1109                                                 case HeapTupleUpdated:
1110                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1111                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1112                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1113                                                                   (ItemPointer) DatumGetPointer(datum))))
1114                                                         {
1115                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1116                                                                 if (!(TupIsNull(newSlot)))
1117                                                                 {
1118                                                                         slot = newSlot;
1119                                                                         estate->es_useEvalPlan = true;
1120                                                                         goto lmark;
1121                                                                 }
1122                                                         }
1123
1124                                                         /*
1125                                                          * if tuple was deleted or PlanQual failed for
1126                                                          * updated tuple - we must not return this
1127                                                          * tuple!
1128                                                          */
1129                                                         goto lnext;
1130
1131                                                 default:
1132                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1133                                                         return (NULL);
1134                                         }
1135                                 }
1136                         }
1137
1138                         /*
1139                          * Finally create a new "clean" tuple with all junk attributes
1140                          * removed
1141                          */
1142                         newTuple = ExecRemoveJunk(junkfilter, slot);
1143
1144                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1145                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1146                                                                   InvalidBuffer,                /* this tuple has no
1147                                                                                                                  * buffer */
1148                                                                   true);                /* tuple should be pfreed */
1149                 }
1150
1151                 /*
1152                  * now that we have a tuple, do the appropriate thing with it..
1153                  * either return it to the user, add it to a relation someplace,
1154                  * delete it from a relation, or modify some of its attributes.
1155                  */
1156                 switch (operation)
1157                 {
1158                         case CMD_SELECT:
1159                                 ExecSelect(slot,        /* slot containing tuple */
1160                                                    dest,        /* destination's tuple-receiver obj */
1161                                                    estate);
1162                                 result = slot;
1163                                 break;
1164
1165                         case CMD_INSERT:
1166                                 ExecInsert(slot, tupleid, estate);
1167                                 result = NULL;
1168                                 break;
1169
1170                         case CMD_DELETE:
1171                                 ExecDelete(slot, tupleid, estate);
1172                                 result = NULL;
1173                                 break;
1174
1175                         case CMD_UPDATE:
1176                                 ExecUpdate(slot, tupleid, estate);
1177                                 result = NULL;
1178                                 break;
1179
1180                         default:
1181                                 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1182                                 result = NULL;
1183                                 break;
1184                 }
1185
1186                 /*
1187                  * check our tuple count.. if we've processed the proper number
1188                  * then quit, else loop again and process more tuples.  Zero
1189                  * numberTuples means no limit.
1190                  */
1191                 current_tuple_count++;
1192                 if (numberTuples && numberTuples == current_tuple_count)
1193                         break;
1194         }
1195
1196         /*
1197          * Process AFTER EACH STATEMENT triggers
1198          */
1199         switch (operation)
1200         {
1201                 case CMD_UPDATE:
1202                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1203                         break;
1204                 case CMD_DELETE:
1205                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1206                         break;
1207                 case CMD_INSERT:
1208                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1209                         break;
1210                 default:
1211                         /* do nothing */
1212                         break;
1213         }
1214
1215         /*
1216          * here, result is either a slot containing a tuple in the case of a
1217          * SELECT or NULL otherwise.
1218          */
1219         return result;
1220 }
1221
1222 /* ----------------------------------------------------------------
1223  *              ExecSelect
1224  *
1225  *              SELECTs are easy.. we just pass the tuple to the appropriate
1226  *              print function.  The only complexity is when we do a
1227  *              "SELECT INTO", in which case we insert the tuple into
1228  *              the appropriate relation (note: this is a newly created relation
1229  *              so we don't need to worry about indices or locks.)
1230  * ----------------------------------------------------------------
1231  */
1232 static void
1233 ExecSelect(TupleTableSlot *slot,
1234                    DestReceiver *dest,
1235                    EState *estate)
1236 {
1237         HeapTuple       tuple;
1238         TupleDesc       attrtype;
1239
1240         /*
1241          * get the heap tuple out of the tuple table slot
1242          */
1243         tuple = slot->val;
1244         attrtype = slot->ttc_tupleDescriptor;
1245
1246         /*
1247          * insert the tuple into the "into relation"
1248          *
1249          * XXX this probably ought to be replaced by a separate destination
1250          */
1251         if (estate->es_into_relation_descriptor != NULL)
1252         {
1253                 heap_insert(estate->es_into_relation_descriptor, tuple,
1254                                         estate->es_snapshot->curcid);
1255                 IncrAppended();
1256         }
1257
1258         /*
1259          * send the tuple to the destination
1260          */
1261         (*dest->receiveTuple) (tuple, attrtype, dest);
1262         IncrRetrieved();
1263         (estate->es_processed)++;
1264 }
1265
1266 /* ----------------------------------------------------------------
1267  *              ExecInsert
1268  *
1269  *              INSERTs are trickier.. we have to insert the tuple into
1270  *              the base relation and insert appropriate tuples into the
1271  *              index relations.
