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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 1.206 2003/05/05 17:57:47 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);
  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 *destfunc);
  76 static void ExecSelect(TupleTableSlot *slot,
  77                    DestReceiver *destfunc,
  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  * NB: the CurrentMemoryContext when this is called will become the parent
 108  * of the per-query context used for this Executor invocation.
 109  * ----------------------------------------------------------------
 110  */
 111 void
 112 ExecutorStart(QueryDesc *queryDesc)
 113 {
 114         EState     *estate;
 115         MemoryContext oldcontext;
 116
 117         /* sanity checks: queryDesc must not be started already */
 118         Assert(queryDesc != NULL);
 119         Assert(queryDesc->estate == NULL);
 120
 121         /*
 122          * Build EState, switch into per-query memory context for startup.
 123          */
 124         estate = CreateExecutorState();
 125         queryDesc->estate = estate;
 126
 127         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 128
 129         /*
 130          * Fill in parameters, if any, from queryDesc
 131          */
 132         estate->es_param_list_info = queryDesc->params;
 133
 134         if (queryDesc->plantree->nParamExec > 0)
 135                 estate->es_param_exec_vals = (ParamExecData *)
 136                         palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 137
 138         estate->es_instrument = queryDesc->doInstrument;
 139
 140         /*
 141          * Make our own private copy of the current query snapshot data.
 142          *
 143          * This "freezes" our idea of which tuples are good and which are not for
 144          * the life of this query, even if it outlives the current command and
 145          * current snapshot.
 146          */
 147         estate->es_snapshot = CopyQuerySnapshot();
 148
 149         /*
 150          * Initialize the plan state tree
 151          */
 152         InitPlan(queryDesc);
 153
 154         MemoryContextSwitchTo(oldcontext);
 155 }
 156
 157 /* ----------------------------------------------------------------
 158  *              ExecutorRun
 159  *
 160  *              This is the main routine of the executor module. It accepts
 161  *              the query descriptor from the traffic cop and executes the
 162  *              query plan.
 163  *
 164  *              ExecutorStart must have been called already.
 165  *
 166  *              If direction is NoMovementScanDirection then nothing is done
 167  *              except to start up/shut down the destination.  Otherwise,
 168  *              we retrieve up to 'count' tuples in the specified direction.
 169  *
 170  *              Note: count = 0 is interpreted as no portal limit, i.e., run to
 171  *              completion.
 172  *
 173  * ----------------------------------------------------------------
 174  */
 175 TupleTableSlot *
 176 ExecutorRun(QueryDesc *queryDesc,
 177                         ScanDirection direction, long count)
 178 {
 179         EState     *estate;
 180         CmdType         operation;
 181         CommandDest dest;
 182         DestReceiver *destfunc;
 183         TupleTableSlot *result;
 184         MemoryContext oldcontext;
 185
 186         /* sanity checks */
 187         Assert(queryDesc != NULL);
 188
 189         estate = queryDesc->estate;
 190
 191         Assert(estate != NULL);
 192
 193         /*
 194          * Switch into per-query memory context
 195          */
 196         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 197
 198         /*
 199          * extract information from the query descriptor and the query
 200          * feature.
 201          */
 202         operation = queryDesc->operation;
 203         dest = queryDesc->dest;
 204
 205         /*
 206          * If the transaction is read-only, we need to check if any writes
 207          * are planned to non-temporary tables.  This is done here at this
 208          * rather late stage so that we can handle EXPLAIN vs. EXPLAIN
 209          * ANALYZE easily.
 210          */
 211         ExecCheckXactReadOnly(queryDesc->parsetree, operation);
 212
 213         /*
 214          * startup tuple receiver
 215          */
 216         estate->es_processed = 0;
 217         estate->es_lastoid = InvalidOid;
 218
 219         destfunc = DestToFunction(dest);
 220         (*destfunc->setup) (destfunc, operation, queryDesc->portalName,
 221                                                 queryDesc->tupDesc);
 222
 223         /*
 224          * run plan
 225          */
 226         if (direction == NoMovementScanDirection)
 227                 result = NULL;
 228         else
 229                 result = ExecutePlan(estate,
 230                                                          queryDesc->planstate,
 231                                                          operation,
 232                                                          count,
 233                                                          direction,
 234                                                          destfunc);
 235
 236         /*
 237          * shutdown receiver
 238          */
 239         (*destfunc->cleanup) (destfunc);
 240
 241         MemoryContextSwitchTo(oldcontext);
 242
 243         return result;
 244 }
 245
 246 /* ----------------------------------------------------------------
 247  *              ExecutorEnd
 248  *
 249  *              This routine must be called at the end of execution of any
 250  *              query plan
 251  * ----------------------------------------------------------------
 252  */
 253 void
 254 ExecutorEnd(QueryDesc *queryDesc)
 255 {
 256         EState     *estate;
 257         MemoryContext oldcontext;
 258
 259         /* sanity checks */
 260         Assert(queryDesc != NULL);
 261
 262         estate = queryDesc->estate;
 263
 264         Assert(estate != NULL);
 265
 266         /*
 267          * Switch into per-query memory context to run ExecEndPlan
 268          */
 269         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 270
 271         ExecEndPlan(queryDesc->planstate, estate);
 272
 273         /*
 274          * Must switch out of context before destroying it
 275          */
 276         MemoryContextSwitchTo(oldcontext);
 277
 278         /*
 279          * Release EState and per-query memory context.  This should release
 280          * everything the executor has allocated.
 281          */
 282         FreeExecutorState(estate);
 283
 284         /* Reset queryDesc fields that no longer point to anything */
 285         queryDesc->tupDesc = NULL;
 286         queryDesc->estate = NULL;
 287         queryDesc->planstate = NULL;
 288 }
 289
 290 /* ----------------------------------------------------------------
 291  *              ExecutorRewind
 292  *
 293  *              This routine may be called on an open queryDesc to rewind it
 294  *              to the start.
 295  * ----------------------------------------------------------------
 296  */
 297 void
 298 ExecutorRewind(QueryDesc *queryDesc)
 299 {
 300         EState     *estate;
 301         MemoryContext oldcontext;
 302
 303         /* sanity checks */
 304         Assert(queryDesc != NULL);
 305
 306         estate = queryDesc->estate;
 307
 308         Assert(estate != NULL);
 309
 310         /* It's probably not sensible to rescan updating queries */
 311         Assert(queryDesc->operation == CMD_SELECT);
 312
 313         /*
 314          * Switch into per-query memory context
 315          */
 316         oldcontext = MemoryContextSwitchTo(estate->es_query_cxt);
 317
 318         /*
 319          * rescan plan
 320          */
 321         ExecReScan(queryDesc->planstate, NULL);
 322
 323         MemoryContextSwitchTo(oldcontext);
 324 }
 325
 326
 327 /*
 328  * ExecCheckRTPerms
 329  *              Check access permissions for all relations listed in a range table.
 330  */
 331 void
 332 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 333 {
 334         List       *lp;
 335
 336         foreach(lp, rangeTable)
 337         {
 338                 RangeTblEntry *rte = lfirst(lp);
 339
 340                 ExecCheckRTEPerms(rte, operation);
 341         }
 342 }
 343
 344 /*
 345  * ExecCheckRTEPerms
 346  *              Check access permissions for a single RTE.
 347  */
 348 static void
 349 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 350 {
 351         Oid                     relOid;
 352         AclId           userid;
 353         AclResult       aclcheck_result;
 354
 355         /*
 356          * If it's a subquery, recursively examine its rangetable.
