granicus.if.org Git - postgresql/blob - src/backend/access/index/indexam.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * indexam.c
   4  *        general index access method routines
   5  *
   6  * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/backend/access/index/indexam.c
  12  *
  13  * INTERFACE ROUTINES
  14  *              index_open              - open an index relation by relation OID
  15  *              index_close             - close an index relation
  16  *              index_beginscan - start a scan of an index with amgettuple
  17  *              index_beginscan_bitmap - start a scan of an index with amgetbitmap
  18  *              index_rescan    - restart a scan of an index
  19  *              index_endscan   - end a scan
  20  *              index_insert    - insert an index tuple into a relation
  21  *              index_markpos   - mark a scan position
  22  *              index_restrpos  - restore a scan position
  23  *              index_getnext_tid       - get the next TID from a scan
  24  *              index_fetch_heap                - get the scan's next heap tuple
  25  *              index_getnext   - get the next heap tuple from a scan
  26  *              index_getbitmap - get all tuples from a scan
  27  *              index_bulk_delete       - bulk deletion of index tuples
  28  *              index_vacuum_cleanup    - post-deletion cleanup of an index
  29  *              index_can_return        - does index support index-only scans?
  30  *              index_getprocid - get a support procedure OID
  31  *              index_getprocinfo - get a support procedure's lookup info
  32  *
  33  * NOTES
  34  *              This file contains the index_ routines which used
  35  *              to be a scattered collection of stuff in access/genam.
  36  *
  37  *
  38  * old comments
  39  *              Scans are implemented as follows:
  40  *
  41  *              `0' represents an invalid item pointer.
  42  *              `-' represents an unknown item pointer.
  43  *              `X' represents a known item pointers.
  44  *              `+' represents known or invalid item pointers.
  45  *              `*' represents any item pointers.
  46  *
  47  *              State is represented by a triple of these symbols in the order of
  48  *              previous, current, next.  Note that the case of reverse scans works
  49  *              identically.
  50  *
  51  *                              State   Result
  52  *              (1)             + + -   + 0 0                   (if the next item pointer is invalid)
  53  *              (2)                             + X -                   (otherwise)
  54  *              (3)             * 0 0   * 0 0                   (no change)
  55  *              (4)             + X 0   X 0 0                   (shift)
  56  *              (5)             * + X   + X -                   (shift, add unknown)
  57  *
  58  *              All other states cannot occur.
  59  *
  60  *              Note: It would be possible to cache the status of the previous and
  61  *                        next item pointer using the flags.
  62  *
  63  *-------------------------------------------------------------------------
  64  */
  65
  66 #include "postgres.h"
  67
  68 #include "access/relscan.h"
  69 #include "access/transam.h"
  70 #include "access/xlog.h"
  71
  72 #include "catalog/index.h"
  73 #include "catalog/catalog.h"
  74 #include "pgstat.h"
  75 #include "storage/bufmgr.h"
  76 #include "storage/lmgr.h"
  77 #include "storage/predicate.h"
  78 #include "utils/snapmgr.h"
  79 #include "utils/tqual.h"
  80
  81
  82 /* ----------------------------------------------------------------
  83  *                                      macros used in index_ routines
  84  *
  85  * Note: the ReindexIsProcessingIndex() check in RELATION_CHECKS is there
  86  * to check that we don't try to scan or do retail insertions into an index
  87  * that is currently being rebuilt or pending rebuild.  This helps to catch
  88  * things that don't work when reindexing system catalogs.  The assertion
  89  * doesn't prevent the actual rebuild because we don't use RELATION_CHECKS
  90  * when calling the index AM's ambuild routine, and there is no reason for
  91  * ambuild to call its subsidiary routines through this file.
