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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 1.190 2002/12/05 15:50:30 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 /* decls for local routines only used within this module */
  50 static void InitPlan(QueryDesc *queryDesc);
  51 static void initResultRelInfo(ResultRelInfo *resultRelInfo,
  52                                   Index resultRelationIndex,
  53                                   List *rangeTable,
  54                                   CmdType operation);
  55 static void EndPlan(PlanState *planstate, EState *estate);
  56 static TupleTableSlot *ExecutePlan(EState *estate, PlanState *planstate,
  57                         CmdType operation,
  58                         long numberTuples,
  59                         ScanDirection direction,
  60                         DestReceiver *destfunc);
  61 static void ExecSelect(TupleTableSlot *slot,
  62                    DestReceiver *destfunc,
  63                    EState *estate);
  64 static void ExecInsert(TupleTableSlot *slot, ItemPointer tupleid,
  65                    EState *estate);
  66 static void ExecDelete(TupleTableSlot *slot, ItemPointer tupleid,
  67                    EState *estate);
  68 static void ExecUpdate(TupleTableSlot *slot, ItemPointer tupleid,
  69                    EState *estate);
  70 static TupleTableSlot *EvalPlanQualNext(EState *estate);
  71 static void EndEvalPlanQual(EState *estate);
  72 static void ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation);
  73
  74 /* end of local decls */
  75
  76
  77 /* ----------------------------------------------------------------
  78  *              ExecutorStart
  79  *
  80  *              This routine must be called at the beginning of any execution of any
  81  *              query plan
  82  *
  83  * Takes a QueryDesc previously created by CreateQueryDesc (it's not real
  84  * clear why we bother to separate the two functions, but...).  The tupDesc
  85  * field of the QueryDesc is filled in to describe the tuples that will be
  86  * returned, and the internal fields (estate and planstate) are set up.
  87  *
  88  * XXX this will change soon:
  89  * NB: the CurrentMemoryContext when this is called must be the context
  90  * to be used as the per-query context for the query plan.      ExecutorRun()
  91  * and ExecutorEnd() must be called in this same memory context.
  92  * ----------------------------------------------------------------
  93  */
  94 void
  95 ExecutorStart(QueryDesc *queryDesc)
  96 {
  97         EState     *estate;
  98
  99         /* sanity checks: queryDesc must not be started already */
 100         Assert(queryDesc != NULL);
 101         Assert(queryDesc->estate == NULL);
 102
 103         /*
 104          * Build EState, fill with parameters from queryDesc
 105          */
 106         estate = CreateExecutorState();
 107         queryDesc->estate = estate;
 108
 109         estate->es_param_list_info = queryDesc->params;
 110
 111         if (queryDesc->plantree->nParamExec > 0)
 112                 estate->es_param_exec_vals = (ParamExecData *)
 113                         palloc0(queryDesc->plantree->nParamExec * sizeof(ParamExecData));
 114
 115         estate->es_instrument = queryDesc->doInstrument;
 116
 117         /*
 118          * Make our own private copy of the current query snapshot data.
 119          *
 120          * This "freezes" our idea of which tuples are good and which are not for
 121          * the life of this query, even if it outlives the current command and
 122          * current snapshot.
 123          */
 124         estate->es_snapshot = CopyQuerySnapshot();
 125
 126         /*
 127          * Initialize the plan state tree
 128          */
 129         InitPlan(queryDesc);
 130 }
 131
 132 /* ----------------------------------------------------------------
 133  *              ExecutorRun
 134  *
 135  *              This is the main routine of the executor module. It accepts
 136  *              the query descriptor from the traffic cop and executes the
 137  *              query plan.
 138  *
 139  *              ExecutorStart must have been called already.
 140  *
 141  *              If direction is NoMovementScanDirection then nothing is done
 142  *              except to start up/shut down the destination.  Otherwise,
 143  *              we retrieve up to 'count' tuples in the specified direction.
 144  *
 145  *              Note: count = 0 is interpreted as no portal limit, e.g. run to
 146  *              completion.
 147  *
 148  * ----------------------------------------------------------------
 149  */
 150 TupleTableSlot *
 151 ExecutorRun(QueryDesc *queryDesc,
 152                         ScanDirection direction, long count)
 153 {
 154         CmdType         operation;
 155         EState     *estate;
 156         CommandDest dest;
 157         DestReceiver *destfunc;
 158         TupleTableSlot *result;
 159
 160         /*
 161          * sanity checks
 162          */
 163         Assert(queryDesc != NULL);
 164
 165         /*
 166          * extract information from the query descriptor and the query
 167          * feature.
 168          */
 169         operation = queryDesc->operation;
 170         estate = queryDesc->estate;
 171         dest = queryDesc->dest;
 172
 173         /*
 174          * startup tuple receiver
 175          */
 176         estate->es_processed = 0;
 177         estate->es_lastoid = InvalidOid;
 178
 179         destfunc = DestToFunction(dest);
 180         (*destfunc->setup) (destfunc, (int) operation,
 181                                                 queryDesc->portalName, queryDesc->tupDesc);
 182
 183         /*
 184          * run plan
 185          */
 186         if (direction == NoMovementScanDirection)
 187                 result = NULL;
 188         else
 189                 result = ExecutePlan(estate,
 190                                                          queryDesc->planstate,
 191                                                          operation,
 192                                                          count,
 193                                                          direction,
 194                                                          destfunc);
 195
 196         /*
 197          * shutdown receiver
 198          */
 199         (*destfunc->cleanup) (destfunc);
 200
 201         return result;
 202 }
 203
 204 /* ----------------------------------------------------------------
 205  *              ExecutorEnd
 206  *
 207  *              This routine must be called at the end of execution of any
 208  *              query plan
 209  * ----------------------------------------------------------------
 210  */
 211 void
 212 ExecutorEnd(QueryDesc *queryDesc)
 213 {
 214         EState     *estate;
 215
 216         /* sanity checks */
 217         Assert(queryDesc != NULL);
 218
 219         estate = queryDesc->estate;
 220
 221         EndPlan(queryDesc->planstate, estate);
 222
 223         if (estate->es_snapshot != NULL)
 224         {
 225                 if (estate->es_snapshot->xcnt > 0)
 226                         pfree(estate->es_snapshot->xip);
 227                 pfree(estate->es_snapshot);
 228                 estate->es_snapshot = NULL;
 229         }
 230
 231         if (estate->es_param_exec_vals != NULL)
 232         {
 233                 pfree(estate->es_param_exec_vals);
 234                 estate->es_param_exec_vals = NULL;
 235         }
 236 }
 237
 238
 239 /*
 240  * CreateExecutorState
 241  */
 242 EState *
 243 CreateExecutorState(void)
 244 {
 245         EState     *state;
 246
 247         /*
 248          * create a new executor state
 249          */
 250         state = makeNode(EState);
 251
 252         /*
 253          * initialize the Executor State structure
 254          */
 255         state->es_direction = ForwardScanDirection;
 256         state->es_range_table = NIL;
 257
 258         state->es_result_relations = NULL;
 259         state->es_num_result_relations = 0;
 260         state->es_result_relation_info = NULL;
 261
 262         state->es_junkFilter = NULL;
 263
 264         state->es_into_relation_descriptor = NULL;
 265
 266         state->es_param_list_info = NULL;
 267         state->es_param_exec_vals = NULL;
 268
 269         state->es_tupleTable = NULL;
 270
 271         state->es_query_cxt = CurrentMemoryContext;
 272
 273         state->es_instrument = false;
 274
 275         state->es_per_tuple_exprcontext = NULL;
 276
 277         /*
 278          * return the executor state structure
 279          */
 280         return state;
 281 }
 282
 283
 284 /*
 285  * ExecCheckRTPerms
 286  *              Check access permissions for all relations listed in a range table.