 357          */
 358         if (rte->rtekind == RTE_SUBQUERY)
 359         {
 360                 ExecCheckRTPerms(rte->subquery->rtable, operation);
 361                 return;
 362         }
 363
 364         /*
 365          * Otherwise, only plain-relation RTEs need to be checked here.
 366          * Function RTEs are checked by init_fcache when the function is prepared
 367          * for execution. Join and special RTEs need no checks.
 368          */
 369         if (rte->rtekind != RTE_RELATION)
 370                 return;
 371
 372         relOid = rte->relid;
 373
 374         /*
 375          * userid to check as: current user unless we have a setuid
 376          * indication.
 377          *
 378          * Note: GetUserId() is presently fast enough that there's no harm in
 379          * calling it separately for each RTE.  If that stops being true, we
 380          * could call it once in ExecCheckRTPerms and pass the userid down
 381          * from there.  But for now, no need for the extra clutter.
 382          */
 383         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 384
 385 #define CHECK(MODE)             pg_class_aclcheck(relOid, userid, MODE)
 386
 387         if (rte->checkForRead)
 388         {
 389                 aclcheck_result = CHECK(ACL_SELECT);
 390                 if (aclcheck_result != ACLCHECK_OK)
 391                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 392         }
 393
 394         if (rte->checkForWrite)
 395         {
 396                 /*
 397                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 398                  * Right now we don't distinguish that from true update as far as
 399                  * permissions checks are concerned.
 400                  */
 401                 switch (operation)
 402                 {
 403                         case CMD_INSERT:
 404                                 aclcheck_result = CHECK(ACL_INSERT);
 405                                 break;
 406                         case CMD_SELECT:
 407                         case CMD_UPDATE:
 408                                 aclcheck_result = CHECK(ACL_UPDATE);
 409                                 break;
 410                         case CMD_DELETE:
 411                                 aclcheck_result = CHECK(ACL_DELETE);
 412                                 break;
 413                         default:
 414                                 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
 415                                          operation);
 416                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 417                                 break;
 418                 }
 419                 if (aclcheck_result != ACLCHECK_OK)
 420                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 421         }
 422 }
 423
 424 static void
 425 ExecCheckXactReadOnly(Query *parsetree, CmdType operation)
 426 {
 427         if (!XactReadOnly)
 428                 return;
 429
 430         /* CREATE TABLE AS or SELECT INTO */
 431         if (operation == CMD_SELECT && parsetree->into != NULL)
 432                 goto fail;
 433
 434         if (operation == CMD_DELETE || operation == CMD_INSERT
 435                 || operation == CMD_UPDATE)
 436         {
 437                 List *lp;
 438
 439                 foreach(lp, parsetree->rtable)
 440                 {
 441                         RangeTblEntry *rte = lfirst(lp);
 442
 443                         if (rte->rtekind != RTE_RELATION)
 444                                 continue;
 445
 446                         if (!rte->checkForWrite)
 447                                 continue;
 448
 449                         if (isTempNamespace(get_rel_namespace(rte->relid)))
 450                                 continue;
 451
 452                         goto fail;
 453                 }
 454         }
 455
 456         return;
 457
 458 fail:
 459         elog(ERROR, "transaction is read-only");
 460 }
 461
 462
 463 /* ----------------------------------------------------------------
 464  *              InitPlan
 465  *
 466  *              Initializes the query plan: open files, allocate storage
 467  *              and start up the rule manager
 468  * ----------------------------------------------------------------
 469  */
 470 static void
 471 InitPlan(QueryDesc *queryDesc)
 472 {
 473         CmdType         operation = queryDesc->operation;
 474         Query *parseTree = queryDesc->parsetree;
 475         Plan *plan = queryDesc->plantree;
 476         EState *estate = queryDesc->estate;
 477         PlanState  *planstate;
 478         List       *rangeTable;
 479         Relation        intoRelationDesc;
 480         bool            do_select_into;
 481         TupleDesc       tupType;
 482
 483         /*
 484          * Do permissions checks.  It's sufficient to examine the query's
 485          * top rangetable here --- subplan RTEs will be checked during
 486          * ExecInitSubPlan().
 487          */
 488         ExecCheckRTPerms(parseTree->rtable, operation);
 489
 490         /*
 491          * get information from query descriptor
 492          */
 493         rangeTable = parseTree->rtable;
 494
 495         /*
 496          * initialize the node's execution state
 497          */
 498         estate->es_range_table = rangeTable;
 499
 500         /*
 501          * if there is a result relation, initialize result relation stuff
 502          */
 503         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 504         {
 505                 List       *resultRelations = parseTree->resultRelations;
 506                 int                     numResultRelations;
 507                 ResultRelInfo *resultRelInfos;
 508
 509                 if (resultRelations != NIL)
 510                 {
 511                         /*
 512                          * Multiple result relations (due to inheritance)
 513                          * parseTree->resultRelations identifies them all
 514                          */
 515                         ResultRelInfo *resultRelInfo;
 516
 517                         numResultRelations = length(resultRelations);
 518                         resultRelInfos = (ResultRelInfo *)
 519                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 520                         resultRelInfo = resultRelInfos;
 521                         while (resultRelations != NIL)
 522                         {
 523                                 initResultRelInfo(resultRelInfo,
 524                                                                   lfirsti(resultRelations),
 525                                                                   rangeTable,
 526                                                                   operation);
 527                                 resultRelInfo++;
 528                                 resultRelations = lnext(resultRelations);
 529                         }
 530                 }
 531                 else
 532                 {
 533                         /*
 534                          * Single result relation identified by
 535                          * parseTree->resultRelation
 536                          */
 537                         numResultRelations = 1;
 538                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 539                         initResultRelInfo(resultRelInfos,
 540                                                           parseTree->resultRelation,
 541                                                           rangeTable,
 542                                                           operation);
 543                 }
 544
 545                 estate->es_result_relations = resultRelInfos;
 546                 estate->es_num_result_relations = numResultRelations;
 547                 /* Initialize to first or only result rel */
 548                 estate->es_result_relation_info = resultRelInfos;
 549         }
 550         else
 551         {
 552                 /*
 553                  * if no result relation, then set state appropriately
 554                  */
 555                 estate->es_result_relations = NULL;
 556                 estate->es_num_result_relations = 0;
 557                 estate->es_result_relation_info = NULL;
 558         }
 559
 560         /*
 561          * Detect whether we're doing SELECT INTO.  If so, set the force_oids
 562          * flag appropriately so that the plan tree will be initialized with
 563          * the correct tuple descriptors.
 564          */
 565         do_select_into = false;
 566
 567         if (operation == CMD_SELECT && parseTree->into != NULL)
 568         {
 569                 do_select_into = true;
 570                 /*
 571                  * For now, always create OIDs in SELECT INTO; this is for backwards
 572                  * compatibility with pre-7.3 behavior.  Eventually we might want
 573                  * to allow the user to choose.