  92  * ----------------------------------------------------------------
  93  */
  94 #define RELATION_CHECKS \
  95 ( \
  96         AssertMacro(RelationIsValid(indexRelation)), \
  97         AssertMacro(PointerIsValid(indexRelation->rd_am)), \
  98         AssertMacro(!ReindexIsProcessingIndex(RelationGetRelid(indexRelation))) \
  99 )
 100
 101 #define SCAN_CHECKS \
 102 ( \
 103         AssertMacro(IndexScanIsValid(scan)), \
 104         AssertMacro(RelationIsValid(scan->indexRelation)), \
 105         AssertMacro(PointerIsValid(scan->indexRelation->rd_am)) \
 106 )
 107
 108 #define GET_REL_PROCEDURE(pname) \
 109 do { \
 110         procedure = &indexRelation->rd_aminfo->pname; \
 111         if (!OidIsValid(procedure->fn_oid)) \
 112         { \
 113                 RegProcedure    procOid = indexRelation->rd_am->pname; \
 114                 if (!RegProcedureIsValid(procOid)) \
 115                         elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
 116                 fmgr_info_cxt(procOid, procedure, indexRelation->rd_indexcxt); \
 117         } \
 118 } while(0)
 119
 120 #define GET_UNCACHED_REL_PROCEDURE(pname) \
 121 do { \
 122         if (!RegProcedureIsValid(indexRelation->rd_am->pname)) \
 123                 elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
 124         fmgr_info(indexRelation->rd_am->pname, &procedure); \
 125 } while(0)
 126
 127 #define GET_SCAN_PROCEDURE(pname) \
 128 do { \
 129         procedure = &scan->indexRelation->rd_aminfo->pname; \
 130         if (!OidIsValid(procedure->fn_oid)) \
 131         { \
 132                 RegProcedure    procOid = scan->indexRelation->rd_am->pname; \
 133                 if (!RegProcedureIsValid(procOid)) \
 134                         elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
 135                 fmgr_info_cxt(procOid, procedure, scan->indexRelation->rd_indexcxt); \
 136         } \
 137 } while(0)
 138
 139 static IndexScanDesc index_beginscan_internal(Relation indexRelation,
 140                                                  int nkeys, int norderbys, Snapshot snapshot);
 141
 142
 143 /* ----------------------------------------------------------------
 144  *                                 index_ interface functions
 145  * ----------------------------------------------------------------
 146  */
 147
 148 /* ----------------
 149  *              index_open - open an index relation by relation OID
 150  *
 151  *              If lockmode is not "NoLock", the specified kind of lock is
 152  *              obtained on the index.  (Generally, NoLock should only be
 153  *              used if the caller knows it has some appropriate lock on the
 154  *              index already.)
 155  *
 156  *              An error is raised if the index does not exist.
 157  *
 158  *              This is a convenience routine adapted for indexscan use.
 159  *              Some callers may prefer to use relation_open directly.
 160  * ----------------
 161  */
 162 Relation
 163 index_open(Oid relationId, LOCKMODE lockmode)
 164 {
 165         Relation        r;
 166
 167         r = relation_open(relationId, lockmode);
 168
 169         if (r->rd_rel->relkind != RELKIND_INDEX)
 170                 ereport(ERROR,
 171                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 172                                  errmsg("\"%s\" is not an index",
 173                                                 RelationGetRelationName(r))));
 174
 175         return r;
 176 }
 177
 178 /* ----------------
 179  *              index_close - close an index relation
 180  *
 181  *              If lockmode is not "NoLock", we then release the specified lock.
 182  *
 183  *              Note that it is often sensible to hold a lock beyond index_close;
 184  *              in that case, the lock is released automatically at xact end.