1272  * ----------------------------------------------------------------
1273  */
1274 static void
1275 ExecInsert(TupleTableSlot *slot,
1276                    ItemPointer tupleid,
1277                    EState *estate)
1278 {
1279         HeapTuple       tuple;
1280         ResultRelInfo *resultRelInfo;
1281         Relation        resultRelationDesc;
1282         int                     numIndices;
1283         Oid                     newId;
1284
1285         /*
1286          * get the heap tuple out of the tuple table slot
1287          */
1288         tuple = slot->val;
1289
1290         /*
1291          * get information on the (current) result relation
1292          */
1293         resultRelInfo = estate->es_result_relation_info;
1294         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1295
1296         /* BEFORE ROW INSERT Triggers */
1297         if (resultRelInfo->ri_TrigDesc &&
1298                 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1299         {
1300                 HeapTuple       newtuple;
1301
1302                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1303
1304                 if (newtuple == NULL)   /* "do nothing" */
1305                         return;
1306
1307                 if (newtuple != tuple)  /* modified by Trigger(s) */
1308                 {
1309                         /*
1310                          * Insert modified tuple into tuple table slot, replacing the
1311                          * original.  We assume that it was allocated in per-tuple
1312                          * memory context, and therefore will go away by itself. The
1313                          * tuple table slot should not try to clear it.
1314                          */
1315                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1316                         tuple = newtuple;
1317                 }
1318         }
1319
1320         /*
1321          * Check the constraints of the tuple
1322          */
1323         if (resultRelationDesc->rd_att->constr)
1324                 ExecConstraints("ExecInsert", resultRelInfo, slot, estate);
1325
1326         /*
1327          * insert the tuple
1328          */
1329         newId = heap_insert(resultRelationDesc, tuple,
1330                                                 estate->es_snapshot->curcid);
1331
1332         IncrAppended();
1333         (estate->es_processed)++;
1334         estate->es_lastoid = newId;
1335         setLastTid(&(tuple->t_self));
1336
1337         /*
1338          * process indices
1339          *
1340          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1341          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1342          * field.
1343          */
1344         numIndices = resultRelInfo->ri_NumIndices;
1345         if (numIndices > 0)
1346                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1347
1348         /* AFTER ROW INSERT Triggers */
1349         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1350 }
1351
1352 /* ----------------------------------------------------------------
1353  *              ExecDelete
1354  *
1355  *              DELETE is like UPDATE, we delete the tuple and its
1356  *              index tuples.
1357  * ----------------------------------------------------------------
1358  */
1359 static void
1360 ExecDelete(TupleTableSlot *slot,
1361                    ItemPointer tupleid,
1362                    EState *estate)
1363 {
1364         ResultRelInfo *resultRelInfo;
1365         Relation        resultRelationDesc;
1366         ItemPointerData ctid;
1367         int                     result;
1368
1369         /*
1370          * get information on the (current) result relation
1371          */
1372         resultRelInfo = estate->es_result_relation_info;
1373         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1374
1375         /* BEFORE ROW DELETE Triggers */
1376         if (resultRelInfo->ri_TrigDesc &&
1377           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1378         {
1379                 bool            dodelete;
1380
1381                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1382                                                                                 estate->es_snapshot->curcid);
1383
1384                 if (!dodelete)                  /* "do nothing" */
1385                         return;
1386         }
1387
1388         /*
1389          * delete the tuple
1390          */
1391 ldelete:;
1392         result = heap_delete(resultRelationDesc, tupleid,
1393                                                  &ctid,
1394                                                  estate->es_snapshot->curcid);
1395         switch (result)
1396         {
1397                 case HeapTupleSelfUpdated:
1398                         /* already deleted by self; nothing to do */
1399                         return;
1400
1401                 case HeapTupleMayBeUpdated:
1402                         break;
1403
1404                 case HeapTupleUpdated:
1405                         if (XactIsoLevel == XACT_SERIALIZABLE)
1406                                 elog(ERROR, "Can't serialize access due to concurrent update");
1407                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1408                         {
1409                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1410                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1411
1412                                 if (!TupIsNull(epqslot))
1413                                 {
1414                                         *tupleid = ctid;
1415                                         goto ldelete;
1416                                 }
1417                         }
1418                         /* tuple already deleted; nothing to do */
1419                         return;
1420
1421                 default:
1422                         elog(ERROR, "Unknown status %u from heap_delete", result);
1423                         return;
1424         }
1425
1426         IncrDeleted();
1427         (estate->es_processed)++;
1428
1429         /*
1430          * Note: Normally one would think that we have to delete index tuples
1431          * associated with the heap tuple now..