 574                  */
 575                 estate->es_force_oids = true;
 576         }
 577
 578         /*
 579          * Have to lock relations selected for update
 580          */
 581         estate->es_rowMark = NIL;
 582         if (parseTree->rowMarks != NIL)
 583         {
 584                 List       *l;
 585
 586                 foreach(l, parseTree->rowMarks)
 587                 {
 588                         Index           rti = lfirsti(l);
 589                         Oid                     relid = getrelid(rti, rangeTable);
 590                         Relation        relation;
 591                         execRowMark *erm;
 592
 593                         relation = heap_open(relid, RowShareLock);
 594                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 595                         erm->relation = relation;
 596                         erm->rti = rti;
 597                         snprintf(erm->resname, sizeof(erm->resname), "ctid%u", rti);
 598                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 599                 }
 600         }
 601
 602         /*
 603          * initialize the executor "tuple" table.  We need slots for all the
 604          * plan nodes, plus possibly output slots for the junkfilter(s). At
 605          * this point we aren't sure if we need junkfilters, so just add slots
 606          * for them unconditionally.
 607          */
 608         {
 609                 int                     nSlots = ExecCountSlotsNode(plan);
 610
 611                 if (parseTree->resultRelations != NIL)
 612                         nSlots += length(parseTree->resultRelations);
 613                 else
 614                         nSlots += 1;
 615                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 616         }
 617
 618         /* mark EvalPlanQual not active */
 619         estate->es_topPlan = plan;
 620         estate->es_evalPlanQual = NULL;
 621         estate->es_evTupleNull = NULL;
 622         estate->es_evTuple = NULL;
 623         estate->es_useEvalPlan = false;
 624
 625         /*
 626          * initialize the private state information for all the nodes in the
 627          * query tree.  This opens files, allocates storage and leaves us
 628          * ready to start processing tuples.
 629          */
 630         planstate = ExecInitNode(plan, estate);
 631
 632         /*
 633          * Get the tuple descriptor describing the type of tuples to return.
 634          * (this is especially important if we are creating a relation with
 635          * "SELECT INTO")
 636          */
 637         tupType = ExecGetResultType(planstate);
 638
 639         /*
 640          * Initialize the junk filter if needed.  SELECT and INSERT queries need a
 641          * filter if there are any junk attrs in the tlist.  INSERT and SELECT
 642          * INTO also need a filter if the top plan node is a scan node that's not
 643          * doing projection (else we'll be scribbling on the scan tuple!)  UPDATE
 644          * and DELETE always need a filter, since there's always a junk 'ctid'
 645          * attribute present --- no need to look first.
 646          */
 647         {
 648                 bool            junk_filter_needed = false;
 649                 List       *tlist;
 650
 651                 switch (operation)
 652                 {
 653                         case CMD_SELECT:
 654                         case CMD_INSERT:
 655                                 foreach(tlist, plan->targetlist)
 656                                 {
 657                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 658
 659                                         if (tle->resdom->resjunk)
 660                                         {
 661                                                 junk_filter_needed = true;
 662                                                 break;
 663                                         }
 664                                 }
 665                                 if (!junk_filter_needed &&
 666                                         (operation == CMD_INSERT || do_select_into))
 667                                 {
 668                                         if (IsA(planstate, SeqScanState) ||
 669                                                 IsA(planstate, IndexScanState) ||
 670                                                 IsA(planstate, TidScanState) ||
 671                                                 IsA(planstate, SubqueryScanState) ||
 672                                                 IsA(planstate, FunctionScanState))
 673                                         {
 674                                                 if (planstate->ps_ProjInfo == NULL)
 675                                                         junk_filter_needed = true;
 676                                         }
 677                                 }
 678                                 break;
 679                         case CMD_UPDATE:
 680                         case CMD_DELETE:
 681                                 junk_filter_needed = true;
 682                                 break;
 683                         default:
 684                                 break;
 685                 }
 686
 687                 if (junk_filter_needed)
 688                 {
 689                         /*
 690                          * If there are multiple result relations, each one needs its
 691                          * own junk filter.  Note this is only possible for
 692                          * UPDATE/DELETE, so we can't be fooled by some needing a
 693                          * filter and some not.
 694                          */
 695                         if (parseTree->resultRelations != NIL)
 696                         {
 697                                 PlanState **appendplans;
 698                                 int                     as_nplans;
 699                                 ResultRelInfo *resultRelInfo;
 700                                 int                     i;
 701
 702                                 /* Top plan had better be an Append here. */
 703                                 Assert(IsA(plan, Append));
 704                                 Assert(((Append *) plan)->isTarget);
 705                                 Assert(IsA(planstate, AppendState));
 706                                 appendplans = ((AppendState *) planstate)->appendplans;
 707                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 708                                 Assert(as_nplans == estate->es_num_result_relations);
 709                                 resultRelInfo = estate->es_result_relations;
 710                                 for (i = 0; i < as_nplans; i++)
 711                                 {
 712                                         PlanState  *subplan = appendplans[i];
 713                                         JunkFilter *j;
 714
 715                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 716                                                                                    ExecGetResultType(subplan),
 717                                                           ExecAllocTableSlot(estate->es_tupleTable));
 718                                         resultRelInfo->ri_junkFilter = j;
 719                                         resultRelInfo++;
 720                                 }
 721
 722                                 /*
 723                                  * Set active junkfilter too; at this point ExecInitAppend
 724                                  * has already selected an active result relation...
 725                                  */
 726                                 estate->es_junkFilter =
 727                                         estate->es_result_relation_info->ri_junkFilter;
 728                         }
 729                         else
 730                         {
 731                                 /* Normal case with just one JunkFilter */
 732                                 JunkFilter *j;
 733
 734                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 735                                                                            tupType,
 736                                                           ExecAllocTableSlot(estate->es_tupleTable));
 737                                 estate->es_junkFilter = j;
 738                                 if (estate->es_result_relation_info)
 739                                         estate->es_result_relation_info->ri_junkFilter = j;
 740
 741                                 /* For SELECT, want to return the cleaned tuple type */
 742                                 if (operation == CMD_SELECT)
 743                                         tupType = j->jf_cleanTupType;
 744                         }
 745                 }
 746                 else
 747                         estate->es_junkFilter = NULL;
 748         }
 749
 750         /*
 751          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 752          * till now so we have the "clean" result tuple type to create the
 753          * new table from.
 754          */
 755         intoRelationDesc = (Relation) NULL;
 756
 757         if (do_select_into)
 758         {
 759                 char       *intoName;
 760                 Oid                     namespaceId;
 761                 AclResult       aclresult;
 762                 Oid                     intoRelationId;
 763                 TupleDesc       tupdesc;
 764
 765                 /*
 766                  * find namespace to create in, check permissions
 767                  */
 768                 intoName = parseTree->into->relname;
 769                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 770
 771                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 772                                                                                   ACL_CREATE);
 773                 if (aclresult != ACLCHECK_OK)
 774                         aclcheck_error(aclresult, get_namespace_name(namespaceId));
 775
 776                 /*
 777                  * have to copy tupType to get rid of constraints
 778                  */
 779                 tupdesc = CreateTupleDescCopy(tupType);
 780
 781                 intoRelationId = heap_create_with_catalog(intoName,
 782                                                                                                   namespaceId,
 783                                                                                                   tupdesc,
 784                                                                                                   RELKIND_RELATION,
 785                                                                                                   false,
 786                                                                                                   ONCOMMIT_NOOP,
 787                                                                                                   allowSystemTableMods);
 788
 789                 FreeTupleDesc(tupdesc);
 790
 791                 /*
 792                  * Advance command counter so that the newly-created
 793                  * relation's catalog tuples will be visible to heap_open.
 794                  */
 795                 CommandCounterIncrement();
 796
 797                 /*
 798                  * If necessary, create a TOAST table for the into
 799                  * relation. Note that AlterTableCreateToastTable ends
 800                  * with CommandCounterIncrement(), so that the TOAST table
 801                  * will be visible for insertion.