 287  */
 288 void
 289 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 290 {
 291         List       *lp;
 292
 293         foreach(lp, rangeTable)
 294         {
 295                 RangeTblEntry *rte = lfirst(lp);
 296
 297                 ExecCheckRTEPerms(rte, operation);
 298         }
 299 }
 300
 301 /*
 302  * ExecCheckRTEPerms
 303  *              Check access permissions for a single RTE.
 304  */
 305 static void
 306 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 307 {
 308         Oid                     relOid;
 309         AclId           userid;
 310         AclResult       aclcheck_result;
 311
 312         /*
 313          * If it's a subquery, recursively examine its rangetable.
 314          */
 315         if (rte->rtekind == RTE_SUBQUERY)
 316         {
 317                 ExecCheckRTPerms(rte->subquery->rtable, operation);
 318                 return;
 319         }
 320
 321         /*
 322          * Otherwise, only plain-relation RTEs need to be checked here.
 323          * Function RTEs are checked by init_fcache when the function is prepared
 324          * for execution. Join and special RTEs need no checks.
 325          */
 326         if (rte->rtekind != RTE_RELATION)
 327                 return;
 328
 329         relOid = rte->relid;
 330
 331         /*
 332          * userid to check as: current user unless we have a setuid
 333          * indication.
 334          *
 335          * Note: GetUserId() is presently fast enough that there's no harm in
 336          * calling it separately for each RTE.  If that stops being true, we
 337          * could call it once in ExecCheckRTPerms and pass the userid down
 338          * from there.  But for now, no need for the extra clutter.
 339          */
 340         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 341
 342 #define CHECK(MODE)             pg_class_aclcheck(relOid, userid, MODE)
 343
 344         if (rte->checkForRead)
 345         {
 346                 aclcheck_result = CHECK(ACL_SELECT);
 347                 if (aclcheck_result != ACLCHECK_OK)
 348                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 349         }
 350
 351         if (rte->checkForWrite)
 352         {
 353                 /*
 354                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 355                  * Right now we don't distinguish that from true update as far as
 356                  * permissions checks are concerned.
 357                  */
 358                 switch (operation)
 359                 {
 360                         case CMD_INSERT:
 361                                 aclcheck_result = CHECK(ACL_INSERT);
 362                                 break;
 363                         case CMD_SELECT:
 364                         case CMD_UPDATE:
 365                                 aclcheck_result = CHECK(ACL_UPDATE);
 366                                 break;
 367                         case CMD_DELETE:
 368                                 aclcheck_result = CHECK(ACL_DELETE);
 369                                 break;
 370                         default:
 371                                 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
 372                                          operation);
 373                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 374                                 break;
 375                 }
 376                 if (aclcheck_result != ACLCHECK_OK)
 377                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 378         }
 379 }
 380
 381
 382 /* ===============================================================
 383  * ===============================================================
 384                                                  static routines follow
 385  * ===============================================================
 386  * ===============================================================
 387  */
 388
 389 typedef struct execRowMark
 390 {
 391         Relation        relation;
 392         Index           rti;
 393         char            resname[32];
 394 } execRowMark;
 395
 396 typedef struct evalPlanQual
 397 {
 398         Plan       *plan;                       /* XXX temporary */
 399         PlanState  *planstate;
 400         Index           rti;
 401         EState          estate;
 402         struct evalPlanQual *free;
 403 } evalPlanQual;
 404
 405 /* ----------------------------------------------------------------
 406  *              InitPlan
 407  *
 408  *              Initializes the query plan: open files, allocate storage
 409  *              and start up the rule manager
 410  * ----------------------------------------------------------------
 411  */
 412 static void
 413 InitPlan(QueryDesc *queryDesc)
 414 {
 415         CmdType         operation = queryDesc->operation;
 416         Query *parseTree = queryDesc->parsetree;
 417         Plan *plan = queryDesc->plantree;
 418         EState *estate = queryDesc->estate;
 419         PlanState  *planstate;
 420         List       *rangeTable;
 421         Relation        intoRelationDesc;
 422         TupleDesc       tupType;
 423
 424         /*
 425          * Do permissions checks.  It's sufficient to examine the query's
 426          * top rangetable here --- subplan RTEs will be checked during
 427          * ExecInitSubPlan().
 428          */
 429         ExecCheckRTPerms(parseTree->rtable, operation);
 430
 431         /*
 432          * get information from query descriptor
 433          */
 434         rangeTable = parseTree->rtable;
 435
 436         /*
 437          * initialize the node's execution state
 438          */
 439         estate->es_range_table = rangeTable;
 440
 441         /*
 442          * if there is a result relation, initialize result relation stuff
 443          */
 444         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 445         {
 446                 List       *resultRelations = parseTree->resultRelations;
 447                 int                     numResultRelations;
 448                 ResultRelInfo *resultRelInfos;
 449
 450                 if (resultRelations != NIL)
 451                 {
 452                         /*
 453                          * Multiple result relations (due to inheritance)
 454                          * parseTree->resultRelations identifies them all
 455                          */
 456                         ResultRelInfo *resultRelInfo;
 457
 458                         numResultRelations = length(resultRelations);
 459                         resultRelInfos = (ResultRelInfo *)
 460                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 461                         resultRelInfo = resultRelInfos;
 462                         while (resultRelations != NIL)
 463                         {
 464                                 initResultRelInfo(resultRelInfo,
 465                                                                   lfirsti(resultRelations),
 466                                                                   rangeTable,
 467                                                                   operation);
 468                                 resultRelInfo++;
 469                                 resultRelations = lnext(resultRelations);
 470                         }
 471                 }
 472                 else
 473                 {
 474                         /*
 475                          * Single result relation identified by
 476                          * parseTree->resultRelation
 477                          */
 478                         numResultRelations = 1;
 479                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 480                         initResultRelInfo(resultRelInfos,
 481                                                           parseTree->resultRelation,
 482                                                           rangeTable,
 483                                                           operation);
 484                 }
 485
 486                 estate->es_result_relations = resultRelInfos;
 487                 estate->es_num_result_relations = numResultRelations;
 488                 /* Initialize to first or only result rel */
 489                 estate->es_result_relation_info = resultRelInfos;
 490         }
 491         else
 492         {
 493                 /*
 494                  * if no result relation, then set state appropriately
 495                  */
 496                 estate->es_result_relations = NULL;
 497                 estate->es_num_result_relations = 0;
 498                 estate->es_result_relation_info = NULL;
 499         }
 500
 501         /*
 502          * Have to lock relations selected for update
 503          */
 504         estate->es_rowMark = NIL;
 505         if (parseTree->rowMarks != NIL)
 506         {
 507                 List       *l;
 508
 509                 foreach(l, parseTree->rowMarks)
 510                 {
 511                         Index           rti = lfirsti(l);
 512                         Oid                     relid = getrelid(rti, rangeTable);
 513                         Relation        relation;
 514                         execRowMark *erm;
 515
 516                         relation = heap_open(relid, RowShareLock);
 517                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 518                         erm->relation = relation;
 519                         erm->rti = rti;
 520                         snprintf(erm->resname, 32, "ctid%u", rti);
 521                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 522                 }
 523         }
 524
 525         /*
 526          * initialize the executor "tuple" table.  We need slots for all the
 527          * plan nodes, plus possibly output slots for the junkfilter(s). At
 528          * this point we aren't sure if we need junkfilters, so just add slots
 529          * for them unconditionally.