1432          *
1433          * ... but in POSTGRES, we have no need to do this because the vacuum
1434          * daemon automatically opens an index scan and deletes index tuples
1435          * when it finds deleted heap tuples. -cim 9/27/89
1436          */
1437
1438         /* AFTER ROW DELETE Triggers */
1439         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1440 }
1441
1442 /* ----------------------------------------------------------------
1443  *              ExecUpdate
1444  *
1445  *              note: we can't run UPDATE queries with transactions
1446  *              off because UPDATEs are actually INSERTs and our
1447  *              scan will mistakenly loop forever, updating the tuple
1448  *              it just inserted..      This should be fixed but until it
1449  *              is, we don't want to get stuck in an infinite loop
1450  *              which corrupts your database..
1451  * ----------------------------------------------------------------
1452  */
1453 static void
1454 ExecUpdate(TupleTableSlot *slot,
1455                    ItemPointer tupleid,
1456                    EState *estate)
1457 {
1458         HeapTuple       tuple;
1459         ResultRelInfo *resultRelInfo;
1460         Relation        resultRelationDesc;
1461         ItemPointerData ctid;
1462         int                     result;
1463         int                     numIndices;
1464
1465         /*
1466          * abort the operation if not running transactions
1467          */
1468         if (IsBootstrapProcessingMode())
1469         {
1470                 elog(WARNING, "ExecUpdate: UPDATE can't run without transactions");
1471                 return;
1472         }
1473
1474         /*
1475          * get the heap tuple out of the tuple table slot
1476          */
1477         tuple = slot->val;
1478
1479         /*
1480          * get information on the (current) result relation
1481          */
1482         resultRelInfo = estate->es_result_relation_info;
1483         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1484
1485         /* BEFORE ROW UPDATE Triggers */
1486         if (resultRelInfo->ri_TrigDesc &&
1487           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1488         {
1489                 HeapTuple       newtuple;
1490
1491                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1492                                                                                 tupleid, tuple,
1493                                                                                 estate->es_snapshot->curcid);
1494
1495                 if (newtuple == NULL)   /* "do nothing" */
1496                         return;
1497
1498                 if (newtuple != tuple)  /* modified by Trigger(s) */
1499                 {
1500                         /*
1501                          * Insert modified tuple into tuple table slot, replacing the
1502                          * original.  We assume that it was allocated in per-tuple
1503                          * memory context, and therefore will go away by itself. The
1504                          * tuple table slot should not try to clear it.
1505                          */
1506                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1507                         tuple = newtuple;
1508                 }
1509         }
1510
1511         /*
1512          * Check the constraints of the tuple
1513          *
1514          * If we generate a new candidate tuple after EvalPlanQual testing, we
1515          * must loop back here and recheck constraints.  (We don't need to
1516          * redo triggers, however.      If there are any BEFORE triggers then
1517          * trigger.c will have done mark4update to lock the correct tuple, so
1518          * there's no need to do them again.)
