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  11  *      The old ExecutorMain() has been replaced by ExecutorStart(),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 1.199 2003/01/23 05:10:37 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, (int) operation,
 221                                                 queryDesc->portalName, 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 /*
 292  * ExecCheckRTPerms
 293  *              Check access permissions for all relations listed in a range table.
 294  */
 295 void
 296 ExecCheckRTPerms(List *rangeTable, CmdType operation)
 297 {
 298         List       *lp;
 299
 300         foreach(lp, rangeTable)
 301         {
 302                 RangeTblEntry *rte = lfirst(lp);
 303
 304                 ExecCheckRTEPerms(rte, operation);
 305         }
 306 }
 307
 308 /*
 309  * ExecCheckRTEPerms
 310  *              Check access permissions for a single RTE.
 311  */
 312 static void
 313 ExecCheckRTEPerms(RangeTblEntry *rte, CmdType operation)
 314 {
 315         Oid                     relOid;
 316         AclId           userid;
 317         AclResult       aclcheck_result;
 318
 319         /*
 320          * If it's a subquery, recursively examine its rangetable.
 321          */
 322         if (rte->rtekind == RTE_SUBQUERY)
 323         {
 324                 ExecCheckRTPerms(rte->subquery->rtable, operation);
 325                 return;
 326         }
 327
 328         /*
 329          * Otherwise, only plain-relation RTEs need to be checked here.
 330          * Function RTEs are checked by init_fcache when the function is prepared
 331          * for execution. Join and special RTEs need no checks.
 332          */
 333         if (rte->rtekind != RTE_RELATION)
 334                 return;
 335
 336         relOid = rte->relid;
 337
 338         /*
 339          * userid to check as: current user unless we have a setuid
 340          * indication.
 341          *
 342          * Note: GetUserId() is presently fast enough that there's no harm in
 343          * calling it separately for each RTE.  If that stops being true, we
 344          * could call it once in ExecCheckRTPerms and pass the userid down
 345          * from there.  But for now, no need for the extra clutter.
 346          */
 347         userid = rte->checkAsUser ? rte->checkAsUser : GetUserId();
 348
 349 #define CHECK(MODE)             pg_class_aclcheck(relOid, userid, MODE)
 350
 351         if (rte->checkForRead)
 352         {
 353                 aclcheck_result = CHECK(ACL_SELECT);
 354                 if (aclcheck_result != ACLCHECK_OK)
 355                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 356         }
 357
 358         if (rte->checkForWrite)
 359         {
 360                 /*
 361                  * Note: write access in a SELECT context means SELECT FOR UPDATE.
 362                  * Right now we don't distinguish that from true update as far as
 363                  * permissions checks are concerned.
 364                  */
 365                 switch (operation)
 366                 {
 367                         case CMD_INSERT:
 368                                 aclcheck_result = CHECK(ACL_INSERT);
 369                                 break;
 370                         case CMD_SELECT:
 371                         case CMD_UPDATE:
 372                                 aclcheck_result = CHECK(ACL_UPDATE);
 373                                 break;
 374                         case CMD_DELETE:
 375                                 aclcheck_result = CHECK(ACL_DELETE);
 376                                 break;
 377                         default:
 378                                 elog(ERROR, "ExecCheckRTEPerms: bogus operation %d",
 379                                          operation);
 380                                 aclcheck_result = ACLCHECK_OK;  /* keep compiler quiet */
 381                                 break;
 382                 }
 383                 if (aclcheck_result != ACLCHECK_OK)
 384                         aclcheck_error(aclcheck_result, get_rel_name(relOid));
 385         }
 386 }
 387
 388
 389 /* ===============================================================
 390  * ===============================================================
 391                                                  static routines follow
 392  * ===============================================================
 393  * ===============================================================
 394  */
 395
 396
 397 static void
 398 ExecCheckXactReadOnly(Query *parsetree, CmdType operation)
 399 {
 400         if (!XactReadOnly)
 401                 return;
 402
 403         /* CREATE TABLE AS or SELECT INTO */
 404         if (operation == CMD_SELECT && parsetree->into != NULL)
 405                 goto fail;
 406
 407         if (operation == CMD_DELETE || operation == CMD_INSERT
 408                 || operation == CMD_UPDATE)
 409         {
 410                 List *lp;
 411
 412                 foreach(lp, parsetree->rtable)
 413                 {
 414                         RangeTblEntry *rte = lfirst(lp);
 415
 416                         if (rte->rtekind != RTE_RELATION)
 417                                 continue;
 418
 419                         if (!rte->checkForWrite)
 420                                 continue;
 421
 422                         if (isTempNamespace(get_rel_namespace(rte->relid)))
 423                                 continue;
 424
 425                         goto fail;
 426                 }
 427         }
 428
 429         return;
 430
 431 fail:
 432         elog(ERROR, "transaction is read-only");
 433 }
 434
 435
 436 /* ----------------------------------------------------------------
 437  *              InitPlan
 438  *
 439  *              Initializes the query plan: open files, allocate storage
 440  *              and start up the rule manager
 441  * ----------------------------------------------------------------
 442  */
 443 static void
 444 InitPlan(QueryDesc *queryDesc)
 445 {
 446         CmdType         operation = queryDesc->operation;
 447         Query *parseTree = queryDesc->parsetree;
 448         Plan *plan = queryDesc->plantree;
 449         EState *estate = queryDesc->estate;
 450         PlanState  *planstate;
 451         List       *rangeTable;
 452         Relation        intoRelationDesc;
 453         bool            do_select_into;
 454         TupleDesc       tupType;
 455
 456         /*
 457          * Do permissions checks.  It's sufficient to examine the query's
 458          * top rangetable here --- subplan RTEs will be checked during
 459          * ExecInitSubPlan().
 460          */
 461         ExecCheckRTPerms(parseTree->rtable, operation);
 462
 463         /*
 464          * get information from query descriptor
 465          */
 466         rangeTable = parseTree->rtable;
 467
 468         /*
 469          * initialize the node's execution state
 470          */
 471         estate->es_range_table = rangeTable;
 472
 473         /*
 474          * if there is a result relation, initialize result relation stuff
 475          */
 476         if (parseTree->resultRelation != 0 && operation != CMD_SELECT)
 477         {
 478                 List       *resultRelations = parseTree->resultRelations;
 479                 int                     numResultRelations;
 480                 ResultRelInfo *resultRelInfos;
 481
 482                 if (resultRelations != NIL)
 483                 {
 484                         /*
 485                          * Multiple result relations (due to inheritance)
 486                          * parseTree->resultRelations identifies them all
 487                          */
 488                         ResultRelInfo *resultRelInfo;
 489
 490                         numResultRelations = length(resultRelations);
 491                         resultRelInfos = (ResultRelInfo *)
 492                                 palloc(numResultRelations * sizeof(ResultRelInfo));
 493                         resultRelInfo = resultRelInfos;
 494                         while (resultRelations != NIL)
 495                         {
 496                                 initResultRelInfo(resultRelInfo,
 497                                                                   lfirsti(resultRelations),
 498                                                                   rangeTable,
 499                                                                   operation);
 500                                 resultRelInfo++;
 501                                 resultRelations = lnext(resultRelations);
 502                         }
 503                 }
 504                 else
 505                 {
 506                         /*
 507                          * Single result relation identified by
 508                          * parseTree->resultRelation
 509                          */
 510                         numResultRelations = 1;
 511                         resultRelInfos = (ResultRelInfo *) palloc(sizeof(ResultRelInfo));
 512                         initResultRelInfo(resultRelInfos,
 513                                                           parseTree->resultRelation,
 514                                                           rangeTable,
 515                                                           operation);
 516                 }
 517
 518                 estate->es_result_relations = resultRelInfos;
 519                 estate->es_num_result_relations = numResultRelations;
 520                 /* Initialize to first or only result rel */
 521                 estate->es_result_relation_info = resultRelInfos;
 522         }
 523         else
 524         {
 525                 /*
 526                  * if no result relation, then set state appropriately
 527                  */
 528                 estate->es_result_relations = NULL;
 529                 estate->es_num_result_relations = 0;
 530                 estate->es_result_relation_info = NULL;
 531         }
 532
 533         /*
 534          * Detect whether we're doing SELECT INTO.  If so, set the force_oids
 535          * flag appropriately so that the plan tree will be initialized with
 536          * the correct tuple descriptors.