 802                  */
 803                 AlterTableCreateToastTable(intoRelationId, true);
 804
 805                 /*
 806                  * And open the constructed table for writing.
 807                  */
 808                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 809         }
 810
 811         estate->es_into_relation_descriptor = intoRelationDesc;
 812
 813         queryDesc->tupDesc = tupType;
 814         queryDesc->planstate = planstate;
 815 }
 816
 817 /*
 818  * Initialize ResultRelInfo data for one result relation
 819  */
 820 static void
 821 initResultRelInfo(ResultRelInfo *resultRelInfo,
 822                                   Index resultRelationIndex,
 823                                   List *rangeTable,
 824                                   CmdType operation)
 825 {
 826         Oid                     resultRelationOid;
 827         Relation        resultRelationDesc;
 828
 829         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 830         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 831
 832         switch (resultRelationDesc->rd_rel->relkind)
 833         {
 834                 case RELKIND_SEQUENCE:
 835                         elog(ERROR, "You can't change sequence relation %s",
 836                                  RelationGetRelationName(resultRelationDesc));
 837                         break;
 838                 case RELKIND_TOASTVALUE:
 839                         elog(ERROR, "You can't change toast relation %s",
 840                                  RelationGetRelationName(resultRelationDesc));
 841                         break;
 842                 case RELKIND_VIEW:
 843                         elog(ERROR, "You can't change view relation %s",
 844                                  RelationGetRelationName(resultRelationDesc));
 845                         break;
 846         }
 847
 848         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 849         resultRelInfo->type = T_ResultRelInfo;
 850         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 851         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 852         resultRelInfo->ri_NumIndices = 0;
 853         resultRelInfo->ri_IndexRelationDescs = NULL;
 854         resultRelInfo->ri_IndexRelationInfo = NULL;
 855         /* make a copy so as not to depend on relcache info not changing... */
 856         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 857         resultRelInfo->ri_TrigFunctions = NULL;
 858         resultRelInfo->ri_ConstraintExprs = NULL;
 859         resultRelInfo->ri_junkFilter = NULL;
 860
 861         /*
 862          * If there are indices on the result relation, open them and save
 863          * descriptors in the result relation info, so that we can add new
 864          * index entries for the tuples we add/update.  We need not do this
 865          * for a DELETE, however, since deletion doesn't affect indexes.
 866          */
 867         if (resultRelationDesc->rd_rel->relhasindex &&
 868                 operation != CMD_DELETE)
 869                 ExecOpenIndices(resultRelInfo);
 870 }
 871
 872 /* ----------------------------------------------------------------
 873  *              ExecEndPlan
 874  *
 875  *              Cleans up the query plan -- closes files and frees up storage
 876  *
 877  * NOTE: we are no longer very worried about freeing storage per se
 878  * in this code; FreeExecutorState should be guaranteed to release all
 879  * memory that needs to be released.  What we are worried about doing
 880  * is closing relations and dropping buffer pins.  Thus, for example,
 881  * tuple tables must be cleared or dropped to ensure pins are released.
 882  * ----------------------------------------------------------------
 883  */
 884 void
 885 ExecEndPlan(PlanState *planstate, EState *estate)
 886 {
 887         ResultRelInfo *resultRelInfo;
 888         int                     i;
 889         List       *l;
 890
 891         /*
 892          * shut down any PlanQual processing we were doing
 893          */
 894         if (estate->es_evalPlanQual != NULL)
 895                 EndEvalPlanQual(estate);
 896
 897         /*
 898          * shut down the node-type-specific query processing
 899          */
 900         ExecEndNode(planstate);
 901
 902         /*
 903          * destroy the executor "tuple" table.
 904          */
 905         ExecDropTupleTable(estate->es_tupleTable, true);
 906         estate->es_tupleTable = NULL;
 907
 908         /*
 909          * close the result relation(s) if any, but hold locks until xact
 910          * commit.
 911          */
 912         resultRelInfo = estate->es_result_relations;
 913         for (i = estate->es_num_result_relations; i > 0; i--)
 914         {
 915                 /* Close indices and then the relation itself */
 916                 ExecCloseIndices(resultRelInfo);
 917                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 918                 resultRelInfo++;
 919         }
 920
 921         /*
 922          * close the "into" relation if necessary, again keeping lock
 923          */
 924         if (estate->es_into_relation_descriptor != NULL)
 925                 heap_close(estate->es_into_relation_descriptor, NoLock);
 926
 927         /*
 928          * close any relations selected FOR UPDATE, again keeping locks
 929          */
 930         foreach(l, estate->es_rowMark)
 931         {
 932                 execRowMark *erm = lfirst(l);
 933
 934                 heap_close(erm->relation, NoLock);
 935         }
 936 }
 937
 938 /* ----------------------------------------------------------------
 939  *              ExecutePlan
 940  *
 941  *              processes the query plan to retrieve 'numberTuples' tuples in the
 942  *              direction specified.
 943  *
 944  *              Retrieves all tuples if numberTuples is 0
 945  *
 946  *              result is either a slot containing the last tuple in the case
 947  *              of a SELECT or NULL otherwise.
 948  *
 949  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 950  * user can see it
 951  * ----------------------------------------------------------------
 952  */
 953 static TupleTableSlot *
 954 ExecutePlan(EState *estate,
 955                         PlanState *planstate,
 956                         CmdType operation,
 957                         long numberTuples,
 958                         ScanDirection direction,
 959                         DestReceiver *destfunc)
 960 {
 961         JunkFilter                      *junkfilter;
 962         TupleTableSlot          *slot;
 963         ItemPointer                      tupleid = NULL;
 964         ItemPointerData          tuple_ctid;
 965         long                             current_tuple_count;
 966         TupleTableSlot          *result;
 967
 968         /*
 969          * initialize local variables
 970          */
 971         slot = NULL;
 972         current_tuple_count = 0;
 973         result = NULL;
 974
 975         /*
 976          * Set the direction.
 977          */
 978         estate->es_direction = direction;
 979
 980         /*
 981          * Process BEFORE EACH STATEMENT triggers
 982          */
 983         switch (operation)
 984         {
 985                 case CMD_UPDATE:
 986                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
 987                         break;
 988                 case CMD_DELETE:
 989                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
 990                         break;
 991                 case CMD_INSERT:
 992                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
 993                         break;
 994                 default:
 995                         /* do nothing */
 996                         break;
 997         }
 998
 999         /*
1000          * Loop until we've processed the proper number of tuples from the
1001          * plan.
1002          */
1003
1004         for (;;)
1005         {
1006                 /* Reset the per-output-tuple exprcontext */
1007                 ResetPerTupleExprContext(estate);
1008
1009                 /*
1010                  * Execute the plan and obtain a tuple
1011                  */
1012 lnext:  ;
1013                 if (estate->es_useEvalPlan)
1014                 {
1015                         slot = EvalPlanQualNext(estate);
1016                         if (TupIsNull(slot))
1017                                 slot = ExecProcNode(planstate);
1018                 }
1019                 else
1020                         slot = ExecProcNode(planstate);
1021
1022                 /*
1023                  * if the tuple is null, then we assume there is nothing more to
1024                  * process so we just return null...
1025                  */
1026                 if (TupIsNull(slot))
1027                 {
1028                         result = NULL;
1029                         break;
1030                 }
1031
1032                 /*
1033                  * if we have a junk filter, then project a new tuple with the
1034                  * junk removed.
1035                  *
1036                  * Store this new "clean" tuple in the junkfilter's resultSlot.