1519          */
1520 lreplace:;
1521         if (resultRelationDesc->rd_att->constr)
1522                 ExecConstraints("ExecUpdate", resultRelInfo, slot, estate);
1523
1524         /*
1525          * replace the heap tuple
1526          */
1527         result = heap_update(resultRelationDesc, tupleid, tuple,
1528                                                  &ctid,
1529                                                  estate->es_snapshot->curcid);
1530         switch (result)
1531         {
1532                 case HeapTupleSelfUpdated:
1533                         /* already deleted by self; nothing to do */
1534                         return;
1535
1536                 case HeapTupleMayBeUpdated:
1537                         break;
1538
1539                 case HeapTupleUpdated:
1540                         if (XactIsoLevel == XACT_SERIALIZABLE)
1541                                 elog(ERROR, "Can't serialize access due to concurrent update");
1542                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1543                         {
1544                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1545                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1546
1547                                 if (!TupIsNull(epqslot))
1548                                 {
1549                                         *tupleid = ctid;
1550                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1551                                         slot = ExecStoreTuple(tuple,
1552                                                                         estate->es_junkFilter->jf_resultSlot,
1553                                                                                   InvalidBuffer, true);
1554                                         goto lreplace;
1555                                 }
1556                         }
1557                         /* tuple already deleted; nothing to do */
1558                         return;
1559
1560                 default:
1561                         elog(ERROR, "Unknown status %u from heap_update", result);
1562                         return;
1563         }
1564
1565         IncrReplaced();
1566         (estate->es_processed)++;
1567
1568         /*
1569          * Note: instead of having to update the old index tuples associated
1570          * with the heap tuple, all we do is form and insert new index tuples.
1571          * This is because UPDATEs are actually DELETEs and INSERTs and index
1572          * tuple deletion is done automagically by the vacuum daemon. All we
1573          * do is insert new index tuples.  -cim 9/27/89
1574          */
1575
1576         /*
1577          * process indices
1578          *
1579          * heap_update updates a tuple in the base relation by invalidating it
1580          * and then inserting a new tuple to the relation.      As a side effect,
1581          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1582          * field.  So we now insert index tuples using the new tupleid stored
1583          * there.
1584          */
1585
1586         numIndices = resultRelInfo->ri_NumIndices;
1587         if (numIndices > 0)
1588                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1589
1590         /* AFTER ROW UPDATE Triggers */
1591         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1592 }
1593
1594 static char *
1595 ExecRelCheck(ResultRelInfo *resultRelInfo,
1596                          TupleTableSlot *slot, EState *estate)
1597 {
1598         Relation        rel = resultRelInfo->ri_RelationDesc;
1599         int                     ncheck = rel->rd_att->constr->num_check;
1600         ConstrCheck *check = rel->rd_att->constr->check;
1601         ExprContext *econtext;
1602         MemoryContext oldContext;
1603         List       *qual;
1604         int                     i;
1605
1606         /*
1607          * If first time through for this result relation, build expression
1608          * nodetrees for rel's constraint expressions.  Keep them in the
1609          * per-query memory context so they'll survive throughout the query.
1610          */
1611         if (resultRelInfo->ri_ConstraintExprs == NULL)
1612         {
1613                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1614                 resultRelInfo->ri_ConstraintExprs =
1615                         (List **) palloc(ncheck * sizeof(List *));
1616                 for (i = 0; i < ncheck; i++)
1617                 {
1618                         qual = (List *) stringToNode(check[i].ccbin);
1619                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1620                                 ExecPrepareExpr((Expr *) qual, estate);
1621                 }
1622                 MemoryContextSwitchTo(oldContext);
1623         }
1624
1625         /*
1626          * We will use the EState's per-tuple context for evaluating
1627          * constraint expressions (creating it if it's not already there).
1628          */
1629         econtext = GetPerTupleExprContext(estate);
1630
1631         /* Arrange for econtext's scan tuple to be the tuple under test */
1632         econtext->ecxt_scantuple = slot;
1633
1634         /* And evaluate the constraints */
1635         for (i = 0; i < ncheck; i++)
1636         {
1637                 qual = resultRelInfo->ri_ConstraintExprs[i];
1638
1639                 /*
1640                  * NOTE: SQL92 specifies that a NULL result from a constraint
1641                  * expression is not to be treated as a failure.  Therefore, tell
1642                  * ExecQual to return TRUE for NULL.