 537          */
 538         do_select_into = false;
 539
 540         if (operation == CMD_SELECT &&
 541                 !parseTree->isPortal &&
 542                 parseTree->into != NULL)
 543         {
 544                 do_select_into = true;
 545                 /*
 546                  * For now, always create OIDs in SELECT INTO; this is for backwards
 547                  * compatibility with pre-7.3 behavior.  Eventually we might want
 548                  * to allow the user to choose.
 549                  */
 550                 estate->es_force_oids = true;
 551         }
 552
 553         /*
 554          * Have to lock relations selected for update
 555          */
 556         estate->es_rowMark = NIL;
 557         if (parseTree->rowMarks != NIL)
 558         {
 559                 List       *l;
 560
 561                 foreach(l, parseTree->rowMarks)
 562                 {
 563                         Index           rti = lfirsti(l);
 564                         Oid                     relid = getrelid(rti, rangeTable);
 565                         Relation        relation;
 566                         execRowMark *erm;
 567
 568                         relation = heap_open(relid, RowShareLock);
 569                         erm = (execRowMark *) palloc(sizeof(execRowMark));
 570                         erm->relation = relation;
 571                         erm->rti = rti;
 572                         snprintf(erm->resname, 32, "ctid%u", rti);
 573                         estate->es_rowMark = lappend(estate->es_rowMark, erm);
 574                 }
 575         }
 576
 577         /*
 578          * initialize the executor "tuple" table.  We need slots for all the
 579          * plan nodes, plus possibly output slots for the junkfilter(s). At
 580          * this point we aren't sure if we need junkfilters, so just add slots
 581          * for them unconditionally.
 582          */
 583         {
 584                 int                     nSlots = ExecCountSlotsNode(plan);
 585
 586                 if (parseTree->resultRelations != NIL)
 587                         nSlots += length(parseTree->resultRelations);
 588                 else
 589                         nSlots += 1;
 590                 estate->es_tupleTable = ExecCreateTupleTable(nSlots);
 591         }
 592
 593         /* mark EvalPlanQual not active */
 594         estate->es_topPlan = plan;
 595         estate->es_evalPlanQual = NULL;
 596         estate->es_evTupleNull = NULL;
 597         estate->es_evTuple = NULL;
 598         estate->es_useEvalPlan = false;
 599
 600         /*
 601          * initialize the private state information for all the nodes in the
 602          * query tree.  This opens files, allocates storage and leaves us
 603          * ready to start processing tuples.
 604          */
 605         planstate = ExecInitNode(plan, estate);
 606
 607         /*
 608          * Get the tuple descriptor describing the type of tuples to return.
 609          * (this is especially important if we are creating a relation with
 610          * "SELECT INTO")
 611          */
 612         tupType = ExecGetTupType(planstate);
 613
 614         /*
 615          * Initialize the junk filter if needed. SELECT and INSERT queries
 616          * need a filter if there are any junk attrs in the tlist.      UPDATE and
 617          * DELETE always need one, since there's always a junk 'ctid'
 618          * attribute present --- no need to look first.
 619          */
 620         {
 621                 bool            junk_filter_needed = false;
 622                 List       *tlist;
 623
 624                 switch (operation)
 625                 {
 626                         case CMD_SELECT:
 627                         case CMD_INSERT:
 628                                 foreach(tlist, plan->targetlist)
 629                                 {
 630                                         TargetEntry *tle = (TargetEntry *) lfirst(tlist);
 631
 632                                         if (tle->resdom->resjunk)
 633                                         {
 634                                                 junk_filter_needed = true;
 635                                                 break;
 636                                         }
 637                                 }
 638                                 break;
 639                         case CMD_UPDATE:
 640                         case CMD_DELETE:
 641                                 junk_filter_needed = true;
 642                                 break;
 643                         default:
 644                                 break;
 645                 }
 646
 647                 if (junk_filter_needed)
 648                 {
 649                         /*
 650                          * If there are multiple result relations, each one needs its
 651                          * own junk filter.  Note this is only possible for
 652                          * UPDATE/DELETE, so we can't be fooled by some needing a
 653                          * filter and some not.
 654                          */
 655                         if (parseTree->resultRelations != NIL)
 656                         {
 657                                 PlanState **appendplans;
 658                                 int                     as_nplans;
 659                                 ResultRelInfo *resultRelInfo;
 660                                 int                     i;
 661
 662                                 /* Top plan had better be an Append here. */
 663                                 Assert(IsA(plan, Append));
 664                                 Assert(((Append *) plan)->isTarget);
 665                                 Assert(IsA(planstate, AppendState));
 666                                 appendplans = ((AppendState *) planstate)->appendplans;
 667                                 as_nplans = ((AppendState *) planstate)->as_nplans;
 668                                 Assert(as_nplans == estate->es_num_result_relations);
 669                                 resultRelInfo = estate->es_result_relations;
 670                                 for (i = 0; i < as_nplans; i++)
 671                                 {
 672                                         PlanState  *subplan = appendplans[i];
 673                                         JunkFilter *j;
 674
 675                                         j = ExecInitJunkFilter(subplan->plan->targetlist,
 676                                                                                    ExecGetTupType(subplan),
 677                                                           ExecAllocTableSlot(estate->es_tupleTable));
 678                                         resultRelInfo->ri_junkFilter = j;
 679                                         resultRelInfo++;
 680                                 }
 681
 682                                 /*
 683                                  * Set active junkfilter too; at this point ExecInitAppend
 684                                  * has already selected an active result relation...
 685                                  */
 686                                 estate->es_junkFilter =
 687                                         estate->es_result_relation_info->ri_junkFilter;
 688                         }
 689                         else
 690                         {
 691                                 /* Normal case with just one JunkFilter */
 692                                 JunkFilter *j;
 693
 694                                 j = ExecInitJunkFilter(planstate->plan->targetlist,
 695                                                                            tupType,
 696                                                           ExecAllocTableSlot(estate->es_tupleTable));
 697                                 estate->es_junkFilter = j;
 698                                 if (estate->es_result_relation_info)
 699                                         estate->es_result_relation_info->ri_junkFilter = j;
 700
 701                                 /* For SELECT, want to return the cleaned tuple type */
 702                                 if (operation == CMD_SELECT)
 703                                         tupType = j->jf_cleanTupType;
 704                         }
 705                 }
 706                 else
 707                         estate->es_junkFilter = NULL;
 708         }
 709
 710         /*
 711          * If doing SELECT INTO, initialize the "into" relation.  We must wait
 712          * till now so we have the "clean" result tuple type to create the
 713          * new table from.
 714          */
 715         intoRelationDesc = (Relation) NULL;
 716
 717         if (do_select_into)
 718         {
 719                 char       *intoName;
 720                 Oid                     namespaceId;
 721                 AclResult       aclresult;
 722                 Oid                     intoRelationId;
 723                 TupleDesc       tupdesc;
 724
 725                 /*
 726                  * find namespace to create in, check permissions
 727                  */
 728                 intoName = parseTree->into->relname;
 729                 namespaceId = RangeVarGetCreationNamespace(parseTree->into);
 730
 731                 aclresult = pg_namespace_aclcheck(namespaceId, GetUserId(),
 732                                                                                   ACL_CREATE);
 733                 if (aclresult != ACLCHECK_OK)
 734                         aclcheck_error(aclresult, get_namespace_name(namespaceId));
 735
 736                 /*
 737                  * have to copy tupType to get rid of constraints
 738                  */
 739                 tupdesc = CreateTupleDescCopy(tupType);
 740
 741                 intoRelationId = heap_create_with_catalog(intoName,
 742                                                                                                   namespaceId,
 743                                                                                                   tupdesc,
 744                                                                                                   RELKIND_RELATION,
 745                                                                                                   false,
 746                                                                                                   ONCOMMIT_NOOP,
 747                                                                                                   allowSystemTableMods);
 748
 749                 FreeTupleDesc(tupdesc);
 750
 751                 /*
 752                  * Advance command counter so that the newly-created
 753                  * relation's catalog tuples will be visible to heap_open.