1037                  * (Formerly, we stored it back over the "dirty" tuple, which is
1038                  * WRONG because that tuple slot has the wrong descriptor.)
1039                  *
1040                  * Also, extract all the junk information we need.
1041                  */
1042                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
1043                 {
1044                         Datum           datum;
1045                         HeapTuple       newTuple;
1046                         bool            isNull;
1047
1048                         /*
1049                          * extract the 'ctid' junk attribute.
1050                          */
1051                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1052                         {
1053                                 if (!ExecGetJunkAttribute(junkfilter,
1054                                                                                   slot,
1055                                                                                   "ctid",
1056                                                                                   &datum,
1057                                                                                   &isNull))
1058                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
1059
1060                                 /* shouldn't ever get a null result... */
1061                                 if (isNull)
1062                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
1063
1064                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1065                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1066                                                                                  * ctid!! */
1067                                 tupleid = &tuple_ctid;
1068                         }
1069                         else if (estate->es_rowMark != NIL)
1070                         {
1071                                 List       *l;
1072
1073                 lmark:  ;
1074                                 foreach(l, estate->es_rowMark)
1075                                 {
1076                                         execRowMark *erm = lfirst(l);
1077                                         Buffer          buffer;
1078                                         HeapTupleData tuple;
1079                                         TupleTableSlot *newSlot;
1080                                         int                     test;
1081
1082                                         if (!ExecGetJunkAttribute(junkfilter,
1083                                                                                           slot,
1084                                                                                           erm->resname,
1085                                                                                           &datum,
1086                                                                                           &isNull))
1087                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1088                                                          erm->resname);
1089
1090                                         /* shouldn't ever get a null result... */
1091                                         if (isNull)
1092                                                 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1093                                                          erm->resname);
1094
1095                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1096                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1097                                                                                         estate->es_snapshot->curcid);
1098                                         ReleaseBuffer(buffer);
1099                                         switch (test)
1100                                         {
1101                                                 case HeapTupleSelfUpdated:
1102                                                         /* treat it as deleted; do not process */
1103                                                         goto lnext;
1104
1105                                                 case HeapTupleMayBeUpdated:
1106                                                         break;
1107
1108                                                 case HeapTupleUpdated:
1109                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1110                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1111                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1112                                                                   (ItemPointer) DatumGetPointer(datum))))
1113                                                         {
1114                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1115                                                                 if (!(TupIsNull(newSlot)))
1116                                                                 {
1117                                                                         slot = newSlot;
1118                                                                         estate->es_useEvalPlan = true;
1119                                                                         goto lmark;
1120                                                                 }
1121                                                         }
1122
1123                                                         /*
1124                                                          * if tuple was deleted or PlanQual failed for
1125                                                          * updated tuple - we must not return this
1126                                                          * tuple!
1127                                                          */
1128                                                         goto lnext;
1129
1130                                                 default:
1131                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1132                                                         return (NULL);
1133                                         }
1134                                 }
1135                         }
1136
1137                         /*
1138                          * Finally create a new "clean" tuple with all junk attributes
1139                          * removed
1140                          */
1141                         newTuple = ExecRemoveJunk(junkfilter, slot);
1142
1143                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1144                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1145                                                                   InvalidBuffer,                /* this tuple has no
1146                                                                                                                  * buffer */
1147                                                                   true);                /* tuple should be pfreed */
1148                 }
1149
1150                 /*
1151                  * now that we have a tuple, do the appropriate thing with it..
1152                  * either return it to the user, add it to a relation someplace,
1153                  * delete it from a relation, or modify some of its attributes.
1154                  */
1155                 switch (operation)
1156                 {
1157                         case CMD_SELECT:
1158                                 ExecSelect(slot,        /* slot containing tuple */
1159                                                    destfunc,    /* destination's tuple-receiver
1160                                                                                  * 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 *destfunc,
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         if (estate->es_into_relation_descriptor != NULL)
1250         {
1251                 heap_insert(estate->es_into_relation_descriptor, tuple,
1252                                         estate->es_snapshot->curcid);
1253                 IncrAppended();
1254         }
1255
1256         /*
1257          * send the tuple to the front end (or the screen)
1258          */
1259         (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1260         IncrRetrieved();
1261         (estate->es_processed)++;
1262 }
1263
1264 /* ----------------------------------------------------------------
1265  *              ExecInsert
1266  *
1267  *              INSERTs are trickier.. we have to insert the tuple into
1268  *              the base relation and insert appropriate tuples into the
1269  *              index relations.
1270  * ----------------------------------------------------------------
1271  */
1272 static void
1273 ExecInsert(TupleTableSlot *slot,
1274                    ItemPointer tupleid,
1275                    EState *estate)
1276 {
1277         HeapTuple       tuple;
1278         ResultRelInfo *resultRelInfo;
1279         Relation        resultRelationDesc;
1280         int                     numIndices;
1281         Oid                     newId;
1282
1283         /*
1284          * get the heap tuple out of the tuple table slot
1285          */
1286         tuple = slot->val;
1287
1288         /*
1289          * get information on the (current) result relation
1290          */
1291         resultRelInfo = estate->es_result_relation_info;
1292         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1293
1294         /* BEFORE ROW INSERT Triggers */
1295         if (resultRelInfo->ri_TrigDesc &&
1296                 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1297         {
1298                 HeapTuple       newtuple;
1299
1300                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1301
1302                 if (newtuple == NULL)   /* "do nothing" */
1303                         return;
1304
1305                 if (newtuple != tuple)  /* modified by Trigger(s) */
1306                 {
1307                         /*
1308                          * Insert modified tuple into tuple table slot, replacing the
1309                          * original.  We assume that it was allocated in per-tuple
1310                          * memory context, and therefore will go away by itself. The
1311                          * tuple table slot should not try to clear it.
1312                          */
1313                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1314                         tuple = newtuple;
1315                 }
1316         }
1317
1318         /*
1319          * Check the constraints of the tuple
1320          */
1321         if (resultRelationDesc->rd_att->constr)
1322                 ExecConstraints("ExecInsert", resultRelInfo, slot, estate);
1323
1324         /*
1325          * insert the tuple
1326          */
1327         newId = heap_insert(resultRelationDesc, tuple,
1328                                                 estate->es_snapshot->curcid);
1329
1330         IncrAppended();
1331         (estate->es_processed)++;
1332         estate->es_lastoid = newId;
1333         setLastTid(&(tuple->t_self));
1334
1335         /*
1336          * process indices
1337          *
1338          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1339          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1340          * field.
1341          */
1342         numIndices = resultRelInfo->ri_NumIndices;
1343         if (numIndices > 0)
1344                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1345
1346         /* AFTER ROW INSERT Triggers */
1347         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1348 }
1349
1350 /* ----------------------------------------------------------------
1351  *              ExecDelete
1352  *
1353  *              DELETE is like UPDATE, we delete the tuple and its
1354  *              index tuples.