 185  * ----------------
 186  */
 187 void
 188 index_close(Relation relation, LOCKMODE lockmode)
 189 {
 190         LockRelId       relid = relation->rd_lockInfo.lockRelId;
 191
 192         Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
 193
 194         /* The relcache does the real work... */
 195         RelationClose(relation);
 196
 197         if (lockmode != NoLock)
 198                 UnlockRelationId(&relid, lockmode);
 199 }
 200
 201 /* ----------------
 202  *              index_insert - insert an index tuple into a relation
 203  * ----------------
 204  */
 205 bool
 206 index_insert(Relation indexRelation,
 207                          Datum *values,
 208                          bool *isnull,
 209                          ItemPointer heap_t_ctid,
 210                          Relation heapRelation,
 211                          IndexUniqueCheck checkUnique)
 212 {
 213         FmgrInfo   *procedure;
 214
 215         RELATION_CHECKS;
 216         GET_REL_PROCEDURE(aminsert);
 217
 218         if (!(indexRelation->rd_am->ampredlocks))
 219                 CheckForSerializableConflictIn(indexRelation,
 220                                                                            (HeapTuple) NULL,
 221                                                                            InvalidBuffer);
 222
 223         /*
 224          * have the am's insert proc do all the work.
 225          */
 226         return DatumGetBool(FunctionCall6(procedure,
 227                                                                           PointerGetDatum(indexRelation),
 228                                                                           PointerGetDatum(values),
 229                                                                           PointerGetDatum(isnull),
 230                                                                           PointerGetDatum(heap_t_ctid),
 231                                                                           PointerGetDatum(heapRelation),
 232                                                                           Int32GetDatum((int32) checkUnique)));
 233 }
 234
 235 /*
 236  * index_beginscan - start a scan of an index with amgettuple
 237  *
 238  * Caller must be holding suitable locks on the heap and the index.
 239  */
 240 IndexScanDesc
 241 index_beginscan(Relation heapRelation,
 242                                 Relation indexRelation,
 243                                 Snapshot snapshot,
 244                                 int nkeys, int norderbys)
 245 {
 246         IndexScanDesc scan;
 247
 248         scan = index_beginscan_internal(indexRelation, nkeys, norderbys, snapshot);
 249
 250         /*
 251          * Save additional parameters into the scandesc.  Everything else was set
 252          * up by RelationGetIndexScan.
 253          */
 254         scan->heapRelation = heapRelation;
 255         scan->xs_snapshot = snapshot;
 256
 257         return scan;
 258 }
 259
 260 /*
 261  * index_beginscan_bitmap - start a scan of an index with amgetbitmap
 262  *
 263  * As above, caller had better be holding some lock on the parent heap
 264  * relation, even though it's not explicitly mentioned here.
 265  */
 266 IndexScanDesc
 267 index_beginscan_bitmap(Relation indexRelation,
 268                                            Snapshot snapshot,
 269                                            int nkeys)
 270 {
 271         IndexScanDesc scan;
 272
 273         scan = index_beginscan_internal(indexRelation, nkeys, 0, snapshot);
 274
 275         /*
 276          * Save additional parameters into the scandesc.  Everything else was set
 277          * up by RelationGetIndexScan.
 278          */
 279         scan->xs_snapshot = snapshot;
 280
 281         return scan;
 282 }
 283
 284 /*
 285  * index_beginscan_internal --- common code for index_beginscan variants
 286  */
 287 static IndexScanDesc
 288 index_beginscan_internal(Relation indexRelation,
 289                                                  int nkeys, int norderbys, Snapshot snapshot)
 290 {
 291         IndexScanDesc scan;
 292         FmgrInfo   *procedure;
 293
 294         RELATION_CHECKS;
 295         GET_REL_PROCEDURE(ambeginscan);
 296
 297         if (!(indexRelation->rd_am->ampredlocks))
 298                 PredicateLockRelation(indexRelation, snapshot);
 299
 300         /*
 301          * We hold a reference count to the relcache entry throughout the scan.
 302          */
 303         RelationIncrementReferenceCount(indexRelation);
 304
 305         /*
 306          * Tell the AM to open a scan.
 307          */
 308         scan = (IndexScanDesc)
 309                 DatumGetPointer(FunctionCall3(procedure,
 310                                                                           PointerGetDatum(indexRelation),
 311                                                                           Int32GetDatum(nkeys),
 312                                                                           Int32GetDatum(norderbys)));
 313
 314         return scan;
 315 }
 316
 317 /* ----------------
 318  *              index_rescan  - (re)start a scan of an index
 319  *
 320  * During a restart, the caller may specify a new set of scankeys and/or
 321  * orderbykeys; but the number of keys cannot differ from what index_beginscan
 322  * was told.  (Later we might relax that to "must not exceed", but currently
 323  * the index AMs tend to assume that scan->numberOfKeys is what to believe.)