 754                  */
 755                 CommandCounterIncrement();
 756
 757                 /*
 758                  * If necessary, create a TOAST table for the into
 759                  * relation. Note that AlterTableCreateToastTable ends
 760                  * with CommandCounterIncrement(), so that the TOAST table
 761                  * will be visible for insertion.
 762                  */
 763                 AlterTableCreateToastTable(intoRelationId, true);
 764
 765                 /*
 766                  * And open the constructed table for writing.
 767                  */
 768                 intoRelationDesc = heap_open(intoRelationId, AccessExclusiveLock);
 769         }
 770
 771         estate->es_into_relation_descriptor = intoRelationDesc;
 772
 773         queryDesc->tupDesc = tupType;
 774         queryDesc->planstate = planstate;
 775 }
 776
 777 /*
 778  * Initialize ResultRelInfo data for one result relation
 779  */
 780 static void
 781 initResultRelInfo(ResultRelInfo *resultRelInfo,
 782                                   Index resultRelationIndex,
 783                                   List *rangeTable,
 784                                   CmdType operation)
 785 {
 786         Oid                     resultRelationOid;
 787         Relation        resultRelationDesc;
 788
 789         resultRelationOid = getrelid(resultRelationIndex, rangeTable);
 790         resultRelationDesc = heap_open(resultRelationOid, RowExclusiveLock);
 791
 792         switch (resultRelationDesc->rd_rel->relkind)
 793         {
 794                 case RELKIND_SEQUENCE:
 795                         elog(ERROR, "You can't change sequence relation %s",
 796                                  RelationGetRelationName(resultRelationDesc));
 797                         break;
 798                 case RELKIND_TOASTVALUE:
 799                         elog(ERROR, "You can't change toast relation %s",
 800                                  RelationGetRelationName(resultRelationDesc));
 801                         break;
 802                 case RELKIND_VIEW:
 803                         elog(ERROR, "You can't change view relation %s",
 804                                  RelationGetRelationName(resultRelationDesc));
 805                         break;
 806         }
 807
 808         MemSet(resultRelInfo, 0, sizeof(ResultRelInfo));
 809         resultRelInfo->type = T_ResultRelInfo;
 810         resultRelInfo->ri_RangeTableIndex = resultRelationIndex;
 811         resultRelInfo->ri_RelationDesc = resultRelationDesc;
 812         resultRelInfo->ri_NumIndices = 0;
 813         resultRelInfo->ri_IndexRelationDescs = NULL;
 814         resultRelInfo->ri_IndexRelationInfo = NULL;
 815         /* make a copy so as not to depend on relcache info not changing... */
 816         resultRelInfo->ri_TrigDesc = CopyTriggerDesc(resultRelationDesc->trigdesc);
 817         resultRelInfo->ri_TrigFunctions = NULL;
 818         resultRelInfo->ri_ConstraintExprs = NULL;
 819         resultRelInfo->ri_junkFilter = NULL;
 820
 821         /*
 822          * If there are indices on the result relation, open them and save
 823          * descriptors in the result relation info, so that we can add new
 824          * index entries for the tuples we add/update.  We need not do this
 825          * for a DELETE, however, since deletion doesn't affect indexes.
 826          */
 827         if (resultRelationDesc->rd_rel->relhasindex &&
 828                 operation != CMD_DELETE)
 829                 ExecOpenIndices(resultRelInfo);
 830 }
 831
 832 /* ----------------------------------------------------------------
 833  *              ExecEndPlan
 834  *
 835  *              Cleans up the query plan -- closes files and frees up storage
 836  *
 837  * NOTE: we are no longer very worried about freeing storage per se
 838  * in this code; FreeExecutorState should be guaranteed to release all
 839  * memory that needs to be released.  What we are worried about doing
 840  * is closing relations and dropping buffer pins.  Thus, for example,
 841  * tuple tables must be cleared or dropped to ensure pins are released.
 842  * ----------------------------------------------------------------
 843  */
 844 void
 845 ExecEndPlan(PlanState *planstate, EState *estate)
 846 {
 847         ResultRelInfo *resultRelInfo;
 848         int                     i;
 849         List       *l;
 850
 851         /*
 852          * shut down any PlanQual processing we were doing
 853          */
 854         if (estate->es_evalPlanQual != NULL)
 855                 EndEvalPlanQual(estate);
 856
 857         /*
 858          * shut down the node-type-specific query processing
 859          */
 860         ExecEndNode(planstate);
 861
 862         /*
 863          * destroy the executor "tuple" table.
 864          */
 865         ExecDropTupleTable(estate->es_tupleTable, true);
 866         estate->es_tupleTable = NULL;
 867
 868         /*
 869          * close the result relation(s) if any, but hold locks until xact
 870          * commit.
 871          */
 872         resultRelInfo = estate->es_result_relations;
 873         for (i = estate->es_num_result_relations; i > 0; i--)
 874         {
 875                 /* Close indices and then the relation itself */
 876                 ExecCloseIndices(resultRelInfo);
 877                 heap_close(resultRelInfo->ri_RelationDesc, NoLock);
 878                 resultRelInfo++;
 879         }
 880
 881         /*
 882          * close the "into" relation if necessary, again keeping lock
 883          */
 884         if (estate->es_into_relation_descriptor != NULL)
 885                 heap_close(estate->es_into_relation_descriptor, NoLock);
 886
 887         /*
 888          * close any relations selected FOR UPDATE, again keeping locks
 889          */
 890         foreach(l, estate->es_rowMark)
 891         {
 892                 execRowMark *erm = lfirst(l);
 893
 894                 heap_close(erm->relation, NoLock);
 895         }
 896 }
 897
 898 /* ----------------------------------------------------------------
 899  *              ExecutePlan
 900  *
 901  *              processes the query plan to retrieve 'numberTuples' tuples in the
 902  *              direction specified.
 903  *
 904  *              Retrieves all tuples if numberTuples is 0
 905  *
 906  *              result is either a slot containing the last tuple in the case
 907  *              of a SELECT or NULL otherwise.
 908  *
 909  * Note: the ctid attribute is a 'junk' attribute that is removed before the
 910  * user can see it
 911  * ----------------------------------------------------------------
 912  */
 913 static TupleTableSlot *
 914 ExecutePlan(EState *estate,
 915                         PlanState *planstate,
 916                         CmdType operation,
 917                         long numberTuples,
 918                         ScanDirection direction,
 919                         DestReceiver *destfunc)
 920 {
 921         JunkFilter                      *junkfilter;
 922         TupleTableSlot          *slot;
 923         ItemPointer                      tupleid = NULL;
 924         ItemPointerData          tuple_ctid;
 925         long                             current_tuple_count;
 926         TupleTableSlot          *result;
 927
 928         /*
 929          * initialize local variables
 930          */
 931         slot = NULL;
 932         current_tuple_count = 0;
 933         result = NULL;
 934
 935         /*
 936          * Set the direction.