 530          */
 531         {
 532                 int                     nSlots = ExecCountSlotsNode(plan);
 533
 534                 if (parseTree->resultRelations != NIL)
 535                         nSlots += length(parseTree->resultRelations);
 536                 else
 537                         nSlots += 1;
 538                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 539         }
 540
 541         /* mark EvalPlanQual not active */
 542         estate->es_origPlan = plan;
 543         estate->es_evalPlanQual = NULL;
 544         estate->es_evTuple = NULL;
 545         estate->es_evTupleNull = NULL;
 546         estate->es_useEvalPlan = false;
 547
 548         /*
 549          * initialize the private state information for all the nodes in the
 550          * query tree.  This opens files, allocates storage and leaves us
 551          * ready to start processing tuples.
 552          */
 553         planstate = ExecInitNode(plan, estate);
 554
 555         /*
 556          * Get the tuple descriptor describing the type of tuples to return.
 557          * (this is especially important if we are creating a relation with
 558          * "SELECT INTO")
 559          */
 560         tupType = ExecGetTupType(planstate);
 561
 562         /*
 563          * Initialize the junk filter if needed. SELECT and INSERT queries
 564          * need a filter if there are any junk attrs in the tlist.      UPDATE and
 565          * DELETE always need one, since there's always a junk 'ctid'
 566          * attribute present --- no need to look first.
 567          */
 568         {
 569                 bool            junk_filter_needed = false;
 570                 List       *tlist;
 571
 572                 switch (operation)
 573                 {
 574                         case CMD_SELECT:
 575                         case CMD_INSERT:
 576                                 foreach(tlist, plan->targetlist)
 577                                 {
 578                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 579
 580                                         if (tle->resdom->resjunk)
 581                                         {
 582                                                 junk_filter_needed = true;
 583                                                 break;
 584                                         }
 585                                 }
 586                                 break;
 587                         case CMD_UPDATE:
 588                         case CMD_DELETE:
 589                                 junk_filter_needed = true;
 590                                 break;
 591                         default:
 592                                 break;
 593                 }
 594
 595                 if (junk_filter_needed)
 596                 {
 597                         /*
 598                          * If there are multiple result relations, each one needs its
 599                          * own junk filter.  Note this is only possible for
 600                          * UPDATE/DELETE, so we can't be fooled by some needing a
 601                          * filter and some not.
 602                          */
 603                         if (parseTree->resultRelations != NIL)
 604                         {
 605                                 PlanState **appendplans;
 606                                 int                     as_nplans;
 607                                 ResultRelInfo *resultRelInfo;
 608                                 int                     i;
 609
 610                                 /* Top plan had better be an Append here. */
 611                                 Assert(IsA(plan, Append));
 612                                 Assert(((Append *) plan)->isTarget);
 613                                 Assert(IsA(planstate, AppendState));
 614                                 appendplans = ((AppendState *) planstate)->appendplans;
 615                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 616                                 Assert(as_nplans == estate->es_num_result_relations);
 617                                 resultRelInfo = estate->es_result_relations;
 618                                 for (i = 0; i < as_nplans; i++)
 619                                 {
 620                                         PlanState  *subplan = appendplans[i];
 621                                         JunkFilter *j;
 622
 623                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 624                                                                                    ExecGetTupType(subplan),
 625                                                           ExecAllocTableSlot(estate->es_tupleTable));
 626                                         resultRelInfo->ri_junkFilter = j;
 627                                         resultRelInfo++;
 628                                 }
 629
 630                                 /*
 631                                  * Set active junkfilter too; at this point ExecInitAppend
 632                                  * has already selected an active result relation...
 633                                  */
 634                                 estate->es_junkFilter =
 635                                         estate->es_result_relation_info->ri_junkFilter;
 636                         }
 637                         else
 638                         {
 639                                 /* Normal case with just one JunkFilter */
 640                                 JunkFilter *j;
 641
 642                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 643                                                                            tupType,
 644                                                           ExecAllocTableSlot(estate->es_tupleTable));
 645                                 estate->es_junkFilter = j;
 646                                 if (estate->es_result_relation_info)
 647                                         estate->es_result_relation_info->ri_junkFilter = j;
 648
 649                                 /* For SELECT, want to return the cleaned tuple type */
 650                                 if (operation == CMD_SELECT)
 651                                         tupType = j->jf_cleanTupType;
 652                         }
 653                 }
 654                 else
 655                         estate->es_junkFilter = NULL;
 656         }
 657
 658         /*
 659          * initialize the "into" relation
 660          */
 661         intoRelationDesc = (Relation) NULL;
 662
 663         if (operation == CMD_SELECT)
 664         {
 665                 if (!parseTree->isPortal)
 666                 {
 667                         /*
 668                          * a select into table --- need to create the "into" table
 669                          */
 670                         if (parseTree->into != NULL)
 671                         {
 672                                 char       *intoName;
 673                                 Oid                     namespaceId;
 674                                 AclResult       aclresult;
 675                                 Oid                     intoRelationId;
 676                                 TupleDesc       tupdesc;
 677
 678                                 /*
 679                                  * find namespace to create in, check permissions
 680                                  */
 681                                 intoName = parseTree->into->relname;
 682                                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 683
 684                                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 685                                                                                                   ACL_CREATE);
 686                                 if (aclresult != ACLCHECK_OK)
 687                                         aclcheck_error(aclresult,
 688                                                                    get_namespace_name(namespaceId));
 689
 690                                 /*
 691                                  * have to copy tupType to get rid of constraints
 692                                  */
 693                                 tupdesc = CreateTupleDescCopy(tupType);
 694
 695                                 /*
 696                                  * Formerly we forced the output table to have OIDs, but
 697                                  * as of 7.3 it will not have OIDs, because it's too late
 698                                  * here to change the tupdescs of the already-initialized
 699                                  * plan tree.  (Perhaps we could recurse and change them
 700                                  * all, but it's not really worth the trouble IMHO...)
 701                                  */
 702
 703                                 intoRelationId =
 704                                         heap_create_with_catalog(intoName,
 705                                                                                          namespaceId,
 706                                                                                          tupdesc,
 707                                                                                          RELKIND_RELATION,
 708                                                                                          false,
 709                                                                                          ONCOMMIT_NOOP,
 710                                                                                          allowSystemTableMods);
 711
 712                                 FreeTupleDesc(tupdesc);
 713
 714                                 /*
 715                                  * Advance command counter so that the newly-created
 716                                  * relation's catalog tuples will be visible to heap_open.
 717                                  */
 718                                 CommandCounterIncrement();
 719
 720                                 /*
 721                                  * If necessary, create a TOAST table for the into
 722                                  * relation. Note that AlterTableCreateToastTable ends
 723                                  * with CommandCounterIncrement(), so that the TOAST table
 724                                  * will be visible for insertion.
 725                                  */
 726                                 AlterTableCreateToastTable(intoRelationId, true);
 727
 728                                 intoRelationDesc = heap_open(intoRelationId,
 729                                                                                          AccessExclusiveLock);
 730                         }
 731                 }
 732         }
 733
 734         estate->es_into_relation_descriptor = intoRelationDesc;
 735
 736         queryDesc->tupDesc = tupType;
 737         queryDesc->planstate = planstate;
 738 }
 739
 740 /*
 741  * Initialize ResultRelInfo data for one result relation
 742  */
 743 static void
 744 initResultRelInfo(ResultRelInfo *resultRelInfo,
 745                                   Index resultRelationIndex,
 746                                   List *rangeTable,
 747                                   CmdType operation)
 748 {
 749         Oid                     resultRelationOid;
 750         Relation        resultRelationDesc;
 751
 752         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 753         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 754
 755         switch (resultRelationDesc->rd_rel->relkind)
 756         {
 757                 case RELKIND_SEQUENCE:
 758                         elog(ERROR, "You can't change sequence relation %s",
 759                                  RelationGetRelationName(resultRelationDesc));
 760                         break;
 761                 case RELKIND_TOASTVALUE:
 762                         elog(ERROR, "You can't change toast relation %s",
 763                                  RelationGetRelationName(resultRelationDesc));
 764                         break;
 765                 case RELKIND_VIEW:
 766                         elog(ERROR, "You can't change view relation %s",
 767                                  RelationGetRelationName(resultRelationDesc));
 768                         break;
 769         }
 770
 771         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 772         resultRelInfo->type = T_ResultRelInfo;
 773         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 774         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 775         resultRelInfo->ri_NumIndices = 0;
 776         resultRelInfo->ri_IndexRelationDescs = NULL;
 777         resultRelInfo->ri_IndexRelationInfo = NULL;
 778         /* make a copy so as not to depend on relcache info not changing... */
 779         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 780         resultRelInfo->ri_TrigFunctions = NULL;
 781         resultRelInfo->ri_ConstraintExprs = NULL;
 782         resultRelInfo->ri_junkFilter = NULL;
 783
 784         /*
 785          * If there are indices on the result relation, open them and save
 786          * descriptors in the result relation info, so that we can add new
 787          * index entries for the tuples we add/update.  We need not do this
 788          * for a DELETE, however, since deletion doesn't affect indexes.