1355  * ----------------------------------------------------------------
1356  */
1357 static void
1358 ExecDelete(TupleTableSlot *slot,
1359                    ItemPointer tupleid,
1360                    EState *estate)
1361 {
1362         ResultRelInfo *resultRelInfo;
1363         Relation        resultRelationDesc;
1364         ItemPointerData ctid;
1365         int                     result;
1366
1367         /*
1368          * get information on the (current) result relation
1369          */
1370         resultRelInfo = estate->es_result_relation_info;
1371         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1372
1373         /* BEFORE ROW DELETE Triggers */
1374         if (resultRelInfo->ri_TrigDesc &&
1375           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1376         {
1377                 bool            dodelete;
1378
1379                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid,
1380                                                                                 estate->es_snapshot->curcid);
1381
1382                 if (!dodelete)                  /* "do nothing" */
1383                         return;
1384         }
1385
1386         /*
1387          * delete the tuple
1388          */
1389 ldelete:;
1390         result = heap_delete(resultRelationDesc, tupleid,
1391                                                  &ctid,
1392                                                  estate->es_snapshot->curcid);
1393         switch (result)
1394         {
1395                 case HeapTupleSelfUpdated:
1396                         /* already deleted by self; nothing to do */
1397                         return;
1398
1399                 case HeapTupleMayBeUpdated:
1400                         break;
1401
1402                 case HeapTupleUpdated:
1403                         if (XactIsoLevel == XACT_SERIALIZABLE)
1404                                 elog(ERROR, "Can't serialize access due to concurrent update");
1405                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1406                         {
1407                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1408                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1409
1410                                 if (!TupIsNull(epqslot))
1411                                 {
1412                                         *tupleid = ctid;
1413                                         goto ldelete;
1414                                 }
1415                         }
1416                         /* tuple already deleted; nothing to do */
1417                         return;
1418
1419                 default:
1420                         elog(ERROR, "Unknown status %u from heap_delete", result);
1421                         return;
1422         }
1423
1424         IncrDeleted();
1425         (estate->es_processed)++;
1426
1427         /*
1428          * Note: Normally one would think that we have to delete index tuples
1429          * associated with the heap tuple now..
1430          *
1431          * ... but in POSTGRES, we have no need to do this because the vacuum
1432          * daemon automatically opens an index scan and deletes index tuples
1433          * when it finds deleted heap tuples. -cim 9/27/89
1434          */
1435
1436         /* AFTER ROW DELETE Triggers */
1437         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1438 }
1439
1440 /* ----------------------------------------------------------------
1441  *              ExecUpdate
1442  *
1443  *              note: we can't run UPDATE queries with transactions
1444  *              off because UPDATEs are actually INSERTs and our
1445  *              scan will mistakenly loop forever, updating the tuple
1446  *              it just inserted..      This should be fixed but until it
1447  *              is, we don't want to get stuck in an infinite loop
1448  *              which corrupts your database..
1449  * ----------------------------------------------------------------
1450  */
1451 static void
1452 ExecUpdate(TupleTableSlot *slot,
1453                    ItemPointer tupleid,
1454                    EState *estate)
1455 {
1456         HeapTuple       tuple;
1457         ResultRelInfo *resultRelInfo;
1458         Relation        resultRelationDesc;
1459         ItemPointerData ctid;
1460         int                     result;
1461         int                     numIndices;
1462
1463         /*
1464          * abort the operation if not running transactions
1465          */
1466         if (IsBootstrapProcessingMode())
1467         {
1468                 elog(WARNING, "ExecUpdate: UPDATE can't run without transactions");
1469                 return;
1470         }
1471
1472         /*
1473          * get the heap tuple out of the tuple table slot
1474          */
1475         tuple = slot->val;
1476
1477         /*
1478          * get information on the (current) result relation
1479          */
1480         resultRelInfo = estate->es_result_relation_info;
1481         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1482
1483         /* BEFORE ROW UPDATE Triggers */
1484         if (resultRelInfo->ri_TrigDesc &&
1485           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1486         {
1487                 HeapTuple       newtuple;
1488
1489                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1490                                                                                 tupleid, tuple,
1491                                                                                 estate->es_snapshot->curcid);
1492
1493                 if (newtuple == NULL)   /* "do nothing" */
1494                         return;
1495
1496                 if (newtuple != tuple)  /* modified by Trigger(s) */
1497                 {
1498                         /*
1499                          * Insert modified tuple into tuple table slot, replacing the
1500                          * original.  We assume that it was allocated in per-tuple
1501                          * memory context, and therefore will go away by itself. The
1502                          * tuple table slot should not try to clear it.
1503                          */
1504                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1505                         tuple = newtuple;
1506                 }
1507         }
1508
1509         /*
1510          * Check the constraints of the tuple
1511          *
1512          * If we generate a new candidate tuple after EvalPlanQual testing, we
1513          * must loop back here and recheck constraints.  (We don't need to
1514          * redo triggers, however.      If there are any BEFORE triggers then
1515          * trigger.c will have done mark4update to lock the correct tuple, so
1516          * there's no need to do them again.)
1517          */
1518 lreplace:;
1519         if (resultRelationDesc->rd_att->constr)
1520                 ExecConstraints("ExecUpdate", resultRelInfo, slot, estate);
1521
1522         /*
1523          * replace the heap tuple
1524          */
1525         result = heap_update(resultRelationDesc, tupleid, tuple,
1526                                                  &ctid,
1527                                                  estate->es_snapshot->curcid);
1528         switch (result)
1529         {
1530                 case HeapTupleSelfUpdated:
1531                         /* already deleted by self; nothing to do */
1532                         return;
1533
1534                 case HeapTupleMayBeUpdated:
1535                         break;
1536
1537                 case HeapTupleUpdated:
1538                         if (XactIsoLevel == XACT_SERIALIZABLE)
1539                                 elog(ERROR, "Can't serialize access due to concurrent update");
1540                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1541                         {
1542                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1543                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1544
1545                                 if (!TupIsNull(epqslot))
1546                                 {
1547                                         *tupleid = ctid;
1548                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1549                                         slot = ExecStoreTuple(tuple,
1550                                                                         estate->es_junkFilter->jf_resultSlot,
1551                                                                                   InvalidBuffer, true);
1552                                         goto lreplace;
1553                                 }
1554                         }
1555                         /* tuple already deleted; nothing to do */
1556                         return;
1557
1558                 default:
1559                         elog(ERROR, "Unknown status %u from heap_update", result);
1560                         return;
1561         }
1562
1563         IncrReplaced();
1564         (estate->es_processed)++;
1565
1566         /*
1567          * Note: instead of having to update the old index tuples associated
1568          * with the heap tuple, all we do is form and insert new index tuples.
1569          * This is because UPDATEs are actually DELETEs and INSERTs and index
1570          * tuple deletion is done automagically by the vacuum daemon. All we
1571          * do is insert new index tuples.  -cim 9/27/89
1572          */
1573
1574         /*
1575          * process indices
1576          *
1577          * heap_update updates a tuple in the base relation by invalidating it
1578          * and then inserting a new tuple to the relation.      As a side effect,
1579          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1580          * field.  So we now insert index tuples using the new tupleid stored
1581          * there.
1582          */
1583
1584         numIndices = resultRelInfo->ri_NumIndices;
1585         if (numIndices > 0)
1586                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1587
1588         /* AFTER ROW UPDATE Triggers */
1589         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1590 }
1591
1592 static char *
1593 ExecRelCheck(ResultRelInfo *resultRelInfo,
1594                          TupleTableSlot *slot, EState *estate)
1595 {
1596         Relation        rel = resultRelInfo->ri_RelationDesc;
1597         int                     ncheck = rel->rd_att->constr->num_check;
1598         ConstrCheck *check = rel->rd_att->constr->check;
1599         ExprContext *econtext;
1600         MemoryContext oldContext;
1601         List       *qual;
1602         int                     i;
1603
1604         /*
1605          * If first time through for this result relation, build expression
1606          * nodetrees for rel's constraint expressions.  Keep them in the
1607          * per-query memory context so they'll survive throughout the query.