 937          */
 938         estate->es_direction = direction;
 939
 940         /*
 941          * Process BEFORE EACH STATEMENT triggers
 942          */
 943         switch (operation)
 944         {
 945                 case CMD_UPDATE:
 946                         ExecBSUpdateTriggers(estate, estate->es_result_relation_info);
 947                         break;
 948                 case CMD_DELETE:
 949                         ExecBSDeleteTriggers(estate, estate->es_result_relation_info);
 950                         break;
 951                 case CMD_INSERT:
 952                         ExecBSInsertTriggers(estate, estate->es_result_relation_info);
 953                         break;
 954                 default:
 955                         /* do nothing */
 956                         break;
 957         }
 958
 959         /*
 960          * Loop until we've processed the proper number of tuples from the
 961          * plan.
 962          */
 963
 964         for (;;)
 965         {
 966                 /* Reset the per-output-tuple exprcontext */
 967                 ResetPerTupleExprContext(estate);
 968
 969                 /*
 970                  * Execute the plan and obtain a tuple
 971                  */
 972 lnext:  ;
 973                 if (estate->es_useEvalPlan)
 974                 {
 975                         slot = EvalPlanQualNext(estate);
 976                         if (TupIsNull(slot))
 977                                 slot = ExecProcNode(planstate);
 978                 }
 979                 else
 980                         slot = ExecProcNode(planstate);
 981
 982                 /*
 983                  * if the tuple is null, then we assume there is nothing more to
 984                  * process so we just return null...
 985                  */
 986                 if (TupIsNull(slot))
 987                 {
 988                         result = NULL;
 989                         break;
 990                 }
 991
 992                 /*
 993                  * if we have a junk filter, then project a new tuple with the
 994                  * junk removed.
 995                  *
 996                  * Store this new "clean" tuple in the junkfilter's resultSlot.
 997                  * (Formerly, we stored it back over the "dirty" tuple, which is
 998                  * WRONG because that tuple slot has the wrong descriptor.)
 999                  *
1000                  * Also, extract all the junk information we need.
1001                  */
1002                 if ((junkfilter = estate->es_junkFilter) != (JunkFilter *) NULL)
1003                 {
1004                         Datum           datum;
1005                         HeapTuple       newTuple;
1006                         bool            isNull;
1007
1008                         /*
1009                          * extract the 'ctid' junk attribute.
1010                          */
1011                         if (operation == CMD_UPDATE || operation == CMD_DELETE)
1012                         {
1013                                 if (!ExecGetJunkAttribute(junkfilter,
1014                                                                                   slot,
1015                                                                                   "ctid",
1016                                                                                   &datum,
1017                                                                                   &isNull))
1018                                         elog(ERROR, "ExecutePlan: NO (junk) `ctid' was found!");
1019
1020                                 /* shouldn't ever get a null result... */
1021                                 if (isNull)
1022                                         elog(ERROR, "ExecutePlan: (junk) `ctid' is NULL!");
1023
1024                                 tupleid = (ItemPointer) DatumGetPointer(datum);
1025                                 tuple_ctid = *tupleid;  /* make sure we don't free the
1026                                                                                  * ctid!! */
1027                                 tupleid = &tuple_ctid;
1028                         }
1029                         else if (estate->es_rowMark != NIL)
1030                         {
1031                                 List       *l;
1032
1033                 lmark:  ;
1034                                 foreach(l, estate->es_rowMark)
1035                                 {
1036                                         execRowMark *erm = lfirst(l);
1037                                         Buffer          buffer;
1038                                         HeapTupleData tuple;
1039                                         TupleTableSlot *newSlot;
1040                                         int                     test;
1041
1042                                         if (!ExecGetJunkAttribute(junkfilter,
1043                                                                                           slot,
1044                                                                                           erm->resname,
1045                                                                                           &datum,
1046                                                                                           &isNull))
1047                                                 elog(ERROR, "ExecutePlan: NO (junk) `%s' was found!",
1048                                                          erm->resname);
1049
1050                                         /* shouldn't ever get a null result... */
1051                                         if (isNull)
1052                                                 elog(ERROR, "ExecutePlan: (junk) `%s' is NULL!",
1053                                                          erm->resname);
1054
1055                                         tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
1056                                         test = heap_mark4update(erm->relation, &tuple, &buffer,
1057                                                                                         estate->es_snapshot->curcid);
1058                                         ReleaseBuffer(buffer);
1059                                         switch (test)
1060                                         {
1061                                                 case HeapTupleSelfUpdated:
1062                                                         /* treat it as deleted; do not process */
1063                                                         goto lnext;
1064
1065                                                 case HeapTupleMayBeUpdated:
1066                                                         break;
1067
1068                                                 case HeapTupleUpdated:
1069                                                         if (XactIsoLevel == XACT_SERIALIZABLE)
1070                                                                 elog(ERROR, "Can't serialize access due to concurrent update");
1071                                                         if (!(ItemPointerEquals(&(tuple.t_self),
1072                                                                   (ItemPointer) DatumGetPointer(datum))))
1073                                                         {
1074                                                                 newSlot = EvalPlanQual(estate, erm->rti, &(tuple.t_self));
1075                                                                 if (!(TupIsNull(newSlot)))
1076                                                                 {
1077                                                                         slot = newSlot;
1078                                                                         estate->es_useEvalPlan = true;
1079                                                                         goto lmark;
1080                                                                 }
1081                                                         }
1082
1083                                                         /*
1084                                                          * if tuple was deleted or PlanQual failed for
1085                                                          * updated tuple - we must not return this
1086                                                          * tuple!
1087                                                          */
1088                                                         goto lnext;
1089
1090                                                 default:
1091                                                         elog(ERROR, "Unknown status %u from heap_mark4update", test);
1092                                                         return (NULL);
1093                                         }
1094                                 }
1095                         }
1096
1097                         /*
1098                          * Finally create a new "clean" tuple with all junk attributes
1099                          * removed
1100                          */
1101                         newTuple = ExecRemoveJunk(junkfilter, slot);
1102
1103                         slot = ExecStoreTuple(newTuple,         /* tuple to store */
1104                                                                   junkfilter->jf_resultSlot,    /* dest slot */
1105                                                                   InvalidBuffer,                /* this tuple has no
1106                                                                                                                  * buffer */
1107                                                                   true);                /* tuple should be pfreed */
1108                 }
1109
1110                 /*
1111                  * now that we have a tuple, do the appropriate thing with it..
1112                  * either return it to the user, add it to a relation someplace,
1113                  * delete it from a relation, or modify some of its attributes.
1114                  */
1115                 switch (operation)
1116                 {
1117                         case CMD_SELECT:
1118                                 ExecSelect(slot,        /* slot containing tuple */
1119                                                    destfunc,    /* destination's tuple-receiver
1120                                                                                  * obj */
1121                                                    estate);
1122                                 result = slot;
1123                                 break;
1124
1125                         case CMD_INSERT:
1126                                 ExecInsert(slot, tupleid, estate);
1127                                 result = NULL;
1128                                 break;
1129
1130                         case CMD_DELETE:
1131                                 ExecDelete(slot, tupleid, estate);
1132                                 result = NULL;
1133                                 break;
1134
1135                         case CMD_UPDATE:
1136                                 ExecUpdate(slot, tupleid, estate);
1137                                 result = NULL;
1138                                 break;
1139
1140                         default:
1141                                 elog(LOG, "ExecutePlan: unknown operation in queryDesc");
1142                                 result = NULL;
1143                                 break;
1144                 }
1145
1146                 /*
1147                  * check our tuple count.. if we've processed the proper number
1148                  * then quit, else loop again and process more tuples.  Zero
1149                  * numberTuples means no limit.