 324  * To restart the scan without changing keys, pass NULL for the key arrays.
 325  * (Of course, keys *must* be passed on the first call, unless
 326  * scan->numberOfKeys is zero.)
 327  * ----------------
 328  */
 329 void
 330 index_rescan(IndexScanDesc scan,
 331                          ScanKey keys, int nkeys,
 332                          ScanKey orderbys, int norderbys)
 333 {
 334         FmgrInfo   *procedure;
 335
 336         SCAN_CHECKS;
 337         GET_SCAN_PROCEDURE(amrescan);
 338
 339         Assert(nkeys == scan->numberOfKeys);
 340         Assert(norderbys == scan->numberOfOrderBys);
 341
 342         /* Release any held pin on a heap page */
 343         if (BufferIsValid(scan->xs_cbuf))
 344         {
 345                 ReleaseBuffer(scan->xs_cbuf);
 346                 scan->xs_cbuf = InvalidBuffer;
 347         }
 348
 349         scan->xs_continue_hot = false;
 350
 351         scan->kill_prior_tuple = false;         /* for safety */
 352
 353         FunctionCall5(procedure,
 354                                   PointerGetDatum(scan),
 355                                   PointerGetDatum(keys),
 356                                   Int32GetDatum(nkeys),
 357                                   PointerGetDatum(orderbys),
 358                                   Int32GetDatum(norderbys));
 359 }
 360
 361 /* ----------------
 362  *              index_endscan - end a scan
 363  * ----------------
 364  */
 365 void
 366 index_endscan(IndexScanDesc scan)
 367 {
 368         FmgrInfo   *procedure;
 369
 370         SCAN_CHECKS;
 371         GET_SCAN_PROCEDURE(amendscan);
 372
 373         /* Release any held pin on a heap page */
 374         if (BufferIsValid(scan->xs_cbuf))
 375         {
 376                 ReleaseBuffer(scan->xs_cbuf);
 377                 scan->xs_cbuf = InvalidBuffer;
 378         }
 379
 380         /* End the AM's scan */
 381         FunctionCall1(procedure, PointerGetDatum(scan));
 382
 383         /* Release index refcount acquired by index_beginscan */
 384         RelationDecrementReferenceCount(scan->indexRelation);
 385
 386         /* Release the scan data structure itself */
 387         IndexScanEnd(scan);
 388 }
 389
 390 /* ----------------
 391  *              index_markpos  - mark a scan position
 392  * ----------------
 393  */
 394 void
 395 index_markpos(IndexScanDesc scan)
 396 {
 397         FmgrInfo   *procedure;
 398
 399         SCAN_CHECKS;
 400         GET_SCAN_PROCEDURE(ammarkpos);
 401
 402         FunctionCall1(procedure, PointerGetDatum(scan));
 403 }
 404
 405 /* ----------------
 406  *              index_restrpos  - restore a scan position
 407  *
 408  * NOTE: this only restores the internal scan state of the index AM.
 409  * The current result tuple (scan->xs_ctup) doesn't change.  See comments
 410  * for ExecRestrPos().
 411  *
 412  * NOTE: in the presence of HOT chains, mark/restore only works correctly
 413  * if the scan's snapshot is MVCC-safe; that ensures that there's at most one
 414  * returnable tuple in each HOT chain, and so restoring the prior state at the
 415  * granularity of the index AM is sufficient.  Since the only current user
 416  * of mark/restore functionality is nodeMergejoin.c, this effectively means
 417  * that merge-join plans only work for MVCC snapshots.  This could be fixed
 418  * if necessary, but for now it seems unimportant.