 789          */
 790         if (resultRelationDesc->rd_rel->relhasindex &&
 791                 operation != CMD_DELETE)
 792                 ExecOpenIndices(resultRelInfo);
 793 }
 794
 795 /* ----------------------------------------------------------------
 796  *              EndPlan
 797  *
 798  *              Cleans up the query plan -- closes files and frees up storage
 799  * ----------------------------------------------------------------
 800  */
 801 static void
 802 EndPlan(PlanState *planstate, EState *estate)
 803 {
 804         ResultRelInfo *resultRelInfo;
 805         int                     i;
 806         List       *l;
 807
 808         /*
 809          * shut down any PlanQual processing we were doing
 810          */
 811         if (estate->es_evalPlanQual != NULL)
 812                 EndEvalPlanQual(estate);
 813
 814         /*
 815          * shut down the node-type-specific query processing
 816          */
 817         ExecEndNode(planstate);
 818
 819         /*
 820          * destroy the executor "tuple" table.
 821          */
 822         ExecDropTupleTable(estate->es_tupleTable, true);
 823         estate->es_tupleTable = NULL;
 824
 825         /*
 826          * close the result relation(s) if any, but hold locks until xact
 827          * commit.      Also clean up junkfilters if present.
 828          */
 829         resultRelInfo = estate->es_result_relations;
 830         for (i = estate->es_num_result_relations; i > 0; i--)
 831         {
 832                 /* Close indices and then the relation itself */
 833                 ExecCloseIndices(resultRelInfo);
 834                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 835                 /* Delete the junkfilter if any */
 836                 if (resultRelInfo->ri_junkFilter != NULL)
 837                         ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
 838                 resultRelInfo++;
 839         }
 840
 841         /*
 842          * close the "into" relation if necessary, again keeping lock
 843          */
 844         if (estate->es_into_relation_descriptor != NULL)
 845                 heap_close(estate->es_into_relation_descriptor, NoLock);
 846
 847         /*
 848          * There might be a junkfilter without a result relation.
 849          */
 850         if (estate->es_num_result_relations == 0 &&
 851                 estate->es_junkFilter != NULL)
 852         {
 853                 ExecFreeJunkFilter(estate->es_junkFilter);
 854                 estate->es_junkFilter = NULL;
 855         }
 856
 857         /*
 858          * close any relations selected FOR UPDATE, again keeping locks
 859          */
 860         foreach(l, estate->es_rowMark)
 861         {
 862                 execRowMark *erm = lfirst(l);
 863
 864                 heap_close(erm->relation, NoLock);
 865         }
 866 }
 867
 868 /* ----------------------------------------------------------------
 869  *              ExecutePlan
 870  *
 871  *              processes the query plan to retrieve 'numberTuples' tuples in the
 872  *              direction specified.
 873  *              Retrieves all tuples if numberTuples is 0
 874  *
 875  *              result is either a slot containing the last tuple in the case
 876  *              of a SELECT or NULL otherwise.
 877  *
 878  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 879  * user can see it
 880  * ----------------------------------------------------------------
 881  */
 882 static TupleTableSlot *
 883 ExecutePlan(EState *estate,
 884                         PlanState *planstate,
 885                         CmdType operation,
 886                         long numberTuples,
 887                         ScanDirection direction,
 888                         DestReceiver *destfunc)
 889 {
 890         JunkFilter                      *junkfilter;
 891         TupleTableSlot          *slot;
 892         ItemPointer                      tupleid = NULL;
 893         ItemPointerData          tuple_ctid;
 894         long                             current_tuple_count;
 895         TupleTableSlot          *result;
 896
 897         /*
 898          * initialize local variables
 899          */
 900         slot = NULL;
 901         current_tuple_count = 0;
 902         result = NULL;
 903
 904         /*
 905          * Set the direction.
 906          */
 907         estate->es_direction = direction;
 908
 909         /*
 910          * Process BEFORE EACH STATEMENT triggers
 911          */
 912         switch (operation)
 913         {
 914                 case CMD_UPDATE:
 915                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
 916                         break;
 917                 case CMD_DELETE:
 918                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
 919                         break;
 920                 case CMD_INSERT:
 921                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
 922                         break;
 923                 default:
 924                         /* do nothing */
 925                         break;
 926         }
 927
 928         /*
 929          * Loop until we've processed the proper number of tuples from the
 930          * plan.
 931          */
 932
 933         for (;;)
 934         {
 935                 /* Reset the per-output-tuple exprcontext */
 936                 ResetPerTupleExprContext(estate);
 937
 938                 /*
 939                  * Execute the plan and obtain a tuple
 940                  */
 941 lnext:  ;
 942                 if (estate->es_useEvalPlan)
 943                 {
 944                         slot = EvalPlanQualNext(estate);
 945                         if (TupIsNull(slot))
 946                                 slot = ExecProcNode(planstate);
 947                 }
 948                 else
 949                         slot = ExecProcNode(planstate);
 950
 951                 /*
 952                  * if the tuple is null, then we assume there is nothing more to
 953                  * process so we just return null...
 954                  */
 955                 if (TupIsNull(slot))
 956                 {
 957                         result = NULL;
 958                         break;
 959                 }
 960
 961                 /*
 962                  * if we have a junk filter, then project a new tuple with the
 963                  * junk removed.
 964                  *
 965                  * Store this new "clean" tuple in the junkfilter's resultSlot.
 966                  * (Formerly, we stored it back over the "dirty" tuple, which is
 967                  * WRONG because that tuple slot has the wrong descriptor.)
 968                  *
 969                  * Also, extract all the junk information we need.
 970                  */
 971                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
 972                 {
 973                         Datum           datum;
 974                         HeapTuple       newTuple;
 975                         bool            isNull;
 976
 977                         /*
 978                          * extract the 'ctid' junk attribute.