1150                  */
1151                 current_tuple_count++;
1152                 if (numberTuples && numberTuples == current_tuple_count)
1153                         break;
1154         }
1155
1156         /*
1157          * Process AFTER EACH STATEMENT triggers
1158          */
1159         switch (operation)
1160         {
1161                 case CMD_UPDATE:
1162                         ExecASUpdateTriggers(estate, estate->es_result_relation_info);
1163                         break;
1164                 case CMD_DELETE:
1165                         ExecASDeleteTriggers(estate, estate->es_result_relation_info);
1166                         break;
1167                 case CMD_INSERT:
1168                         ExecASInsertTriggers(estate, estate->es_result_relation_info);
1169                         break;
1170                 default:
1171                         /* do nothing */
1172                         break;
1173         }
1174
1175         /*
1176          * here, result is either a slot containing a tuple in the case of a
1177          * SELECT or NULL otherwise.
1178          */
1179         return result;
1180 }
1181
1182 /* ----------------------------------------------------------------
1183  *              ExecSelect
1184  *
1185  *              SELECTs are easy.. we just pass the tuple to the appropriate
1186  *              print function.  The only complexity is when we do a
1187  *              "SELECT INTO", in which case we insert the tuple into
1188  *              the appropriate relation (note: this is a newly created relation
1189  *              so we don't need to worry about indices or locks.)
1190  * ----------------------------------------------------------------
1191  */
1192 static void
1193 ExecSelect(TupleTableSlot *slot,
1194                    DestReceiver *destfunc,
1195                    EState *estate)
1196 {
1197         HeapTuple       tuple;
1198         TupleDesc       attrtype;
1199
1200         /*
1201          * get the heap tuple out of the tuple table slot
1202          */
1203         tuple = slot->val;
1204         attrtype = slot->ttc_tupleDescriptor;
1205
1206         /*
1207          * insert the tuple into the "into relation"
1208          */
1209         if (estate->es_into_relation_descriptor != NULL)
1210         {
1211                 heap_insert(estate->es_into_relation_descriptor, tuple,
1212                                         estate->es_snapshot->curcid);
1213                 IncrAppended();
1214         }
1215
1216         /*
1217          * send the tuple to the front end (or the screen)
1218          */
1219         (*destfunc->receiveTuple) (tuple, attrtype, destfunc);
1220         IncrRetrieved();
1221         (estate->es_processed)++;
1222 }
1223
1224 /* ----------------------------------------------------------------
1225  *              ExecInsert
1226  *
1227  *              INSERTs are trickier.. we have to insert the tuple into
1228  *              the base relation and insert appropriate tuples into the
1229  *              index relations.
1230  * ----------------------------------------------------------------
1231  */
1232 static void
1233 ExecInsert(TupleTableSlot *slot,
1234                    ItemPointer tupleid,
1235                    EState *estate)
1236 {
1237         HeapTuple       tuple;
1238         ResultRelInfo *resultRelInfo;
1239         Relation        resultRelationDesc;
1240         int                     numIndices;
1241         Oid                     newId;
1242
1243         /*
1244          * get the heap tuple out of the tuple table slot
1245          */
1246         tuple = slot->val;
1247
1248         /*
1249          * get information on the (current) result relation
1250          */
1251         resultRelInfo = estate->es_result_relation_info;
1252         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1253
1254         /* BEFORE ROW INSERT Triggers */
1255         if (resultRelInfo->ri_TrigDesc &&
1256                 resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_INSERT] > 0)
1257         {
1258                 HeapTuple       newtuple;
1259
1260                 newtuple = ExecBRInsertTriggers(estate, resultRelInfo, tuple);
1261
1262                 if (newtuple == NULL)   /* "do nothing" */
1263                         return;
1264
1265                 if (newtuple != tuple)  /* modified by Trigger(s) */
1266                 {
1267                         /*
1268                          * Insert modified tuple into tuple table slot, replacing the
1269                          * original.  We assume that it was allocated in per-tuple
1270                          * memory context, and therefore will go away by itself. The
1271                          * tuple table slot should not try to clear it.
1272                          */
1273                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1274                         tuple = newtuple;
1275                 }
1276         }
1277
1278         /*
1279          * Check the constraints of the tuple
1280          */
1281         if (resultRelationDesc->rd_att->constr)
1282                 ExecConstraints("ExecInsert", resultRelInfo, slot, estate);
1283
1284         /*
1285          * insert the tuple
1286          */
1287         newId = heap_insert(resultRelationDesc, tuple,
1288                                                 estate->es_snapshot->curcid);
1289
1290         IncrAppended();
1291         (estate->es_processed)++;
1292         estate->es_lastoid = newId;
1293         setLastTid(&(tuple->t_self));
1294
1295         /*
1296          * process indices
1297          *
1298          * Note: heap_insert adds a new tuple to a relation.  As a side effect,
1299          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1300          * field.
1301          */
1302         numIndices = resultRelInfo->ri_NumIndices;
1303         if (numIndices > 0)
1304                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1305
1306         /* AFTER ROW INSERT Triggers */
1307         ExecARInsertTriggers(estate, resultRelInfo, tuple);
1308 }
1309
1310 /* ----------------------------------------------------------------
1311  *              ExecDelete
1312  *
1313  *              DELETE is like UPDATE, we delete the tuple and its
1314  *              index tuples.
1315  * ----------------------------------------------------------------
1316  */
1317 static void
1318 ExecDelete(TupleTableSlot *slot,
1319                    ItemPointer tupleid,
1320                    EState *estate)
1321 {
1322         ResultRelInfo *resultRelInfo;
1323         Relation        resultRelationDesc;
1324         ItemPointerData ctid;
1325         int                     result;
1326
1327         /*
1328          * get information on the (current) result relation
1329          */
1330         resultRelInfo = estate->es_result_relation_info;
1331         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1332
1333         /* BEFORE ROW DELETE Triggers */
1334         if (resultRelInfo->ri_TrigDesc &&
1335           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_DELETE] > 0)
1336         {
1337                 bool            dodelete;
1338
1339                 dodelete = ExecBRDeleteTriggers(estate, resultRelInfo, tupleid);
1340
1341                 if (!dodelete)                  /* "do nothing" */
1342                         return;
1343         }
1344
1345         /*
1346          * delete the tuple
1347          */
1348 ldelete:;
1349         result = heap_delete(resultRelationDesc, tupleid,
1350                                                  &ctid,
1351                                                  estate->es_snapshot->curcid);
1352         switch (result)
1353         {
1354                 case HeapTupleSelfUpdated:
1355                         /* already deleted by self; nothing to do */
1356                         return;
1357
1358                 case HeapTupleMayBeUpdated:
1359                         break;
1360
1361                 case HeapTupleUpdated:
1362                         if (XactIsoLevel == XACT_SERIALIZABLE)
1363                                 elog(ERROR, "Can't serialize access due to concurrent update");
1364                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1365                         {
1366                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1367                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1368
1369                                 if (!TupIsNull(epqslot))
1370                                 {
1371                                         *tupleid = ctid;
1372                                         goto ldelete;
1373                                 }
1374                         }
1375                         /* tuple already deleted; nothing to do */
1376                         return;
1377
1378                 default:
1379                         elog(ERROR, "Unknown status %u from heap_delete", result);
1380                         return;
1381         }
1382
1383         IncrDeleted();
1384         (estate->es_processed)++;
1385
1386         /*
1387          * Note: Normally one would think that we have to delete index tuples
1388          * associated with the heap tuple now..
1389          *
1390          * ... but in POSTGRES, we have no need to do this because the vacuum
1391          * daemon automatically opens an index scan and deletes index tuples
1392          * when it finds deleted heap tuples. -cim 9/27/89
1393          */
1394
1395         /* AFTER ROW DELETE Triggers */
1396         ExecARDeleteTriggers(estate, resultRelInfo, tupleid);
1397 }
1398
1399 /* ----------------------------------------------------------------
1400  *              ExecUpdate
1401  *
1402  *              note: we can't run UPDATE queries with transactions
1403  *              off because UPDATEs are actually INSERTs and our
1404  *              scan will mistakenly loop forever, updating the tuple
1405  *              it just inserted..      This should be fixed but until it
1406  *              is, we don't want to get stuck in an infinite loop
1407  *              which corrupts your database..