1643                  */
1644                 if (!ExecQual(qual, econtext, true))
1645                         return check[i].ccname;
1646         }
1647
1648         /* NULL result means no error */
1649         return (char *) NULL;
1650 }
1651
1652 void
1653 ExecConstraints(const char *caller, ResultRelInfo *resultRelInfo,
1654                                 TupleTableSlot *slot, EState *estate)
1655 {
1656         Relation        rel = resultRelInfo->ri_RelationDesc;
1657         HeapTuple       tuple = slot->val;
1658         TupleConstr *constr = rel->rd_att->constr;
1659
1660         Assert(constr);
1661
1662         if (constr->has_not_null)
1663         {
1664                 int                     natts = rel->rd_att->natts;
1665                 int                     attrChk;
1666
1667                 for (attrChk = 1; attrChk <= natts; attrChk++)
1668                 {
1669                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1670                                 heap_attisnull(tuple, attrChk))
1671                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1672                                          caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1673                 }
1674         }
1675
1676         if (constr->num_check > 0)
1677         {
1678                 char       *failed;
1679
1680                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1681                         elog(ERROR, "%s: rejected due to CHECK constraint \"%s\" on \"%s\"",
1682                                  caller, failed, RelationGetRelationName(rel));
1683         }
1684 }
1685
1686 /*
1687  * Check a modified tuple to see if we want to process its updated version
1688  * under READ COMMITTED rules.
1689  *
1690  * See backend/executor/README for some info about how this works.
1691  */
1692 TupleTableSlot *
1693 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1694 {
1695         evalPlanQual *epq;
1696         EState     *epqstate;
1697         Relation        relation;
1698         HeapTupleData tuple;
1699         HeapTuple       copyTuple = NULL;
1700         bool            endNode;
1701
1702         Assert(rti != 0);
1703
1704         /*
1705          * find relation containing target tuple
1706          */
1707         if (estate->es_result_relation_info != NULL &&
1708                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1709                 relation = estate->es_result_relation_info->ri_RelationDesc;
1710         else
1711         {
1712                 List       *l;
1713
1714                 relation = NULL;
1715                 foreach(l, estate->es_rowMark)
1716                 {
1717                         if (((execRowMark *) lfirst(l))->rti == rti)
1718                         {
1719                                 relation = ((execRowMark *) lfirst(l))->relation;
1720                                 break;
1721                         }
1722                 }
1723                 if (relation == NULL)
1724                         elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1725         }
1726
1727         /*
1728          * fetch tid tuple
1729          *
1730          * Loop here to deal with updated or busy tuples
1731          */
1732         tuple.t_self = *tid;
1733         for (;;)
1734         {
1735                 Buffer          buffer;
1736
1737                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1738                 {
1739                         TransactionId xwait = SnapshotDirty->xmax;
1740
1741                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1742                                 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1743
1744                         /*
1745                          * If tuple is being updated by other transaction then we have
1746                          * to wait for its commit/abort.
1747                          */
1748                         if (TransactionIdIsValid(xwait))
1749                         {
1750                                 ReleaseBuffer(buffer);
1751                                 XactLockTableWait(xwait);
1752                                 continue;
1753                         }
1754
1755                         /*
1756                          * We got tuple - now copy it for use by recheck query.
1757                          */
1758                         copyTuple = heap_copytuple(&tuple);
1759                         ReleaseBuffer(buffer);
1760                         break;
1761                 }
1762
1763                 /*
1764                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1765                  * Note that it's possible to get invalid SnapshotDirty->tid if
1766                  * tuple updated by this transaction. Have we to check this ?
1767                  */
1768                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1769                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1770                 {
1771                         /* updated, so look at the updated copy */
1772                         tuple.t_self = SnapshotDirty->tid;
1773                         continue;
1774                 }
1775
1776                 /*
1777                  * Deleted or updated by this transaction; forget it.
1778                  */
1779                 return NULL;
1780         }
1781
1782         /*
1783          * For UPDATE/DELETE we have to return tid of actual row we're
1784          * executing PQ for.
1785          */
1786         *tid = tuple.t_self;
1787
1788         /*
1789          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1790          */
1791         epq = estate->es_evalPlanQual;
1792         endNode = true;
1793
1794         if (epq != NULL && epq->rti == 0)
1795         {
1796                 /* Top PQ stack entry is idle, so re-use it */
1797                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1798                 epq->rti = rti;
1799                 endNode = false;
1800         }
1801
1802         /*
1803          * If this is request for another RTE - Ra, - then we have to check
1804          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1805          * updated again and we have to re-start old execution for Ra and
1806          * forget all what we done after Ra was suspended. Cool? -:))
1807          */
1808         if (epq != NULL && epq->rti != rti &&
1809                 epq->estate->es_evTuple[rti - 1] != NULL)
1810         {
1811                 do
1812                 {
1813                         evalPlanQual *oldepq;
1814
1815                         /* stop execution */
1816                         EvalPlanQualStop(epq);
1817                         /* pop previous PlanQual from the stack */
1818                         oldepq = epq->next;
1819                         Assert(oldepq && oldepq->rti != 0);
1820                         /* push current PQ to freePQ stack */
1821                         oldepq->free = epq;
1822                         epq = oldepq;
1823                         estate->es_evalPlanQual = epq;
1824                 } while (epq->rti != rti);
1825         }
1826
1827         /*
1828          * If we are requested for another RTE then we have to suspend
1829          * execution of current PlanQual and start execution for new one.