 979                          */
 980                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
 981                         {
 982                                 if (!ExecGetJunkAttribute(junkfilter,
 983                                                                                   slot,
 984                                                                                   "ctid",
 985                                                                                   &datum,
 986                                                                                   &isNull))
 987                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
 988
 989                                 /* shouldn't ever get a null result... */
 990                                 if (isNull)
 991                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
 992
 993                                 tupleid = (ItemPointer) DatumGetPointer(datum);
 994                                 tuple_ctid = *tupleid;  /* make sure we don't free the
 995                                                                                  * ctid!! */
 996                                 tupleid = &tuple_ctid;
 997                         }
 998                         else if (estate->es_rowMark != NIL)
 999                         {
1000                                 List       *l;
1001
1002                 lmark:  ;
1003                                 foreach(l, estate->es_rowMark)
1004                                 {
1005                                         execRowMark *erm = lfirst(l);
1006                                         Buffer          buffer;
1007                                         HeapTupleData tuple;
1008                                         TupleTableSlot *newSlot;
1009                                         int                     test;
1010
1011                                         if (!ExecGetJunkAttribute(junkfilter,
1012                                                                                           slot,
1013                                                                                           erm->resname,
1014                                                                                           &datum,
1015                                                                                           &isNull))
1016                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1017                                                          erm->resname);
1018
1019                                         /* shouldn't ever get a null result... */
1020                                         if (isNull)
1021                                                 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1022                                                          erm->resname);
1023
1024                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1025                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1026                                                                                         estate->es_snapshot->curcid);
1027                                         ReleaseBuffer(buffer);
1028                                         switch (test)
1029                                         {
1030                                                 case HeapTupleSelfUpdated:
1031                                                         /* treat it as deleted; do not process */
1032                                                         goto lnext;
1033
1034                                                 case HeapTupleMayBeUpdated:
1035                                                         break;
1036
1037                                                 case HeapTupleUpdated:
1038                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1039                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1040                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1041                                                                   (ItemPointer) DatumGetPointer(datum))))
1042                                                         {
1043                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1044                                                                 if (!(TupIsNull(newSlot)))
1045                                                                 {
1046                                                                         slot = newSlot;
1047                                                                         estate->es_useEvalPlan = true;
1048                                                                         goto lmark;
1049                                                                 }
1050                                                         }
1051
1052                                                         /*
1053                                                          * if tuple was deleted or PlanQual failed for
1054                                                          * updated tuple - we must not return this
1055                                                          * tuple!
1056                                                          */
1057                                                         goto lnext;
1058
1059                                                 default:
1060                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1061                                                         return (NULL);
1062                                         }
1063                                 }
1064                         }
1065
1066                         /*
1067                          * Finally create a new "clean" tuple with all junk attributes
1068                          * removed
1069                          */
1070                         newTuple = ExecRemoveJunk(junkfilter, slot);
1071
1072                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1073                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1074                                                                   InvalidBuffer,                /* this tuple has no
1075                                                                                                                  * buffer */
1076                                                                   true);                /* tuple should be pfreed */
1077                 }
1078
1079                 /*
1080                  * now that we have a tuple, do the appropriate thing with it..
1081                  * either return it to the user, add it to a relation someplace,
1082                  * delete it from a relation, or modify some of its attributes.
1083                  */
1084                 switch (operation)
1085                 {
1086                         case CMD_SELECT:
1087                                 ExecSelect(slot,        /* slot containing tuple */
1088                                                    destfunc,    /* destination's tuple-receiver
1089                                                                                  * obj */
1090                                                    estate);
1091                                 result = slot;
1092                                 break;
1093
1094                         case CMD_INSERT:
1095                                 ExecInsert(slot, tupleid, estate);
1096                                 result = NULL;
1097                                 break;
1098
1099                         case CMD_DELETE:
1100                                 ExecDelete(slot, tupleid, estate);
1101                                 result = NULL;
1102                                 break;
1103
1104                         case CMD_UPDATE:
1105                                 ExecUpdate(slot, tupleid, estate);
1106                                 result = NULL;
1107                                 break;
1108
1109                         default:
1110                                 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1111                                 result = NULL;
1112                                 break;
1113                 }
1114
1115                 /*
1116                  * check our tuple count.. if we've processed the proper number
1117                  * then quit, else loop again and process more tuples.  Zero
1118                  * number_tuples means no limit.
1119                  */
1120                 current_tuple_count++;
1121                 if (numberTuples == current_tuple_count)
1122                         break;
1123         }
1124
1125         /*
1126          * Process AFTER EACH STATEMENT triggers
1127          */
1128         switch (operation)
1129         {
1130                 case CMD_UPDATE:
1131                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1132                         break;
1133                 case CMD_DELETE:
1134                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1135                         break;
1136                 case CMD_INSERT:
1137                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1138                         break;
1139                 default:
1140                         /* do nothing */
1141                         break;
1142         }
1143
1144         /*
1145          * here, result is either a slot containing a tuple in the case of a
1146          * SELECT or NULL otherwise.
1147          */
1148         return result;
1149 }
1150
1151 /* ----------------------------------------------------------------
1152  *              ExecSelect
1153  *
1154  *              SELECTs are easy.. we just pass the tuple to the appropriate
1155  *              print function.  The only complexity is when we do a
1156  *              "SELECT INTO", in which case we insert the tuple into
1157  *              the appropriate relation (note: this is a newly created relation
1158  *              so we don't need to worry about indices or locks.)
1159  * ----------------------------------------------------------------
1160  */
1161 static void
1162 ExecSelect(TupleTableSlot *slot,
1163                    DestReceiver *destfunc,
1164                    EState *estate)
1165 {
1166         HeapTuple       tuple;
1167         TupleDesc       attrtype;
1168
1169         /*
1170          * get the heap tuple out of the tuple table slot
1171          */
1172         tuple = slot->val;
1173         attrtype = slot->ttc_tupleDescriptor;
1174
1175         /*
1176          * insert the tuple into the "into relation"
1177          */
1178         if (estate->es_into_relation_descriptor != NULL)
1179         {
1180                 heap_insert(estate->es_into_relation_descriptor, tuple,
1181                                         estate->es_snapshot->curcid);
1182                 IncrAppended();
1183         }
1184
1185         /*
1186          * send the tuple to the front end (or the screen)
1187          */
1188         (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1189         IncrRetrieved();
1190         (estate->es_processed)++;
1191 }
1192
1193 /* ----------------------------------------------------------------
1194  *              ExecInsert
1195  *
1196  *              INSERTs are trickier.. we have to insert the tuple into
1197  *              the base relation and insert appropriate tuples into the
1198  *              index relations.
1199  * ----------------------------------------------------------------
1200  */
1201 static void
1202 ExecInsert(TupleTableSlot *slot,
1203                    ItemPointer tupleid,
1204                    EState *estate)
1205 {
1206         HeapTuple       tuple;
1207         ResultRelInfo *resultRelInfo;
1208         Relation        resultRelationDesc;
1209         int                     numIndices;
1210         Oid                     newId;
1211
1212         /*
1213          * get the heap tuple out of the tuple table slot
1214          */
1215         tuple = slot->val;
1216
1217         /*
1218          * get information on the (current) result relation
1219          */
1220         resultRelInfo = estate->es_result_relation_info;
1221         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1222
1223         /* BEFORE ROW INSERT Triggers */
1224         if (resultRelInfo->ri_TrigDesc &&
1225                 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1226         {
1227                 HeapTuple       newtuple;
1228
1229                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1230
1231                 if (newtuple == NULL)   /* "do nothing" */
1232                         return;
1233
1234                 if (newtuple != tuple)  /* modified by Trigger(s) */
1235                 {
1236                         /*
1237                          * Insert modified tuple into tuple table slot, replacing the
1238                          * original.  We assume that it was allocated in per-tuple
1239                          * memory context, and therefore will go away by itself. The
1240                          * tuple table slot should not try to clear it.
1241                          */
1242                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1243                         tuple = newtuple;
1244                 }
1245         }
1246
1247         /*
1248          * Check the constraints of the tuple
1249          */
1250         if (resultRelationDesc->rd_att->constr)
1251                 ExecConstraints("ExecInsert", resultRelInfo, slot, estate);
1252
1253         /*
1254          * insert the tuple
1255          */
1256         newId = heap_insert(resultRelationDesc, tuple,
1257                                                 estate->es_snapshot->curcid);
1258
1259         IncrAppended();
1260         (estate->es_processed)++;
1261         estate->es_lastoid = newId;
1262         setLastTid(&(tuple->t_self));
1263
1264         /*
1265          * process indices
1266          *
1267          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1268          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1269          * field.