 419  * ----------------
 420  */
 421 void
 422 index_restrpos(IndexScanDesc scan)
 423 {
 424         FmgrInfo   *procedure;
 425
 426         Assert(IsMVCCSnapshot(scan->xs_snapshot));
 427
 428         SCAN_CHECKS;
 429         GET_SCAN_PROCEDURE(amrestrpos);
 430
 431         scan->xs_continue_hot = false;
 432
 433         scan->kill_prior_tuple = false;         /* for safety */
 434
 435         FunctionCall1(procedure, PointerGetDatum(scan));
 436 }
 437
 438 /* ----------------
 439  * index_getnext_tid - get the next TID from a scan
 440  *
 441  * The result is the next TID satisfying the scan keys,
 442  * or NULL if no more matching tuples exist.
 443  * ----------------
 444  */
 445 ItemPointer
 446 index_getnext_tid(IndexScanDesc scan, ScanDirection direction)
 447 {
 448         FmgrInfo   *procedure;
 449         bool            found;
 450
 451         SCAN_CHECKS;
 452         GET_SCAN_PROCEDURE(amgettuple);
 453
 454         Assert(TransactionIdIsValid(RecentGlobalXmin));
 455
 456         /*
 457          * The AM's amgettuple proc finds the next index entry matching the scan
 458          * keys, and puts the TID into scan->xs_ctup.t_self.  It should also set
 459          * scan->xs_recheck and possibly scan->xs_itup, though we pay no attention
 460          * to those fields here.
 461          */
 462         found = DatumGetBool(FunctionCall2(procedure,
 463                                                                            PointerGetDatum(scan),
 464                                                                            Int32GetDatum(direction)));
 465
 466         /* Reset kill flag immediately for safety */
 467         scan->kill_prior_tuple = false;
 468
 469         /* If we're out of index entries, we're done */
 470         if (!found)
 471         {
 472                 /* ... but first, release any held pin on a heap page */
 473                 if (BufferIsValid(scan->xs_cbuf))
 474                 {
 475                         ReleaseBuffer(scan->xs_cbuf);
 476                         scan->xs_cbuf = InvalidBuffer;
 477                 }
 478                 return NULL;
 479         }
 480
 481         pgstat_count_index_tuples(scan->indexRelation, 1);
 482
 483         /* Return the TID of the tuple we found. */
 484         return &scan->xs_ctup.t_self;
 485 }
 486
 487 /* ----------------
 488  *              index_fetch_heap - get the scan's next heap tuple
 489  *
 490  * The result is a visible heap tuple associated with the index TID most
 491  * recently fetched by index_getnext_tid, or NULL if no more matching tuples
 492  * exist.  (There can be more than one matching tuple because of HOT chains,
 493  * although when using an MVCC snapshot it should be impossible for more than
 494  * one such tuple to exist.)
 495  *
 496  * On success, the buffer containing the heap tup is pinned (the pin will be
 497  * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
 498  * call).
 499  *
 500  * Note: caller must check scan->xs_recheck, and perform rechecking of the
 501  * scan keys if required.  We do not do that here because we don't have
 502  * enough information to do it efficiently in the general case.
 503  * ----------------
 504  */
 505 HeapTuple
 506 index_fetch_heap(IndexScanDesc scan)
 507 {
 508         ItemPointer tid = &scan->xs_ctup.t_self;
 509         bool            all_dead = false;
 510         bool            got_heap_tuple;
 511
 512         /* We can skip the buffer-switching logic if we're in mid-HOT chain. */
 513         if (!scan->xs_continue_hot)
 514         {
 515                 /* Switch to correct buffer if we don't have it already */
 516                 Buffer          prev_buf = scan->xs_cbuf;
 517
 518                 scan->xs_cbuf = ReleaseAndReadBuffer(scan->xs_cbuf,
 519                                                                                          scan->heapRelation,
 520                                                                                          ItemPointerGetBlockNumber(tid));
 521
 522                 /*
 523                  * Prune page, but only if we weren't already on this page
 524                  */
 525                 if (prev_buf != scan->xs_cbuf)
 526                         heap_page_prune_opt(scan->heapRelation, scan->xs_cbuf);
 527         }
 528
 529         /* Obtain share-lock on the buffer so we can examine visibility */
 530         LockBuffer(scan->xs_cbuf, BUFFER_LOCK_SHARE);
 531         got_heap_tuple = heap_hot_search_buffer(tid, scan->heapRelation,
 532                                                                                         scan->xs_cbuf,
 533                                                                                         scan->xs_snapshot,
 534                                                                                         &scan->xs_ctup,
 535                                                                                         &all_dead,
 536                                                                                         !scan->xs_continue_hot);
 537         LockBuffer(scan->xs_cbuf, BUFFER_LOCK_UNLOCK);
 538
 539         if (got_heap_tuple)
 540         {
 541                 /*
 542                  * Only in a non-MVCC snapshot can more than one member of the HOT
 543                  * chain be visible.