1408  * ----------------------------------------------------------------
1409  */
1410 static void
1411 ExecUpdate(TupleTableSlot *slot,
1412                    ItemPointer tupleid,
1413                    EState *estate)
1414 {
1415         HeapTuple       tuple;
1416         ResultRelInfo *resultRelInfo;
1417         Relation        resultRelationDesc;
1418         ItemPointerData ctid;
1419         int                     result;
1420         int                     numIndices;
1421
1422         /*
1423          * abort the operation if not running transactions
1424          */
1425         if (IsBootstrapProcessingMode())
1426         {
1427                 elog(WARNING, "ExecUpdate: UPDATE can't run without transactions");
1428                 return;
1429         }
1430
1431         /*
1432          * get the heap tuple out of the tuple table slot
1433          */
1434         tuple = slot->val;
1435
1436         /*
1437          * get information on the (current) result relation
1438          */
1439         resultRelInfo = estate->es_result_relation_info;
1440         resultRelationDesc = resultRelInfo->ri_RelationDesc;
1441
1442         /* BEFORE ROW UPDATE Triggers */
1443         if (resultRelInfo->ri_TrigDesc &&
1444           resultRelInfo->ri_TrigDesc->n_before_row[TRIGGER_EVENT_UPDATE] > 0)
1445         {
1446                 HeapTuple       newtuple;
1447
1448                 newtuple = ExecBRUpdateTriggers(estate, resultRelInfo,
1449                                                                                 tupleid, tuple);
1450
1451                 if (newtuple == NULL)   /* "do nothing" */
1452                         return;
1453
1454                 if (newtuple != tuple)  /* modified by Trigger(s) */
1455                 {
1456                         /*
1457                          * Insert modified tuple into tuple table slot, replacing the
1458                          * original.  We assume that it was allocated in per-tuple
1459                          * memory context, and therefore will go away by itself. The
1460                          * tuple table slot should not try to clear it.
1461                          */
1462                         ExecStoreTuple(newtuple, slot, InvalidBuffer, false);
1463                         tuple = newtuple;
1464                 }
1465         }
1466
1467         /*
1468          * Check the constraints of the tuple
1469          *
1470          * If we generate a new candidate tuple after EvalPlanQual testing, we
1471          * must loop back here and recheck constraints.  (We don't need to
1472          * redo triggers, however.      If there are any BEFORE triggers then
1473          * trigger.c will have done mark4update to lock the correct tuple, so
1474          * there's no need to do them again.)
1475          */
1476 lreplace:;
1477         if (resultRelationDesc->rd_att->constr)
1478                 ExecConstraints("ExecUpdate", resultRelInfo, slot, estate);
1479
1480         /*
1481          * replace the heap tuple
1482          */
1483         result = heap_update(resultRelationDesc, tupleid, tuple,
1484                                                  &ctid,
1485                                                  estate->es_snapshot->curcid);
1486         switch (result)
1487         {
1488                 case HeapTupleSelfUpdated:
1489                         /* already deleted by self; nothing to do */
1490                         return;
1491
1492                 case HeapTupleMayBeUpdated:
1493                         break;
1494
1495                 case HeapTupleUpdated:
1496                         if (XactIsoLevel == XACT_SERIALIZABLE)
1497                                 elog(ERROR, "Can't serialize access due to concurrent update");
1498                         else if (!(ItemPointerEquals(tupleid, &ctid)))
1499                         {
1500                                 TupleTableSlot *epqslot = EvalPlanQual(estate,
1501                                                            resultRelInfo->ri_RangeTableIndex, &ctid);
1502
1503                                 if (!TupIsNull(epqslot))
1504                                 {
1505                                         *tupleid = ctid;
1506                                         tuple = ExecRemoveJunk(estate->es_junkFilter, epqslot);
1507                                         slot = ExecStoreTuple(tuple,
1508                                                                         estate->es_junkFilter->jf_resultSlot,
1509                                                                                   InvalidBuffer, true);
1510                                         goto lreplace;
1511                                 }
1512                         }
1513                         /* tuple already deleted; nothing to do */
1514                         return;
1515
1516                 default:
1517                         elog(ERROR, "Unknown status %u from heap_update", result);
1518                         return;
1519         }
1520
1521         IncrReplaced();
1522         (estate->es_processed)++;
1523
1524         /*
1525          * Note: instead of having to update the old index tuples associated
1526          * with the heap tuple, all we do is form and insert new index tuples.
1527          * This is because UPDATEs are actually DELETEs and INSERTs and index
1528          * tuple deletion is done automagically by the vacuum daemon. All we
1529          * do is insert new index tuples.  -cim 9/27/89
1530          */
1531
1532         /*
1533          * process indices
1534          *
1535          * heap_update updates a tuple in the base relation by invalidating it
1536          * and then inserting a new tuple to the relation.      As a side effect,
1537          * the tupleid of the new tuple is placed in the new tuple's t_ctid
1538          * field.  So we now insert index tuples using the new tupleid stored
1539          * there.
1540          */
1541
1542         numIndices = resultRelInfo->ri_NumIndices;
1543         if (numIndices > 0)
1544                 ExecInsertIndexTuples(slot, &(tuple->t_self), estate, false);
1545
1546         /* AFTER ROW UPDATE Triggers */
1547         ExecARUpdateTriggers(estate, resultRelInfo, tupleid, tuple);
1548 }
1549
1550 static char *
1551 ExecRelCheck(ResultRelInfo *resultRelInfo,
1552                          TupleTableSlot *slot, EState *estate)
1553 {
1554         Relation        rel = resultRelInfo->ri_RelationDesc;
1555         int                     ncheck = rel->rd_att->constr->num_check;
1556         ConstrCheck *check = rel->rd_att->constr->check;
1557         ExprContext *econtext;
1558         MemoryContext oldContext;
1559         List       *qual;
1560         int                     i;
1561
1562         /*
1563          * If first time through for this result relation, build expression
1564          * nodetrees for rel's constraint expressions.  Keep them in the
1565          * per-query memory context so they'll survive throughout the query.
1566          */
1567         if (resultRelInfo->ri_ConstraintExprs == NULL)
1568         {
1569                 oldContext = MemoryContextSwitchTo(estate->es_query_cxt);
1570                 resultRelInfo->ri_ConstraintExprs =
1571                         (List **) palloc(ncheck * sizeof(List *));
1572                 for (i = 0; i < ncheck; i++)
1573                 {
1574                         qual = (List *) stringToNode(check[i].ccbin);
1575                         resultRelInfo->ri_ConstraintExprs[i] = (List *)
1576                                 ExecPrepareExpr((Expr *) qual, estate);
1577                 }
1578                 MemoryContextSwitchTo(oldContext);
1579         }
1580
1581         /*
1582          * We will use the EState's per-tuple context for evaluating
1583          * constraint expressions (creating it if it's not already there).
1584          */
1585         econtext = GetPerTupleExprContext(estate);
1586
1587         /* Arrange for econtext's scan tuple to be the tuple under test */
1588         econtext->ecxt_scantuple = slot;
1589
1590         /* And evaluate the constraints */
1591         for (i = 0; i < ncheck; i++)
1592         {
1593                 qual = resultRelInfo->ri_ConstraintExprs[i];
1594
1595                 /*
1596                  * NOTE: SQL92 specifies that a NULL result from a constraint
1597                  * expression is not to be treated as a failure.  Therefore, tell
1598                  * ExecQual to return TRUE for NULL.