1608          */
1609         if (resultRelInfo->ri_ConstraintExprs == NULL)
1610         {
1611                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1612                 resultRelInfo->ri_ConstraintExprs =
1613                         (List **) palloc(ncheck * sizeof(List *));
1614                 for (i = 0; i < ncheck; i++)
1615                 {
1616                         qual = (List *) stringToNode(check[i].ccbin);
1617                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1618                                 ExecPrepareExpr((Expr *) qual, estate);
1619                 }
1620                 MemoryContextSwitchTo(oldContext);
1621         }
1622
1623         /*
1624          * We will use the EState's per-tuple context for evaluating
1625          * constraint expressions (creating it if it's not already there).
1626          */
1627         econtext = GetPerTupleExprContext(estate);
1628
1629         /* Arrange for econtext's scan tuple to be the tuple under test */
1630         econtext->ecxt_scantuple = slot;
1631
1632         /* And evaluate the constraints */
1633         for (i = 0; i < ncheck; i++)
1634         {
1635                 qual = resultRelInfo->ri_ConstraintExprs[i];
1636
1637                 /*
1638                  * NOTE: SQL92 specifies that a NULL result from a constraint
1639                  * expression is not to be treated as a failure.  Therefore, tell
1640                  * ExecQual to return TRUE for NULL.
1641                  */
1642                 if (!ExecQual(qual, econtext, true))
1643                         return check[i].ccname;
1644         }
1645
1646         /* NULL result means no error */
1647         return (char *) NULL;
1648 }
1649
1650 void
1651 ExecConstraints(const char *caller, ResultRelInfo *resultRelInfo,
1652                                 TupleTableSlot *slot, EState *estate)
1653 {
1654         Relation        rel = resultRelInfo->ri_RelationDesc;
1655         HeapTuple       tuple = slot->val;
1656         TupleConstr *constr = rel->rd_att->constr;
1657
1658         Assert(constr);
1659
1660         if (constr->has_not_null)
1661         {
1662                 int                     natts = rel->rd_att->natts;
1663                 int                     attrChk;
1664
1665                 for (attrChk = 1; attrChk <= natts; attrChk++)
1666                 {
1667                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1668                                 heap_attisnull(tuple, attrChk))
1669                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1670                                          caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1671                 }
1672         }
1673
1674         if (constr->num_check > 0)
1675         {
1676                 char       *failed;
1677
1678                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1679                         elog(ERROR, "%s: rejected due to CHECK constraint \"%s\" on \"%s\"",
1680                                  caller, failed, RelationGetRelationName(rel));
1681         }
1682 }
1683
1684 /*
1685  * Check a modified tuple to see if we want to process its updated version
1686  * under READ COMMITTED rules.
1687  *
1688  * See backend/executor/README for some info about how this works.
1689  */
1690 TupleTableSlot *
1691 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1692 {
1693         evalPlanQual *epq;
1694         EState     *epqstate;
1695         Relation        relation;
1696         HeapTupleData tuple;
1697         HeapTuple       copyTuple = NULL;
1698         bool            endNode;
1699
1700         Assert(rti != 0);
1701
1702         /*
1703          * find relation containing target tuple
1704          */
1705         if (estate->es_result_relation_info != NULL &&
1706                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1707                 relation = estate->es_result_relation_info->ri_RelationDesc;
1708         else
1709         {
1710                 List       *l;
1711
1712                 relation = NULL;
1713                 foreach(l, estate->es_rowMark)
1714                 {
1715                         if (((execRowMark *) lfirst(l))->rti == rti)
1716                         {
1717                                 relation = ((execRowMark *) lfirst(l))->relation;
1718                                 break;
1719                         }
1720                 }
1721                 if (relation == NULL)
1722                         elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1723         }
1724
1725         /*
1726          * fetch tid tuple
1727          *
1728          * Loop here to deal with updated or busy tuples
1729          */
1730         tuple.t_self = *tid;
1731         for (;;)
1732         {
1733                 Buffer          buffer;
1734
1735                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1736                 {
1737                         TransactionId xwait = SnapshotDirty->xmax;
1738
1739                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1740                                 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1741
1742                         /*
1743                          * If tuple is being updated by other transaction then we have
1744                          * to wait for its commit/abort.
1745                          */
1746                         if (TransactionIdIsValid(xwait))
1747                         {
1748                                 ReleaseBuffer(buffer);
1749                                 XactLockTableWait(xwait);
1750                                 continue;
1751                         }
1752
1753                         /*
1754                          * We got tuple - now copy it for use by recheck query.
1755                          */
1756                         copyTuple = heap_copytuple(&tuple);
1757                         ReleaseBuffer(buffer);
1758                         break;
1759                 }
1760
1761                 /*
1762                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1763                  * Note that it's possible to get invalid SnapshotDirty->tid if
1764                  * tuple updated by this transaction. Have we to check this ?
1765                  */
1766                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1767                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1768                 {
1769                         /* updated, so look at the updated copy */
1770                         tuple.t_self = SnapshotDirty->tid;
1771                         continue;
1772                 }
1773
1774                 /*
1775                  * Deleted or updated by this transaction; forget it.
1776                  */
1777                 return NULL;
1778         }
1779
1780         /*
1781          * For UPDATE/DELETE we have to return tid of actual row we're
1782          * executing PQ for.
1783          */
1784         *tid = tuple.t_self;
1785
1786         /*
1787          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1788          */
1789         epq = estate->es_evalPlanQual;
1790         endNode = true;
1791
1792         if (epq != NULL && epq->rti == 0)
1793         {
1794                 /* Top PQ stack entry is idle, so re-use it */
1795                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1796                 epq->rti = rti;
1797                 endNode = false;
1798         }
1799
1800         /*
1801          * If this is request for another RTE - Ra, - then we have to check
1802          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1803          * updated again and we have to re-start old execution for Ra and
1804          * forget all what we done after Ra was suspended. Cool? -:))
1805          */
1806         if (epq != NULL && epq->rti != rti &&
1807                 epq->estate->es_evTuple[rti - 1] != NULL)
1808         {
1809                 do
1810                 {
1811                         evalPlanQual *oldepq;
1812
1813                         /* stop execution */
1814                         EvalPlanQualStop(epq);
1815                         /* pop previous PlanQual from the stack */
1816                         oldepq = epq->next;
1817                         Assert(oldepq && oldepq->rti != 0);
1818                         /* push current PQ to freePQ stack */
1819                         oldepq->free = epq;
1820                         epq = oldepq;
1821                         estate->es_evalPlanQual = epq;
1822                 } while (epq->rti != rti);
1823         }
1824
1825         /*
1826          * If we are requested for another RTE then we have to suspend
1827          * execution of current PlanQual and start execution for new one.
1828          */
1829         if (epq == NULL || epq->rti != rti)
1830         {
1831                 /* try to reuse plan used previously */
1832                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1833
1834                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1835                 {
1836                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1837                         newepq->free = NULL;
1838                         newepq->estate = NULL;
1839                         newepq->planstate = NULL;
1840                 }
1841                 else
1842                 {
1843                         /* recycle previously used PlanQual */
1844                         Assert(newepq->estate == NULL);
1845                         epq->free = NULL;
1846                 }
1847                 /* push current PQ to the stack */
1848                 newepq->next = epq;
1849                 epq = newepq;
1850                 estate->es_evalPlanQual = epq;
1851                 epq->rti = rti;
1852                 endNode = false;
1853         }
1854
1855         Assert(epq->rti == rti);
1856
1857         /*
1858          * Ok - we're requested for the same RTE.  Unfortunately we still have
1859          * to end and restart execution of the plan, because ExecReScan
1860          * wouldn't ensure that upper plan nodes would reset themselves.  We
1861          * could make that work if insertion of the target tuple were
1862          * integrated with the Param mechanism somehow, so that the upper plan
1863          * nodes know that their children's outputs have changed.