1270          */
1271         numIndices = resultRelInfo->ri_NumIndices;
1272         if (numIndices > 0)
1273                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1274
1275         /* AFTER ROW INSERT Triggers */
1276         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1277 }
1278
1279 /* ----------------------------------------------------------------
1280  *              ExecDelete
1281  *
1282  *              DELETE is like UPDATE, we delete the tuple and its
1283  *              index tuples.
1284  * ----------------------------------------------------------------
1285  */
1286 static void
1287 ExecDelete(TupleTableSlot *slot,
1288                    ItemPointer tupleid,
1289                    EState *estate)
1290 {
1291         ResultRelInfo *resultRelInfo;
1292         Relation        resultRelationDesc;
1293         ItemPointerData ctid;
1294         int                     result;
1295
1296         /*
1297          * get information on the (current) result relation
1298          */
1299         resultRelInfo = estate->es_result_relation_info;
1300         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1301
1302         /* BEFORE ROW DELETE Triggers */
1303         if (resultRelInfo->ri_TrigDesc &&
1304           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1305         {
1306                 bool            dodelete;
1307
1308                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
1309
1310                 if (!dodelete)                  /* "do nothing" */
1311                         return;
1312         }
1313
1314         /*
1315          * delete the tuple
1316          */
1317 ldelete:;
1318         result = heap_delete(resultRelationDesc, tupleid,
1319                                                  &ctid,
1320                                                  estate->es_snapshot->curcid);
1321         switch (result)
1322         {
1323                 case HeapTupleSelfUpdated:
1324                         /* already deleted by self; nothing to do */
1325                         return;
1326
1327                 case HeapTupleMayBeUpdated:
1328                         break;
1329
1330                 case HeapTupleUpdated:
1331                         if (XactIsoLevel == XACT_SERIALIZABLE)
1332                                 elog(ERROR, "Can't serialize access due to concurrent update");
1333                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1334                         {
1335                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1336                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1337
1338                                 if (!TupIsNull(epqslot))
1339                                 {
1340                                         *tupleid = ctid;
1341                                         goto ldelete;
1342                                 }
1343                         }
1344                         /* tuple already deleted; nothing to do */
1345                         return;
1346
1347                 default:
1348                         elog(ERROR, "Unknown status %u from heap_delete", result);
1349                         return;
1350         }
1351
1352         IncrDeleted();
1353         (estate->es_processed)++;
1354
1355         /*
1356          * Note: Normally one would think that we have to delete index tuples
1357          * associated with the heap tuple now..
1358          *
1359          * ... but in POSTGRES, we have no need to do this because the vacuum
1360          * daemon automatically opens an index scan and deletes index tuples
1361          * when it finds deleted heap tuples. -cim 9/27/89
1362          */
1363
1364         /* AFTER ROW DELETE Triggers */
1365         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1366 }
1367
1368 /* ----------------------------------------------------------------
1369  *              ExecUpdate
1370  *
1371  *              note: we can't run UPDATE queries with transactions
1372  *              off because UPDATEs are actually INSERTs and our
1373  *              scan will mistakenly loop forever, updating the tuple
1374  *              it just inserted..      This should be fixed but until it
1375  *              is, we don't want to get stuck in an infinite loop
1376  *              which corrupts your database..
1377  * ----------------------------------------------------------------
1378  */
1379 static void
1380 ExecUpdate(TupleTableSlot *slot,
1381                    ItemPointer tupleid,
1382                    EState *estate)
1383 {
1384         HeapTuple       tuple;
1385         ResultRelInfo *resultRelInfo;
1386         Relation        resultRelationDesc;
1387         ItemPointerData ctid;
1388         int                     result;
1389         int                     numIndices;
1390
1391         /*
1392          * abort the operation if not running transactions
1393          */
1394         if (IsBootstrapProcessingMode())
1395         {
1396                 elog(WARNING, "ExecUpdate: UPDATE can't run without transactions");
1397                 return;
1398         }
1399
1400         /*
1401          * get the heap tuple out of the tuple table slot
1402          */
1403         tuple = slot->val;
1404
1405         /*
1406          * get information on the (current) result relation
1407          */
1408         resultRelInfo = estate->es_result_relation_info;
1409         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1410
1411         /* BEFORE ROW UPDATE Triggers */
1412         if (resultRelInfo->ri_TrigDesc &&
1413           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1414         {
1415                 HeapTuple       newtuple;
1416
1417                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1418                                                                                 tupleid, tuple);
1419
1420                 if (newtuple == NULL)   /* "do nothing" */
1421                         return;
1422
1423                 if (newtuple != tuple)  /* modified by Trigger(s) */
1424                 {
1425                         /*
1426                          * Insert modified tuple into tuple table slot, replacing the
1427                          * original.  We assume that it was allocated in per-tuple
1428                          * memory context, and therefore will go away by itself. The
1429                          * tuple table slot should not try to clear it.
1430                          */
1431                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1432                         tuple = newtuple;
1433                 }
1434         }
1435
1436         /*
1437          * Check the constraints of the tuple
1438          *
1439          * If we generate a new candidate tuple after EvalPlanQual testing, we
1440          * must loop back here and recheck constraints.  (We don't need to
1441          * redo triggers, however.      If there are any BEFORE triggers then
1442          * trigger.c will have done mark4update to lock the correct tuple, so
1443          * there's no need to do them again.)
1444          */
1445 lreplace:;
1446         if (resultRelationDesc->rd_att->constr)
1447                 ExecConstraints("ExecUpdate", resultRelInfo, slot, estate);
1448
1449         /*
1450          * replace the heap tuple
1451          */
1452         result = heap_update(resultRelationDesc, tupleid, tuple,
1453                                                  &ctid,
1454                                                  estate->es_snapshot->curcid);
1455         switch (result)
1456         {
1457                 case HeapTupleSelfUpdated:
1458                         /* already deleted by self; nothing to do */
1459                         return;
1460
1461                 case HeapTupleMayBeUpdated:
1462                         break;
1463
1464                 case HeapTupleUpdated:
1465                         if (XactIsoLevel == XACT_SERIALIZABLE)
1466                                 elog(ERROR, "Can't serialize access due to concurrent update");
1467                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1468                         {
1469                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1470                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1471
1472                                 if (!TupIsNull(epqslot))
1473                                 {
1474                                         *tupleid = ctid;
1475                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1476                                         slot = ExecStoreTuple(tuple,
1477                                                                         estate->es_junkFilter->jf_resultSlot,
1478                                                                                   InvalidBuffer, true);
1479                                         goto lreplace;
1480                                 }
1481                         }
1482                         /* tuple already deleted; nothing to do */
1483                         return;
1484
1485                 default:
1486                         elog(ERROR, "Unknown status %u from heap_update", result);
1487                         return;
1488         }
1489
1490         IncrReplaced();
1491         (estate->es_processed)++;
1492
1493         /*
1494          * Note: instead of having to update the old index tuples associated
1495          * with the heap tuple, all we do is form and insert new index tuples.
1496          * This is because UPDATEs are actually DELETEs and INSERTs and index
1497          * tuple deletion is done automagically by the vacuum daemon. All we
1498          * do is insert new index tuples.  -cim 9/27/89
1499          */
1500
1501         /*
1502          * process indices
1503          *
1504          * heap_update updates a tuple in the base relation by invalidating it
1505          * and then inserting a new tuple to the relation.      As a side effect,
1506          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1507          * field.  So we now insert index tuples using the new tupleid stored
1508          * there.