 544                  */
 545                 scan->xs_continue_hot = !IsMVCCSnapshot(scan->xs_snapshot);
 546                 pgstat_count_heap_fetch(scan->indexRelation);
 547                 return &scan->xs_ctup;
 548         }
 549
 550         /* We've reached the end of the HOT chain. */
 551         scan->xs_continue_hot = false;
 552
 553         /*
 554          * If we scanned a whole HOT chain and found only dead tuples, tell index
 555          * AM to kill its entry for that TID (this will take effect in the next
 556          * amgettuple call, in index_getnext_tid).      We do not do this when in
 557          * recovery because it may violate MVCC to do so.  See comments in
 558          * RelationGetIndexScan().
 559          */
 560         if (!scan->xactStartedInRecovery)
 561                 scan->kill_prior_tuple = all_dead;
 562
 563         return NULL;
 564 }
 565
 566 /* ----------------
 567  *              index_getnext - get the next heap tuple from a scan
 568  *
 569  * The result is the next heap tuple satisfying the scan keys and the
 570  * snapshot, or NULL if no more matching tuples exist.
 571  *
 572  * On success, the buffer containing the heap tup is pinned (the pin will be
 573  * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
 574  * call).
 575  *
 576  * Note: caller must check scan->xs_recheck, and perform rechecking of the
 577  * scan keys if required.  We do not do that here because we don't have
 578  * enough information to do it efficiently in the general case.
 579  * ----------------
 580  */
 581 HeapTuple
 582 index_getnext(IndexScanDesc scan, ScanDirection direction)
 583 {
 584         HeapTuple       heapTuple;
 585         ItemPointer tid;
 586
 587         for (;;)
 588         {
 589                 if (scan->xs_continue_hot)
 590                 {
 591                         /*
 592                          * We are resuming scan of a HOT chain after having returned an
 593                          * earlier member.      Must still hold pin on current heap page.
 594                          */
 595                         Assert(BufferIsValid(scan->xs_cbuf));
 596                         Assert(ItemPointerGetBlockNumber(&scan->xs_ctup.t_self) ==
 597                                    BufferGetBlockNumber(scan->xs_cbuf));
 598                 }
 599                 else
 600                 {
 601                         /* Time to fetch the next TID from the index */
 602                         tid = index_getnext_tid(scan, direction);
 603
 604                         /* If we're out of index entries, we're done */
 605                         if (tid == NULL)
 606                                 break;
 607                 }
 608
 609                 /*
 610                  * Fetch the next (or only) visible heap tuple for this index entry.
 611                  * If we don't find anything, loop around and grab the next TID from
 612                  * the index.
 613                  */
 614                 heapTuple = index_fetch_heap(scan);
 615                 if (heapTuple != NULL)
 616                         return heapTuple;
 617         }
 618
 619         return NULL;                            /* failure exit */
 620 }
 621
 622 /* ----------------
 623  *              index_getbitmap - get all tuples at once from an index scan
 624  *
 625  * Adds the TIDs of all heap tuples satisfying the scan keys to a bitmap.