1830          */
1831         if (epq == NULL || epq->rti != rti)
1832         {
1833                 /* try to reuse plan used previously */
1834                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1835
1836                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1837                 {
1838                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1839                         newepq->free = NULL;
1840                         newepq->estate = NULL;
1841                         newepq->planstate = NULL;
1842                 }
1843                 else
1844                 {
1845                         /* recycle previously used PlanQual */
1846                         Assert(newepq->estate == NULL);
1847                         epq->free = NULL;
1848                 }
1849                 /* push current PQ to the stack */
1850                 newepq->next = epq;
1851                 epq = newepq;
1852                 estate->es_evalPlanQual = epq;
1853                 epq->rti = rti;
1854                 endNode = false;
1855         }
1856
1857         Assert(epq->rti == rti);
1858
1859         /*
1860          * Ok - we're requested for the same RTE.  Unfortunately we still have
1861          * to end and restart execution of the plan, because ExecReScan
1862          * wouldn't ensure that upper plan nodes would reset themselves.  We
1863          * could make that work if insertion of the target tuple were
1864          * integrated with the Param mechanism somehow, so that the upper plan
1865          * nodes know that their children's outputs have changed.
1866          *
1867          * Note that the stack of free evalPlanQual nodes is quite useless at
1868          * the moment, since it only saves us from pallocing/releasing the
1869          * evalPlanQual nodes themselves.  But it will be useful once we
1870          * implement ReScan instead of end/restart for re-using PlanQual nodes.
1871          */
1872         if (endNode)
1873         {
1874                 /* stop execution */
1875                 EvalPlanQualStop(epq);
1876         }
1877
1878         /*
1879          * Initialize new recheck query.
1880          *
1881          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need
1882          * to instead copy down changeable state from the top plan (including
1883          * es_result_relation_info, es_junkFilter) and reset locally changeable
1884          * state in the epq (including es_param_exec_vals, es_evTupleNull).
1885          */
1886         EvalPlanQualStart(epq, estate, epq->next);
1887
1888         /*
1889          * free old RTE' tuple, if any, and store target tuple where
1890          * relation's scan node will see it
1891          */
1892         epqstate = epq->estate;
1893         if (epqstate->es_evTuple[rti - 1] != NULL)
1894                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1895         epqstate->es_evTuple[rti - 1] = copyTuple;
1896
1897         return EvalPlanQualNext(estate);
1898 }
1899
1900 static TupleTableSlot *
1901 EvalPlanQualNext(EState *estate)
1902 {
1903         evalPlanQual *epq = estate->es_evalPlanQual;
1904         MemoryContext oldcontext;
1905         TupleTableSlot *slot;
1906
1907         Assert(epq->rti != 0);
1908
1909 lpqnext:;
1910         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1911         slot = ExecProcNode(epq->planstate);
1912         MemoryContextSwitchTo(oldcontext);
1913
1914         /*
1915          * No more tuples for this PQ. Continue previous one.