1509          */
1510
1511         numIndices = resultRelInfo->ri_NumIndices;
1512         if (numIndices > 0)
1513                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1514
1515         /* AFTER ROW UPDATE Triggers */
1516         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1517 }
1518
1519 static char *
1520 ExecRelCheck(ResultRelInfo *resultRelInfo,
1521                          TupleTableSlot *slot, EState *estate)
1522 {
1523         Relation        rel = resultRelInfo->ri_RelationDesc;
1524         int                     ncheck = rel->rd_att->constr->num_check;
1525         ConstrCheck *check = rel->rd_att->constr->check;
1526         ExprContext *econtext;
1527         MemoryContext oldContext;
1528         List       *qual;
1529         int                     i;
1530
1531         /*
1532          * If first time through for this result relation, build expression
1533          * nodetrees for rel's constraint expressions.  Keep them in the
1534          * per-query memory context so they'll survive throughout the query.
1535          */
1536         if (resultRelInfo->ri_ConstraintExprs == NULL)
1537         {
1538                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1539                 resultRelInfo->ri_ConstraintExprs =
1540                         (List **) palloc(ncheck * sizeof(List *));
1541                 for (i = 0; i < ncheck; i++)
1542                 {
1543                         qual = (List *) stringToNode(check[i].ccbin);
1544                         resultRelInfo->ri_ConstraintExprs[i] = qual;
1545                 }
1546                 MemoryContextSwitchTo(oldContext);
1547         }
1548
1549         /*
1550          * We will use the EState's per-tuple context for evaluating
1551          * constraint expressions (creating it if it's not already there).
1552          */
1553         econtext = GetPerTupleExprContext(estate);
1554
1555         /* Arrange for econtext's scan tuple to be the tuple under test */
1556         econtext->ecxt_scantuple = slot;
1557
1558         /* And evaluate the constraints */
1559         for (i = 0; i < ncheck; i++)
1560         {
1561                 qual = resultRelInfo->ri_ConstraintExprs[i];
1562
1563                 /*
1564                  * NOTE: SQL92 specifies that a NULL result from a constraint
1565                  * expression is not to be treated as a failure.  Therefore, tell
1566                  * ExecQual to return TRUE for NULL.
1567                  */
1568                 if (!ExecQual(qual, econtext, true))
1569                         return check[i].ccname;
1570         }
1571
1572         /* NULL result means no error */
1573         return (char *) NULL;
1574 }
1575
1576 void
1577 ExecConstraints(const char *caller, ResultRelInfo *resultRelInfo,
1578                                 TupleTableSlot *slot, EState *estate)
1579 {
1580         Relation        rel = resultRelInfo->ri_RelationDesc;
1581         HeapTuple       tuple = slot->val;
1582         TupleConstr *constr = rel->rd_att->constr;
1583
1584         Assert(constr);
1585
1586         if (constr->has_not_null)
1587         {
1588                 int                     natts = rel->rd_att->natts;
1589                 int                     attrChk;
1590
1591                 for (attrChk = 1; attrChk <= natts; attrChk++)
1592                 {
1593                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1594                                 heap_attisnull(tuple, attrChk))
1595                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1596                                          caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1597                 }
1598         }
1599
1600         if (constr->num_check > 0)
1601         {
1602                 char       *failed;
1603
1604                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1605                         elog(ERROR, "%s: rejected due to CHECK constraint \"%s\" on \"%s\"",
1606                                  caller, failed, RelationGetRelationName(rel));
1607         }
1608 }
1609
1610 /*
1611  * Check a modified tuple to see if we want to process its updated version
1612  * under READ COMMITTED rules.
1613  *
1614  * See backend/executor/README for some info about how this works.
1615  */
1616 TupleTableSlot *
1617 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1618 {
1619         evalPlanQual *epq;
1620         EState     *epqstate;
1621         Relation        relation;
1622         HeapTupleData tuple;
1623         HeapTuple       copyTuple = NULL;
1624         int                     rtsize;
1625         bool            endNode;
1626
1627         Assert(rti != 0);
1628
1629         /*
1630          * find relation containing target tuple
1631          */
1632         if (estate->es_result_relation_info != NULL &&
1633                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1634                 relation = estate->es_result_relation_info->ri_RelationDesc;
1635         else
1636         {
1637                 List       *l;
1638
1639                 relation = NULL;
1640                 foreach(l, estate->es_rowMark)
1641                 {
1642                         if (((execRowMark *) lfirst(l))->rti == rti)
1643                         {
1644                                 relation = ((execRowMark *) lfirst(l))->relation;
1645                                 break;
1646                         }
1647                 }
1648                 if (relation == NULL)
1649                         elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1650         }
1651
1652         /*
1653          * fetch tid tuple
1654          *
1655          * Loop here to deal with updated or busy tuples
1656          */
1657         tuple.t_self = *tid;
1658         for (;;)
1659         {
1660                 Buffer          buffer;
1661
1662                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1663                 {
1664                         TransactionId xwait = SnapshotDirty->xmax;
1665
1666                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1667                                 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1668
1669                         /*
1670                          * If tuple is being updated by other transaction then we have
1671                          * to wait for its commit/abort.
1672                          */
1673                         if (TransactionIdIsValid(xwait))
1674                         {
1675                                 ReleaseBuffer(buffer);
1676                                 XactLockTableWait(xwait);
1677                                 continue;
1678                         }
1679
1680                         /*
1681                          * We got tuple - now copy it for use by recheck query.
1682                          */
1683                         copyTuple = heap_copytuple(&tuple);
1684                         ReleaseBuffer(buffer);
1685                         break;
1686                 }
1687
1688                 /*
1689                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1690                  * Note that it's possible to get invalid SnapshotDirty->tid if
1691                  * tuple updated by this transaction. Have we to check this ?
1692                  */
1693                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1694                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1695                 {
1696                         /* updated, so look at the updated copy */
1697                         tuple.t_self = SnapshotDirty->tid;
1698                         continue;
1699                 }
1700
1701                 /*
1702                  * Deleted or updated by this transaction; forget it.
1703                  */
1704                 return NULL;
1705         }
1706
1707         /*
1708          * For UPDATE/DELETE we have to return tid of actual row we're
1709          * executing PQ for.
1710          */
1711         *tid = tuple.t_self;
1712
1713         /*
1714          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1715          */
1716         epq = (evalPlanQual *) estate->es_evalPlanQual;
1717         rtsize = length(estate->es_range_table);
1718         endNode = true;
1719
1720         if (epq != NULL && epq->rti == 0)
1721         {
1722                 /* Top PQ stack entry is idle, so re-use it */
1723                 Assert(!(estate->es_useEvalPlan) &&
1724                            epq->estate.es_evalPlanQual == NULL);
1725                 epq->rti = rti;
1726                 endNode = false;
1727         }
1728
1729         /*
1730          * If this is request for another RTE - Ra, - then we have to check
1731          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1732          * updated again and we have to re-start old execution for Ra and
1733          * forget all what we done after Ra was suspended. Cool? -:))
1734          */
1735         if (epq != NULL && epq->rti != rti &&
1736                 epq->estate.es_evTuple[rti - 1] != NULL)
1737         {
1738                 do
1739                 {
1740                         evalPlanQual *oldepq;
1741
1742                         /* pop previous PlanQual from the stack */
1743                         epqstate = &(epq->estate);
1744                         oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1745                         Assert(oldepq->rti != 0);
1746                         /* stop execution */
1747                         ExecEndNode(epq->planstate);
1748                         ExecDropTupleTable(epqstate->es_tupleTable, true);
1749                         epqstate->es_tupleTable = NULL;
1750                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1751                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1752                         /* push current PQ to freePQ stack */
1753                         oldepq->free = epq;
1754                         epq = oldepq;
1755                         estate->es_evalPlanQual = (Pointer) epq;
1756                 } while (epq->rti != rti);
1757         }
1758
1759         /*
1760          * If we are requested for another RTE then we have to suspend
1761          * execution of current PlanQual and start execution for new one.
