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) 1996-2013, 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 "catalog/index.h"
  71 #include "pgstat.h"
  72 #include "storage/bufmgr.h"
  73 #include "storage/lmgr.h"
  74 #include "storage/predicate.h"
  75 #include "utils/snapmgr.h"
  76 #include "utils/tqual.h"
  77
  78
  79 /* ----------------------------------------------------------------
  80  *                                      macros used in index_ routines
  81  *
  82  * Note: the ReindexIsProcessingIndex() check in RELATION_CHECKS is there
  83  * to check that we don't try to scan or do retail insertions into an index
  84  * that is currently being rebuilt or pending rebuild.  This helps to catch
  85  * things that don't work when reindexing system catalogs.  The assertion
  86  * doesn't prevent the actual rebuild because we don't use RELATION_CHECKS
  87  * when calling the index AM's ambuild routine, and there is no reason for
  88  * ambuild to call its subsidiary routines through this file.
  89  * ----------------------------------------------------------------
  90  */
  91 #define RELATION_CHECKS \
  92 ( \
  93         AssertMacro(RelationIsValid(indexRelation)), \
  94         AssertMacro(PointerIsValid(indexRelation->rd_am)), \
  95         AssertMacro(!ReindexIsProcessingIndex(RelationGetRelid(indexRelation))) \
  96 )
  97
  98 #define SCAN_CHECKS \
  99 ( \
 100         AssertMacro(IndexScanIsValid(scan)), \
 101         AssertMacro(RelationIsValid(scan->indexRelation)), \
 102         AssertMacro(PointerIsValid(scan->indexRelation->rd_am)) \
 103 )
 104
 105 #define GET_REL_PROCEDURE(pname) \
 106 do { \
 107         procedure = &indexRelation->rd_aminfo->pname; \
 108         if (!OidIsValid(procedure->fn_oid)) \
 109         { \
 110                 RegProcedure    procOid = indexRelation->rd_am->pname; \
 111                 if (!RegProcedureIsValid(procOid)) \
 112                         elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
 113                 fmgr_info_cxt(procOid, procedure, indexRelation->rd_indexcxt); \
 114         } \
 115 } while(0)
 116
 117 #define GET_UNCACHED_REL_PROCEDURE(pname) \
 118 do { \
 119         if (!RegProcedureIsValid(indexRelation->rd_am->pname)) \
 120                 elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
 121         fmgr_info(indexRelation->rd_am->pname, &procedure); \
 122 } while(0)
 123
 124 #define GET_SCAN_PROCEDURE(pname) \
 125 do { \
 126         procedure = &scan->indexRelation->rd_aminfo->pname; \
 127         if (!OidIsValid(procedure->fn_oid)) \
 128         { \
 129                 RegProcedure    procOid = scan->indexRelation->rd_am->pname; \
 130                 if (!RegProcedureIsValid(procOid)) \
 131                         elog(ERROR, "invalid %s regproc", CppAsString(pname)); \
 132                 fmgr_info_cxt(procOid, procedure, scan->indexRelation->rd_indexcxt); \
 133         } \
 134 } while(0)
 135
 136 static IndexScanDesc index_beginscan_internal(Relation indexRelation,
 137                                                  int nkeys, int norderbys, Snapshot snapshot);
 138
 139
 140 /* ----------------------------------------------------------------
 141  *                                 index_ interface functions
 142  * ----------------------------------------------------------------
 143  */
 144
 145 /* ----------------
 146  *              index_open - open an index relation by relation OID
 147  *
 148  *              If lockmode is not "NoLock", the specified kind of lock is
 149  *              obtained on the index.  (Generally, NoLock should only be
 150  *              used if the caller knows it has some appropriate lock on the
 151  *              index already.)
 152  *
 153  *              An error is raised if the index does not exist.
 154  *
 155  *              This is a convenience routine adapted for indexscan use.
 156  *              Some callers may prefer to use relation_open directly.
 157  * ----------------
 158  */
 159 Relation
 160 index_open(Oid relationId, LOCKMODE lockmode)
 161 {
 162         Relation        r;
 163
 164         r = relation_open(relationId, lockmode);
 165
 166         if (r->rd_rel->relkind != RELKIND_INDEX)
 167                 ereport(ERROR,
 168                                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
 169                                  errmsg("\"%s\" is not an index",
 170                                                 RelationGetRelationName(r))));
 171
 172         return r;
 173 }
 174
 175 /* ----------------
 176  *              index_close - close an index relation
 177  *
 178  *              If lockmode is not "NoLock", we then release the specified lock.
 179  *
 180  *              Note that it is often sensible to hold a lock beyond index_close;
 181  *              in that case, the lock is released automatically at xact end.