1864          *
1865          * Note that the stack of free evalPlanQual nodes is quite useless at
1866          * the moment, since it only saves us from pallocing/releasing the
1867          * evalPlanQual nodes themselves.  But it will be useful once we
1868          * implement ReScan instead of end/restart for re-using PlanQual nodes.
1869          */
1870         if (endNode)
1871         {
1872                 /* stop execution */
1873                 EvalPlanQualStop(epq);
1874         }
1875
1876         /*
1877          * Initialize new recheck query.
1878          *
1879          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need
1880          * to instead copy down changeable state from the top plan (including
1881          * es_result_relation_info, es_junkFilter) and reset locally changeable
1882          * state in the epq (including es_param_exec_vals, es_evTupleNull).
1883          */
1884         EvalPlanQualStart(epq, estate, epq->next);
1885
1886         /*
1887          * free old RTE' tuple, if any, and store target tuple where
1888          * relation's scan node will see it
1889          */
1890         epqstate = epq->estate;
1891         if (epqstate->es_evTuple[rti - 1] != NULL)
1892                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1893         epqstate->es_evTuple[rti - 1] = copyTuple;
1894
1895         return EvalPlanQualNext(estate);
1896 }
1897
1898 static TupleTableSlot *
1899 EvalPlanQualNext(EState *estate)
1900 {
1901         evalPlanQual *epq = estate->es_evalPlanQual;
1902         MemoryContext oldcontext;
1903         TupleTableSlot *slot;
1904
1905         Assert(epq->rti != 0);
1906
1907 lpqnext:;
1908         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1909         slot = ExecProcNode(epq->planstate);
1910         MemoryContextSwitchTo(oldcontext);
1911
1912         /*
1913          * No more tuples for this PQ. Continue previous one.
1914          */
1915         if (TupIsNull(slot))
1916         {
1917                 evalPlanQual *oldepq;
1918
1919                 /* stop execution */
1920                 EvalPlanQualStop(epq);
1921                 /* pop old PQ from the stack */
1922                 oldepq = epq->next;
1923                 if (oldepq == NULL)
1924                 {
1925                         /* this is the first (oldest) PQ - mark as free */
1926                         epq->rti = 0;
1927                         estate->es_useEvalPlan = false;
1928                         /* and continue Query execution */
1929                         return (NULL);
1930                 }
1931                 Assert(oldepq->rti != 0);
1932                 /* push current PQ to freePQ stack */
1933                 oldepq->free = epq;
1934                 epq = oldepq;
1935                 estate->es_evalPlanQual = epq;
1936                 goto lpqnext;
1937         }
1938
1939         return (slot);
1940 }
1941
1942 static void
1943 EndEvalPlanQual(EState *estate)
1944 {
1945         evalPlanQual *epq = estate->es_evalPlanQual;
1946
1947         if (epq->rti == 0)                      /* plans already shutdowned */
1948         {
1949                 Assert(epq->next == NULL);
1950                 return;
1951         }
1952
1953         for (;;)
1954         {
1955                 evalPlanQual *oldepq;
1956
1957                 /* stop execution */
1958                 EvalPlanQualStop(epq);
1959                 /* pop old PQ from the stack */
1960                 oldepq = epq->next;
1961                 if (oldepq == NULL)
1962                 {
1963                         /* this is the first (oldest) PQ - mark as free */
1964                         epq->rti = 0;
1965                         estate->es_useEvalPlan = false;
1966                         break;
1967                 }
1968                 Assert(oldepq->rti != 0);
1969                 /* push current PQ to freePQ stack */
1970                 oldepq->free = epq;
1971                 epq = oldepq;
1972                 estate->es_evalPlanQual = epq;
1973         }
1974 }
1975
1976 /*
1977  * Start execution of one level of PlanQual.
1978  *
1979  * This is a cut-down version of ExecutorStart(): we copy some state from
1980  * the top-level estate rather than initializing it fresh.
1981  */
1982 static void
1983 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
1984 {
1985         EState     *epqstate;
1986         int                     rtsize;
1987         MemoryContext oldcontext;
1988
1989         rtsize = length(estate->es_range_table);
1990
1991         epq->estate = epqstate = CreateExecutorState();
1992
1993         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
1994
1995         /*
1996          * The epqstates share the top query's copy of unchanging state such
1997          * as the snapshot, rangetable, result-rel info, and external Param info.
1998          * They need their own copies of local state, including a tuple table,
1999          * es_param_exec_vals, etc.
2000          */
2001         epqstate->es_direction = ForwardScanDirection;
2002         epqstate->es_snapshot = estate->es_snapshot;
2003         epqstate->es_range_table = estate->es_range_table;
2004         epqstate->es_result_relations = estate->es_result_relations;
2005         epqstate->es_num_result_relations = estate->es_num_result_relations;
2006         epqstate->es_result_relation_info = estate->es_result_relation_info;
2007         epqstate->es_junkFilter = estate->es_junkFilter;
2008         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
2009         epqstate->es_param_list_info = estate->es_param_list_info;
2010         if (estate->es_topPlan->nParamExec > 0)
2011                 epqstate->es_param_exec_vals = (ParamExecData *)
2012                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
2013         epqstate->es_rowMark = estate->es_rowMark;
2014         epqstate->es_instrument = estate->es_instrument;
2015         epqstate->es_force_oids = estate->es_force_oids;
2016         epqstate->es_topPlan = estate->es_topPlan;
2017         /*
2018          * Each epqstate must have its own es_evTupleNull state, but
2019          * all the stack entries share es_evTuple state.  This allows
2020          * sub-rechecks to inherit the value being examined by an
2021          * outer recheck.
2022          */
2023         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
2024         if (priorepq == NULL)
2025                 /* first PQ stack entry */
2026                 epqstate->es_evTuple = (HeapTuple *)
2027                         palloc0(rtsize * sizeof(HeapTuple));
2028         else
2029                 /* later stack entries share the same storage */
2030                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
2031
2032         epqstate->es_tupleTable =
2033                 ExecCreateTupleTable(estate->es_tupleTable->size);
2034
2035         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
2036
2037         MemoryContextSwitchTo(oldcontext);
2038 }
2039
2040 /*
2041  * End execution of one level of PlanQual.
2042  *
2043  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2044  * of the normal cleanup, but *not* close result relations (which we are
2045  * just sharing from the outer query).
2046  */
2047 static void
2048 EvalPlanQualStop(evalPlanQual *epq)
2049 {
2050         EState     *epqstate = epq->estate;
2051         MemoryContext oldcontext;
2052
2053         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2054
2055         ExecEndNode(epq->planstate);
2056
2057         ExecDropTupleTable(epqstate->es_tupleTable, true);
2058         epqstate->es_tupleTable = NULL;
2059
2060         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2061         {
2062                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2063                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2064         }
2065
2066         MemoryContextSwitchTo(oldcontext);
2067
2068         FreeExecutorState(epqstate);
2069
2070         epq->estate = NULL;
2071         epq->planstate = NULL;
2072 }