1762          */
1763         if (epq == NULL || epq->rti != rti)
1764         {
1765                 /* try to reuse plan used previously */
1766                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1767
1768                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1769                 {
1770                         newepq = (evalPlanQual *) palloc(sizeof(evalPlanQual));
1771                         newepq->free = NULL;
1772
1773                         /*
1774                          * Each stack level has its own copy of the plan tree.  This
1775                          * is wasteful, but necessary until plan trees are fully
1776                          * read-only.
1777                          */
1778                         newepq->plan = copyObject(estate->es_origPlan);
1779
1780                         /*
1781                          * Init stack level's EState.  We share top level's copy of
1782                          * es_result_relations array and other non-changing status. We
1783                          * need our own tupletable, es_param_exec_vals, and other
1784                          * changeable state.
1785                          */
1786                         epqstate = &(newepq->estate);
1787                         memcpy(epqstate, estate, sizeof(EState));
1788                         epqstate->es_direction = ForwardScanDirection;
1789                         if (estate->es_origPlan->nParamExec > 0)
1790                                 epqstate->es_param_exec_vals = (ParamExecData *)
1791                                         palloc(estate->es_origPlan->nParamExec *
1792                                                    sizeof(ParamExecData));
1793                         epqstate->es_tupleTable = NULL;
1794                         epqstate->es_per_tuple_exprcontext = NULL;
1795
1796                         /*
1797                          * Each epqstate must have its own es_evTupleNull state, but
1798                          * all the stack entries share es_evTuple state.  This allows
1799                          * sub-rechecks to inherit the value being examined by an
1800                          * outer recheck.
1801                          */
1802                         epqstate->es_evTupleNull = (bool *) palloc(rtsize * sizeof(bool));
1803                         if (epq == NULL)
1804                                 /* first PQ stack entry */
1805                                 epqstate->es_evTuple = (HeapTuple *)
1806                                         palloc0(rtsize * sizeof(HeapTuple));
1807                         else
1808                                 /* later stack entries share the same storage */
1809                                 epqstate->es_evTuple = epq->estate.es_evTuple;
1810                 }
1811                 else
1812                 {
1813                         /* recycle previously used EState */
1814                         epqstate = &(newepq->estate);
1815                 }
1816                 /* push current PQ to the stack */
1817                 epqstate->es_evalPlanQual = (Pointer) epq;
1818                 epq = newepq;
1819                 estate->es_evalPlanQual = (Pointer) epq;
1820                 epq->rti = rti;
1821                 endNode = false;
1822         }
1823
1824         Assert(epq->rti == rti);
1825         epqstate = &(epq->estate);
1826
1827         /*
1828          * Ok - we're requested for the same RTE.  Unfortunately we still have
1829          * to end and restart execution of the plan, because ExecReScan
1830          * wouldn't ensure that upper plan nodes would reset themselves.  We
1831          * could make that work if insertion of the target tuple were
1832          * integrated with the Param mechanism somehow, so that the upper plan
1833          * nodes know that their children's outputs have changed.
1834          */
1835         if (endNode)
1836         {
1837                 /* stop execution */
1838                 ExecEndNode(epq->planstate);
1839                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1840                 epqstate->es_tupleTable = NULL;
1841         }
1842
1843         /*
1844          * free old RTE' tuple, if any, and store target tuple where
1845          * relation's scan node will see it
1846          */
1847         if (epqstate->es_evTuple[rti - 1] != NULL)
1848                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1849         epqstate->es_evTuple[rti - 1] = copyTuple;
1850
1851         /*
1852          * Initialize for new recheck query; be careful to copy down state
1853          * that might have changed in top EState.
1854          */
1855         epqstate->es_result_relation_info = estate->es_result_relation_info;
1856         epqstate->es_junkFilter = estate->es_junkFilter;
1857         if (estate->es_origPlan->nParamExec > 0)
1858                 memset(epqstate->es_param_exec_vals, 0,
1859                            estate->es_origPlan->nParamExec * sizeof(ParamExecData));
1860         memset(epqstate->es_evTupleNull, false, rtsize * sizeof(bool));
1861         epqstate->es_useEvalPlan = false;
1862         Assert(epqstate->es_tupleTable == NULL);
1863         epqstate->es_tupleTable =
1864                 ExecCreateTupleTable(estate->es_tupleTable->size);
1865
1866         epq->planstate = ExecInitNode(epq->plan, epqstate);
1867
1868         return EvalPlanQualNext(estate);
1869 }
1870
1871 static TupleTableSlot *
1872 EvalPlanQualNext(EState *estate)
1873 {
1874         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1875         EState     *epqstate = &(epq->estate);
1876         evalPlanQual *oldepq;
1877         TupleTableSlot *slot;
1878
1879         Assert(epq->rti != 0);
1880
1881 lpqnext:;
1882         slot = ExecProcNode(epq->planstate);
1883
1884         /*
1885          * No more tuples for this PQ. Continue previous one.
1886          */
1887         if (TupIsNull(slot))
1888         {
1889                 /* stop execution */
1890                 ExecEndNode(epq->planstate);
1891                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1892                 epqstate->es_tupleTable = NULL;
1893                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1894                 epqstate->es_evTuple[epq->rti - 1] = NULL;
1895                 /* pop old PQ from the stack */
1896                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1897                 if (oldepq == (evalPlanQual *) NULL)
1898                 {
1899                         epq->rti = 0;           /* this is the first (oldest) */
1900                         estate->es_useEvalPlan = false;         /* PQ - mark as free and          */
1901                         return (NULL);          /* continue Query execution   */
1902                 }
1903                 Assert(oldepq->rti != 0);
1904                 /* push current PQ to freePQ stack */
1905                 oldepq->free = epq;
1906                 epq = oldepq;
1907                 epqstate = &(epq->estate);
1908                 estate->es_evalPlanQual = (Pointer) epq;
1909                 goto lpqnext;
1910         }
1911
1912         return (slot);
1913 }
1914
1915 static void
1916 EndEvalPlanQual(EState *estate)
1917 {
1918         evalPlanQual *epq = (evalPlanQual *) estate->es_evalPlanQual;
1919         EState     *epqstate = &(epq->estate);
1920         evalPlanQual *oldepq;
1921
1922         if (epq->rti == 0)                      /* plans already shutdowned */
1923         {
1924                 Assert(epq->estate.es_evalPlanQual == NULL);
1925                 return;
1926         }
1927
1928         for (;;)
1929         {
1930                 /* stop execution */
1931                 ExecEndNode(epq->planstate);
1932                 ExecDropTupleTable(epqstate->es_tupleTable, true);
1933                 epqstate->es_tupleTable = NULL;
1934                 if (epqstate->es_evTuple[epq->rti - 1] != NULL)
1935                 {
1936                         heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
1937                         epqstate->es_evTuple[epq->rti - 1] = NULL;
1938                 }
1939                 /* pop old PQ from the stack */
1940                 oldepq = (evalPlanQual *) epqstate->es_evalPlanQual;
1941                 if (oldepq == (evalPlanQual *) NULL)
1942                 {
1943                         epq->rti = 0;           /* this is the first (oldest) */
1944                         estate->es_useEvalPlan = false;         /* PQ - mark as free */
1945                         break;
1946                 }
1947                 Assert(oldepq->rti != 0);
1948                 /* push current PQ to freePQ stack */
1949                 oldepq->free = epq;
1950                 epq = oldepq;
1951                 epqstate = &(epq->estate);
1952                 estate->es_evalPlanQual = (Pointer) epq;
1953         }
1954 }