1916          */
1917         if (TupIsNull(slot))
1918         {
1919                 evalPlanQual *oldepq;
1920
1921                 /* stop execution */
1922                 EvalPlanQualStop(epq);
1923                 /* pop old PQ from the stack */
1924                 oldepq = epq->next;
1925                 if (oldepq == NULL)
1926                 {
1927                         /* this is the first (oldest) PQ - mark as free */
1928                         epq->rti = 0;
1929                         estate->es_useEvalPlan = false;
1930                         /* and continue Query execution */
1931                         return (NULL);
1932                 }
1933                 Assert(oldepq->rti != 0);
1934                 /* push current PQ to freePQ stack */
1935                 oldepq->free = epq;
1936                 epq = oldepq;
1937                 estate->es_evalPlanQual = epq;
1938                 goto lpqnext;
1939         }
1940
1941         return (slot);
1942 }
1943
1944 static void
1945 EndEvalPlanQual(EState *estate)
1946 {
1947         evalPlanQual *epq = estate->es_evalPlanQual;
1948
1949         if (epq->rti == 0)                      /* plans already shutdowned */
1950         {
1951                 Assert(epq->next == NULL);
1952                 return;
1953         }
1954
1955         for (;;)
1956         {
1957                 evalPlanQual *oldepq;
1958
1959                 /* stop execution */
1960                 EvalPlanQualStop(epq);
1961                 /* pop old PQ from the stack */
1962                 oldepq = epq->next;
1963                 if (oldepq == NULL)
1964                 {
1965                         /* this is the first (oldest) PQ - mark as free */
1966                         epq->rti = 0;
1967                         estate->es_useEvalPlan = false;
1968                         break;
1969                 }
1970                 Assert(oldepq->rti != 0);
1971                 /* push current PQ to freePQ stack */
1972                 oldepq->free = epq;
1973                 epq = oldepq;
1974                 estate->es_evalPlanQual = epq;
1975         }
1976 }
1977
1978 /*
1979  * Start execution of one level of PlanQual.
1980  *
1981  * This is a cut-down version of ExecutorStart(): we copy some state from
1982  * the top-level estate rather than initializing it fresh.
1983  */
1984 static void
1985 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
1986 {
1987         EState     *epqstate;
1988         int                     rtsize;
1989         MemoryContext oldcontext;
1990
1991         rtsize = length(estate->es_range_table);
1992
1993         epq->estate = epqstate = CreateExecutorState();
1994
1995         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
1996
1997         /*
1998          * The epqstates share the top query's copy of unchanging state such
1999          * as the snapshot, rangetable, result-rel info, and external Param info.
2000          * They need their own copies of local state, including a tuple table,
2001          * es_param_exec_vals, etc.
2002          */
2003         epqstate->es_direction = ForwardScanDirection;
2004         epqstate->es_snapshot = estate->es_snapshot;
2005         epqstate->es_range_table = estate->es_range_table;
2006         epqstate->es_result_relations = estate->es_result_relations;
2007         epqstate->es_num_result_relations = estate->es_num_result_relations;
2008         epqstate->es_result_relation_info = estate->es_result_relation_info;
2009         epqstate->es_junkFilter = estate->es_junkFilter;
2010         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2011         epqstate->es_param_list_info = estate->es_param_list_info;
2012         if (estate->es_topPlan->nParamExec > 0)
2013                 epqstate->es_param_exec_vals = (ParamExecData *)
2014                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2015         epqstate->es_rowMark = estate->es_rowMark;
2016         epqstate->es_instrument = estate->es_instrument;
2017         epqstate->es_force_oids = estate->es_force_oids;
2018         epqstate->es_topPlan = estate->es_topPlan;
2019         /*
2020          * Each epqstate must have its own es_evTupleNull state, but
2021          * all the stack entries share es_evTuple state.  This allows
2022          * sub-rechecks to inherit the value being examined by an
2023          * outer recheck.
2024          */
2025         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2026         if (priorepq == NULL)
2027                 /* first PQ stack entry */
2028                 epqstate->es_evTuple = (HeapTuple *)
2029                         palloc0(rtsize * sizeof(HeapTuple));
2030         else
2031                 /* later stack entries share the same storage */
2032                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2033
2034         epqstate->es_tupleTable =
2035                 ExecCreateTupleTable(estate->es_tupleTable->size);
2036
2037         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2038
2039         MemoryContextSwitchTo(oldcontext);
2040 }
2041
2042 /*
2043  * End execution of one level of PlanQual.
2044  *
2045  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2046  * of the normal cleanup, but *not* close result relations (which we are
2047  * just sharing from the outer query).
2048  */
2049 static void
2050 EvalPlanQualStop(evalPlanQual *epq)
2051 {
2052         EState     *epqstate = epq->estate;
2053         MemoryContext oldcontext;
2054
2055         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2056
2057         ExecEndNode(epq->planstate);
2058
2059         ExecDropTupleTable(epqstate->es_tupleTable, true);
2060         epqstate->es_tupleTable = NULL;
2061
2062         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2063         {
2064                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2065                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2066         }
2067
2068         MemoryContextSwitchTo(oldcontext);
2069
2070         FreeExecutorState(epqstate);
2071
2072         epq->estate = NULL;
2073         epq->planstate = NULL;
2074 }