1599                  */
1600                 if (!ExecQual(qual, econtext, true))
1601                         return check[i].ccname;
1602         }
1603
1604         /* NULL result means no error */
1605         return (char *) NULL;
1606 }
1607
1608 void
1609 ExecConstraints(const char *caller, ResultRelInfo *resultRelInfo,
1610                                 TupleTableSlot *slot, EState *estate)
1611 {
1612         Relation        rel = resultRelInfo->ri_RelationDesc;
1613         HeapTuple       tuple = slot->val;
1614         TupleConstr *constr = rel->rd_att->constr;
1615
1616         Assert(constr);
1617
1618         if (constr->has_not_null)
1619         {
1620                 int                     natts = rel->rd_att->natts;
1621                 int                     attrChk;
1622
1623                 for (attrChk = 1; attrChk <= natts; attrChk++)
1624                 {
1625                         if (rel->rd_att->attrs[attrChk - 1]->attnotnull &&
1626                                 heap_attisnull(tuple, attrChk))
1627                                 elog(ERROR, "%s: Fail to add null value in not null attribute %s",
1628                                          caller, NameStr(rel->rd_att->attrs[attrChk - 1]->attname));
1629                 }
1630         }
1631
1632         if (constr->num_check > 0)
1633         {
1634                 char       *failed;
1635
1636                 if ((failed = ExecRelCheck(resultRelInfo, slot, estate)) != NULL)
1637                         elog(ERROR, "%s: rejected due to CHECK constraint \"%s\" on \"%s\"",
1638                                  caller, failed, RelationGetRelationName(rel));
1639         }
1640 }
1641
1642 /*
1643  * Check a modified tuple to see if we want to process its updated version
1644  * under READ COMMITTED rules.
1645  *
1646  * See backend/executor/README for some info about how this works.
1647  */
1648 TupleTableSlot *
1649 EvalPlanQual(EState *estate, Index rti, ItemPointer tid)
1650 {
1651         evalPlanQual *epq;
1652         EState     *epqstate;
1653         Relation        relation;
1654         HeapTupleData tuple;
1655         HeapTuple       copyTuple = NULL;
1656         bool            endNode;
1657
1658         Assert(rti != 0);
1659
1660         /*
1661          * find relation containing target tuple
1662          */
1663         if (estate->es_result_relation_info != NULL &&
1664                 estate->es_result_relation_info->ri_RangeTableIndex == rti)
1665                 relation = estate->es_result_relation_info->ri_RelationDesc;
1666         else
1667         {
1668                 List       *l;
1669
1670                 relation = NULL;
1671                 foreach(l, estate->es_rowMark)
1672                 {
1673                         if (((execRowMark *) lfirst(l))->rti == rti)
1674                         {
1675                                 relation = ((execRowMark *) lfirst(l))->relation;
1676                                 break;
1677                         }
1678                 }
1679                 if (relation == NULL)
1680                         elog(ERROR, "EvalPlanQual: can't find RTE %d", (int) rti);
1681         }
1682
1683         /*
1684          * fetch tid tuple
1685          *
1686          * Loop here to deal with updated or busy tuples
1687          */
1688         tuple.t_self = *tid;
1689         for (;;)
1690         {
1691                 Buffer          buffer;
1692
1693                 if (heap_fetch(relation, SnapshotDirty, &tuple, &buffer, false, NULL))
1694                 {
1695                         TransactionId xwait = SnapshotDirty->xmax;
1696
1697                         if (TransactionIdIsValid(SnapshotDirty->xmin))
1698                                 elog(ERROR, "EvalPlanQual: t_xmin is uncommitted ?!");
1699
1700                         /*
1701                          * If tuple is being updated by other transaction then we have
1702                          * to wait for its commit/abort.
1703                          */
1704                         if (TransactionIdIsValid(xwait))
1705                         {
1706                                 ReleaseBuffer(buffer);
1707                                 XactLockTableWait(xwait);
1708                                 continue;
1709                         }
1710
1711                         /*
1712                          * We got tuple - now copy it for use by recheck query.
1713                          */
1714                         copyTuple = heap_copytuple(&tuple);
1715                         ReleaseBuffer(buffer);
1716                         break;
1717                 }
1718
1719                 /*
1720                  * Oops! Invalid tuple. Have to check is it updated or deleted.
1721                  * Note that it's possible to get invalid SnapshotDirty->tid if
1722                  * tuple updated by this transaction. Have we to check this ?
1723                  */
1724                 if (ItemPointerIsValid(&(SnapshotDirty->tid)) &&
1725                         !(ItemPointerEquals(&(tuple.t_self), &(SnapshotDirty->tid))))
1726                 {
1727                         /* updated, so look at the updated copy */
1728                         tuple.t_self = SnapshotDirty->tid;
1729                         continue;
1730                 }
1731
1732                 /*
1733                  * Deleted or updated by this transaction; forget it.
1734                  */
1735                 return NULL;
1736         }
1737
1738         /*
1739          * For UPDATE/DELETE we have to return tid of actual row we're
1740          * executing PQ for.
1741          */
1742         *tid = tuple.t_self;
1743
1744         /*
1745          * Need to run a recheck subquery.      Find or create a PQ stack entry.
1746          */
1747         epq = estate->es_evalPlanQual;
1748         endNode = true;
1749
1750         if (epq != NULL && epq->rti == 0)
1751         {
1752                 /* Top PQ stack entry is idle, so re-use it */
1753                 Assert(!(estate->es_useEvalPlan) && epq->next == NULL);
1754                 epq->rti = rti;
1755                 endNode = false;
1756         }
1757
1758         /*
1759          * If this is request for another RTE - Ra, - then we have to check
1760          * wasn't PlanQual requested for Ra already and if so then Ra' row was
1761          * updated again and we have to re-start old execution for Ra and
1762          * forget all what we done after Ra was suspended. Cool? -:))
1763          */
1764         if (epq != NULL && epq->rti != rti &&
1765                 epq->estate->es_evTuple[rti - 1] != NULL)
1766         {
1767                 do
1768                 {
1769                         evalPlanQual *oldepq;
1770
1771                         /* stop execution */
1772                         EvalPlanQualStop(epq);
1773                         /* pop previous PlanQual from the stack */
1774                         oldepq = epq->next;
1775                         Assert(oldepq && oldepq->rti != 0);
1776                         /* push current PQ to freePQ stack */
1777                         oldepq->free = epq;
1778                         epq = oldepq;
1779                         estate->es_evalPlanQual = epq;
1780                 } while (epq->rti != rti);
1781         }
1782
1783         /*
1784          * If we are requested for another RTE then we have to suspend
1785          * execution of current PlanQual and start execution for new one.
1786          */
1787         if (epq == NULL || epq->rti != rti)
1788         {
1789                 /* try to reuse plan used previously */
1790                 evalPlanQual *newepq = (epq != NULL) ? epq->free : NULL;
1791
1792                 if (newepq == NULL)             /* first call or freePQ stack is empty */
1793                 {
1794                         newepq = (evalPlanQual *) palloc0(sizeof(evalPlanQual));
1795                         newepq->free = NULL;
1796                         newepq->estate = NULL;
1797                         newepq->planstate = NULL;
1798                 }
1799                 else
1800                 {
1801                         /* recycle previously used PlanQual */
1802                         Assert(newepq->estate == NULL);
1803                         epq->free = NULL;
1804                 }
1805                 /* push current PQ to the stack */
1806                 newepq->next = epq;
1807                 epq = newepq;
1808                 estate->es_evalPlanQual = epq;
1809                 epq->rti = rti;
1810                 endNode = false;
1811         }
1812
1813         Assert(epq->rti == rti);
1814
1815         /*
1816          * Ok - we're requested for the same RTE.  Unfortunately we still have
1817          * to end and restart execution of the plan, because ExecReScan
1818          * wouldn't ensure that upper plan nodes would reset themselves.  We
1819          * could make that work if insertion of the target tuple were
1820          * integrated with the Param mechanism somehow, so that the upper plan
1821          * nodes know that their children's outputs have changed.
1822          *
1823          * Note that the stack of free evalPlanQual nodes is quite useless at
1824          * the moment, since it only saves us from pallocing/releasing the
1825          * evalPlanQual nodes themselves.  But it will be useful once we
1826          * implement ReScan instead of end/restart for re-using PlanQual nodes.