 626  * Since there's no interlock between the index scan and the eventual heap
 627  * access, this is only safe to use with MVCC-based snapshots: the heap
 628  * item slot could have been replaced by a newer tuple by the time we get
 629  * to it.
 630  *
 631  * Returns the number of matching tuples found.  (Note: this might be only
 632  * approximate, so it should only be used for statistical purposes.)
 633  * ----------------
 634  */
 635 int64
 636 index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap)
 637 {
 638         FmgrInfo   *procedure;
 639         int64           ntids;
 640         Datum           d;
 641
 642         SCAN_CHECKS;
 643         GET_SCAN_PROCEDURE(amgetbitmap);
 644
 645         /* just make sure this is false... */
 646         scan->kill_prior_tuple = false;
 647
 648         /*
 649          * have the am's getbitmap proc do all the work.
 650          */
 651         d = FunctionCall2(procedure,
 652                                           PointerGetDatum(scan),
 653                                           PointerGetDatum(bitmap));
 654
 655         ntids = DatumGetInt64(d);
 656
 657         /* If int8 is pass-by-ref, must free the result to avoid memory leak */
 658 #ifndef USE_FLOAT8_BYVAL
 659         pfree(DatumGetPointer(d));
 660 #endif
 661
 662         pgstat_count_index_tuples(scan->indexRelation, ntids);
 663
 664         return ntids;
 665 }
 666
 667 /* ----------------
 668  *              index_bulk_delete - do mass deletion of index entries
 669  *
 670  *              callback routine tells whether a given main-heap tuple is
 671  *              to be deleted
 672  *
 673  *              return value is an optional palloc'd struct of statistics
 674  * ----------------
 675  */
 676 IndexBulkDeleteResult *
 677 index_bulk_delete(IndexVacuumInfo *info,
 678                                   IndexBulkDeleteResult *stats,
 679                                   IndexBulkDeleteCallback callback,
 680                                   void *callback_state)
 681 {
 682         Relation        indexRelation = info->index;
 683         FmgrInfo        procedure;
 684         IndexBulkDeleteResult *result;
 685
 686         RELATION_CHECKS;
 687         GET_UNCACHED_REL_PROCEDURE(ambulkdelete);
 688
 689         result = (IndexBulkDeleteResult *)
 690                 DatumGetPointer(FunctionCall4(&procedure,
 691                                                                           PointerGetDatum(info),
 692                                                                           PointerGetDatum(stats),
 693                                                                           PointerGetDatum((Pointer) callback),
 694                                                                           PointerGetDatum(callback_state)));
 695
 696         return result;
 697 }
 698
 699 /* ----------------
 700  *              index_vacuum_cleanup - do post-deletion cleanup of an index
 701  *
 702  *              return value is an optional palloc'd struct of statistics
 703  * ----------------
 704  */
 705 IndexBulkDeleteResult *
 706 index_vacuum_cleanup(IndexVacuumInfo *info,
 707                                          IndexBulkDeleteResult *stats)
 708 {
 709         Relation        indexRelation = info->index;
 710         FmgrInfo        procedure;
 711         IndexBulkDeleteResult *result;
 712
 713         RELATION_CHECKS;
 714         GET_UNCACHED_REL_PROCEDURE(amvacuumcleanup);
 715
 716         result = (IndexBulkDeleteResult *)
 717                 DatumGetPointer(FunctionCall2(&procedure,
 718                                                                           PointerGetDatum(info),
 719                                                                           PointerGetDatum(stats)));
 720
 721         return result;
 722 }
 723
 724 /* ----------------
 725  *              index_can_return - does index support index-only scans?
 726  * ----------------
 727  */
 728 bool
 729 index_can_return(Relation indexRelation)
 730 {
 731         FmgrInfo   *procedure;
 732
 733         RELATION_CHECKS;
 734
 735         /* amcanreturn is optional; assume FALSE if not provided by AM */
 736         if (!RegProcedureIsValid(indexRelation->rd_am->amcanreturn))
 737                 return false;
 738
 739         GET_REL_PROCEDURE(amcanreturn);
 740
 741         return DatumGetBool(FunctionCall1(procedure,
 742                                                                           PointerGetDatum(indexRelation)));
 743 }
 744
 745 /* ----------------
 746  *              index_getprocid
 747  *
 748  *              Index access methods typically require support routines that are
 749  *              not directly the implementation of any WHERE-clause query operator
 750  *              and so cannot be kept in pg_amop.  Instead, such routines are kept
 751  *              in pg_amproc.  These registered procedure OIDs are assigned numbers
 752  *              according to a convention established by the access method.
 753  *              The general index code doesn't know anything about the routines
 754  *              involved; it just builds an ordered list of them for
 755  *              each attribute on which an index is defined.
 756  *
 757  *              As of Postgres 8.3, support routines within an operator family
 758  *              are further subdivided by the "left type" and "right type" of the
 759  *              query operator(s) that they support.  The "default" functions for a
 760  *              particular indexed attribute are those with both types equal to
 761  *              the index opclass' opcintype (note that this is subtly different
 762  *              from the indexed attribute's own type: it may be a binary-compatible
 763  *              type instead).  Only the default functions are stored in relcache
 764  *              entries --- access methods can use the syscache to look up non-default
 765  *              functions.
 766  *
 767  *              This routine returns the requested default procedure OID for a
 768  *              particular indexed attribute.
 769  * ----------------
 770  */
 771 RegProcedure
 772 index_getprocid(Relation irel,
 773                                 AttrNumber attnum,
 774                                 uint16 procnum)
 775 {
 776         RegProcedure *loc;
 777         int                     nproc;
 778         int                     procindex;
 779
 780         nproc = irel->rd_am->amsupport;
 781
 782         Assert(procnum > 0 && procnum <= (uint16) nproc);
 783
 784         procindex = (nproc * (attnum - 1)) + (procnum - 1);
 785
 786         loc = irel->rd_support;
 787
 788         Assert(loc != NULL);
 789
 790         return loc[procindex];
 791 }
 792
 793 /* ----------------
 794  *              index_getprocinfo
 795  *
 796  *              This routine allows index AMs to keep fmgr lookup info for
 797  *              support procs in the relcache.  As above, only the "default"
 798  *              functions for any particular indexed attribute are cached.
 799  *
 800  * Note: the return value points into cached data that will be lost during
 801  * any relcache rebuild!  Therefore, either use the callinfo right away,
 802  * or save it only after having acquired some type of lock on the index rel.
 803  * ----------------
 804  */
 805 FmgrInfo *
 806 index_getprocinfo(Relation irel,
 807                                   AttrNumber attnum,
 808                                   uint16 procnum)
 809 {
 810         FmgrInfo   *locinfo;
 811         int                     nproc;
 812         int                     procindex;
 813
 814         nproc = irel->rd_am->amsupport;
 815
 816         Assert(procnum > 0 && procnum <= (uint16) nproc);
 817
 818         procindex = (nproc * (attnum - 1)) + (procnum - 1);
 819
 820         locinfo = irel->rd_supportinfo;
 821
 822         Assert(locinfo != NULL);
 823
 824         locinfo += procindex;
 825
 826         /* Initialize the lookup info if first time through */
 827         if (locinfo->fn_oid == InvalidOid)
 828         {
 829                 RegProcedure *loc = irel->rd_support;
 830                 RegProcedure procId;
 831
 832                 Assert(loc != NULL);
 833
 834                 procId = loc[procindex];
 835
 836                 /*
 837                  * Complain if function was not found during IndexSupportInitialize.
 838                  * This should not happen unless the system tables contain bogus
 839                  * entries for the index opclass.  (If an AM wants to allow a support
 840                  * function to be optional, it can use index_getprocid.)
 841                  */
 842                 if (!RegProcedureIsValid(procId))
 843                         elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
 844                                  procnum, attnum, RelationGetRelationName(irel));
 845
 846                 fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
 847         }
 848
 849         return locinfo;
 850 }