1827          */
1828         if (endNode)
1829         {
1830                 /* stop execution */
1831                 EvalPlanQualStop(epq);
1832         }
1833
1834         /*
1835          * Initialize new recheck query.
1836          *
1837          * Note: if we were re-using PlanQual plans via ExecReScan, we'd need
1838          * to instead copy down changeable state from the top plan (including
1839          * es_result_relation_info, es_junkFilter) and reset locally changeable
1840          * state in the epq (including es_param_exec_vals, es_evTupleNull).
1841          */
1842         EvalPlanQualStart(epq, estate, epq->next);
1843
1844         /*
1845          * free old RTE' tuple, if any, and store target tuple where
1846          * relation's scan node will see it
1847          */
1848         epqstate = epq->estate;
1849         if (epqstate->es_evTuple[rti - 1] != NULL)
1850                 heap_freetuple(epqstate->es_evTuple[rti - 1]);
1851         epqstate->es_evTuple[rti - 1] = copyTuple;
1852
1853         return EvalPlanQualNext(estate);
1854 }
1855
1856 static TupleTableSlot *
1857 EvalPlanQualNext(EState *estate)
1858 {
1859         evalPlanQual *epq = estate->es_evalPlanQual;
1860         MemoryContext oldcontext;
1861         TupleTableSlot *slot;
1862
1863         Assert(epq->rti != 0);
1864
1865 lpqnext:;
1866         oldcontext = MemoryContextSwitchTo(epq->estate->es_query_cxt);
1867         slot = ExecProcNode(epq->planstate);
1868         MemoryContextSwitchTo(oldcontext);
1869
1870         /*
1871          * No more tuples for this PQ. Continue previous one.
1872          */
1873         if (TupIsNull(slot))
1874         {
1875                 evalPlanQual *oldepq;
1876
1877                 /* stop execution */
1878                 EvalPlanQualStop(epq);
1879                 /* pop old PQ from the stack */
1880                 oldepq = epq->next;
1881                 if (oldepq == NULL)
1882                 {
1883                         /* this is the first (oldest) PQ - mark as free */
1884                         epq->rti = 0;
1885                         estate->es_useEvalPlan = false;
1886                         /* and continue Query execution */
1887                         return (NULL);
1888                 }
1889                 Assert(oldepq->rti != 0);
1890                 /* push current PQ to freePQ stack */
1891                 oldepq->free = epq;
1892                 epq = oldepq;
1893                 estate->es_evalPlanQual = epq;
1894                 goto lpqnext;
1895         }
1896
1897         return (slot);
1898 }
1899
1900 static void
1901 EndEvalPlanQual(EState *estate)
1902 {
1903         evalPlanQual *epq = estate->es_evalPlanQual;
1904
1905         if (epq->rti == 0)                      /* plans already shutdowned */
1906         {
1907                 Assert(epq->next == NULL);
1908                 return;
1909         }
1910
1911         for (;;)
1912         {
1913                 evalPlanQual *oldepq;
1914
1915                 /* stop execution */
1916                 EvalPlanQualStop(epq);
1917                 /* pop old PQ from the stack */
1918                 oldepq = epq->next;
1919                 if (oldepq == NULL)
1920                 {
1921                         /* this is the first (oldest) PQ - mark as free */
1922                         epq->rti = 0;
1923                         estate->es_useEvalPlan = false;
1924                         break;
1925                 }
1926                 Assert(oldepq->rti != 0);
1927                 /* push current PQ to freePQ stack */
1928                 oldepq->free = epq;
1929                 epq = oldepq;
1930                 estate->es_evalPlanQual = epq;
1931         }
1932 }
1933
1934 /*
1935  * Start execution of one level of PlanQual.
1936  *
1937  * This is a cut-down version of ExecutorStart(): we copy some state from
1938  * the top-level estate rather than initializing it fresh.
1939  */
1940 static void
1941 EvalPlanQualStart(evalPlanQual *epq, EState *estate, evalPlanQual *priorepq)
1942 {
1943         EState     *epqstate;
1944         int                     rtsize;
1945         MemoryContext oldcontext;
1946
1947         rtsize = length(estate->es_range_table);
1948
1949         epq->estate = epqstate = CreateExecutorState();
1950
1951         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
1952
1953         /*
1954          * The epqstates share the top query's copy of unchanging state such
1955          * as the snapshot, rangetable, result-rel info, and external Param info.
1956          * They need their own copies of local state, including a tuple table,
1957          * es_param_exec_vals, etc.
1958          */
1959         epqstate->es_direction = ForwardScanDirection;
1960         epqstate->es_snapshot = estate->es_snapshot;
1961         epqstate->es_range_table = estate->es_range_table;
1962         epqstate->es_result_relations = estate->es_result_relations;
1963         epqstate->es_num_result_relations = estate->es_num_result_relations;
1964         epqstate->es_result_relation_info = estate->es_result_relation_info;
1965         epqstate->es_junkFilter = estate->es_junkFilter;
1966         epqstate->es_into_relation_descriptor = estate->es_into_relation_descriptor;
1967         epqstate->es_param_list_info = estate->es_param_list_info;
1968         if (estate->es_topPlan->nParamExec > 0)
1969                 epqstate->es_param_exec_vals = (ParamExecData *)
1970                         palloc0(estate->es_topPlan->nParamExec * sizeof(ParamExecData));
1971         epqstate->es_rowMark = estate->es_rowMark;
1972         epqstate->es_instrument = estate->es_instrument;
1973         epqstate->es_force_oids = estate->es_force_oids;
1974         epqstate->es_topPlan = estate->es_topPlan;
1975         /*
1976          * Each epqstate must have its own es_evTupleNull state, but
1977          * all the stack entries share es_evTuple state.  This allows
1978          * sub-rechecks to inherit the value being examined by an
1979          * outer recheck.
1980          */
1981         epqstate->es_evTupleNull = (bool *) palloc0(rtsize * sizeof(bool));
1982         if (priorepq == NULL)
1983                 /* first PQ stack entry */
1984                 epqstate->es_evTuple = (HeapTuple *)
1985                         palloc0(rtsize * sizeof(HeapTuple));
1986         else
1987                 /* later stack entries share the same storage */
1988                 epqstate->es_evTuple = priorepq->estate->es_evTuple;
1989
1990         epqstate->es_tupleTable =
1991                 ExecCreateTupleTable(estate->es_tupleTable->size);
1992
1993         epq->planstate = ExecInitNode(estate->es_topPlan, epqstate);
1994
1995         MemoryContextSwitchTo(oldcontext);
1996 }
1997
1998 /*
1999  * End execution of one level of PlanQual.
2000  *
2001  * This is a cut-down version of ExecutorEnd(); basically we want to do most
2002  * of the normal cleanup, but *not* close result relations (which we are
2003  * just sharing from the outer query).
2004  */
2005 static void
2006 EvalPlanQualStop(evalPlanQual *epq)
2007 {
2008         EState     *epqstate = epq->estate;
2009         MemoryContext oldcontext;
2010
2011         oldcontext = MemoryContextSwitchTo(epqstate->es_query_cxt);
2012
2013         ExecEndNode(epq->planstate);
2014
2015         ExecDropTupleTable(epqstate->es_tupleTable, true);
2016         epqstate->es_tupleTable = NULL;
2017
2018         if (epqstate->es_evTuple[epq->rti - 1] != NULL)
2019         {
2020                 heap_freetuple(epqstate->es_evTuple[epq->rti - 1]);
2021                 epqstate->es_evTuple[epq->rti - 1] = NULL;
2022         }
2023
2024         MemoryContextSwitchTo(oldcontext);
2025
2026         FreeExecutorState(epqstate);
2027
2028         epq->estate = NULL;
2029         epq->planstate = NULL;
2030 }