 182  * ----------------
 183  */
 184 void
 185 index_close(Relation relation, LOCKMODE lockmode)
 186 {
 187         LockRelId       relid = relation->rd_lockInfo.lockRelId;
 188
 189         Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
 190
 191         /* The relcache does the real work... */
 192         RelationClose(relation);
 193
 194         if (lockmode != NoLock)
 195                 UnlockRelationId(&relid, lockmode);
 196 }
 197
 198 /* ----------------
 199  *              index_insert - insert an index tuple into a relation
 200  * ----------------
 201  */
 202 bool
 203 index_insert(Relation indexRelation,
 204                          Datum *values,
 205                          bool *isnull,
 206                          ItemPointer heap_t_ctid,
 207                          Relation heapRelation,
 208                          IndexUniqueCheck checkUnique)
 209 {
 210         FmgrInfo   *procedure;
 211
 212         RELATION_CHECKS;
 213         GET_REL_PROCEDURE(aminsert);
 214
 215         if (!(indexRelation->rd_am->ampredlocks))
 216                 CheckForSerializableConflictIn(indexRelation,
 217                                                                            (HeapTuple) NULL,
 218                                                                            InvalidBuffer);
 219
 220         /*
 221          * have the am's insert proc do all the work.
 222          */
 223         return DatumGetBool(FunctionCall6(procedure,
 224                                                                           PointerGetDatum(indexRelation),
 225                                                                           PointerGetDatum(values),
 226                                                                           PointerGetDatum(isnull),
 227                                                                           PointerGetDatum(heap_t_ctid),
 228                                                                           PointerGetDatum(heapRelation),
 229                                                                           Int32GetDatum((int32) checkUnique)));
 230 }
 231
 232 /*
 233  * index_beginscan - start a scan of an index with amgettuple
 234  *
 235  * Caller must be holding suitable locks on the heap and the index.
 236  */
 237 IndexScanDesc
 238 index_beginscan(Relation heapRelation,
 239                                 Relation indexRelation,
 240                                 Snapshot snapshot,
 241                                 int nkeys, int norderbys)
 242 {
 243         IndexScanDesc scan;
 244
 245         scan = index_beginscan_internal(indexRelation, nkeys, norderbys, snapshot);
 246
 247         /*
 248          * Save additional parameters into the scandesc.  Everything else was set
 249          * up by RelationGetIndexScan.
 250          */
 251         scan->heapRelation = heapRelation;
 252         scan->xs_snapshot = snapshot;
 253
 254         return scan;
 255 }
 256
 257 /*
 258  * index_beginscan_bitmap - start a scan of an index with amgetbitmap
 259  *
 260  * As above, caller had better be holding some lock on the parent heap
 261  * relation, even though it's not explicitly mentioned here.
 262  */
 263 IndexScanDesc
 264 index_beginscan_bitmap(Relation indexRelation,
 265                                            Snapshot snapshot,
 266                                            int nkeys)
 267 {
 268         IndexScanDesc scan;
 269
 270         scan = index_beginscan_internal(indexRelation, nkeys, 0, snapshot);
 271
 272         /*
 273          * Save additional parameters into the scandesc.  Everything else was set
 274          * up by RelationGetIndexScan.
 275          */
 276         scan->xs_snapshot = snapshot;
 277
 278         return scan;
 279 }
 280
 281 /*
 282  * index_beginscan_internal --- common code for index_beginscan variants
 283  */
 284 static IndexScanDesc
 285 index_beginscan_internal(Relation indexRelation,
 286                                                  int nkeys, int norderbys, Snapshot snapshot)
 287 {
 288         IndexScanDesc scan;
 289         FmgrInfo   *procedure;
 290
 291         RELATION_CHECKS;
 292         GET_REL_PROCEDURE(ambeginscan);
 293
 294         if (!(indexRelation->rd_am->ampredlocks))
 295                 PredicateLockRelation(indexRelation, snapshot);
 296
 297         /*
 298          * We hold a reference count to the relcache entry throughout the scan.
 299          */
 300         RelationIncrementReferenceCount(indexRelation);
 301
 302         /*
 303          * Tell the AM to open a scan.
 304          */
 305         scan = (IndexScanDesc)
 306                 DatumGetPointer(FunctionCall3(procedure,
 307                                                                           PointerGetDatum(indexRelation),
 308                                                                           Int32GetDatum(nkeys),
 309                                                                           Int32GetDatum(norderbys)));
 310
 311         return scan;
 312 }
 313
 314 /* ----------------
 315  *              index_rescan  - (re)start a scan of an index
 316  *
 317  * During a restart, the caller may specify a new set of scankeys and/or
 318  * orderbykeys; but the number of keys cannot differ from what index_beginscan
 319  * was told.  (Later we might relax that to "must not exceed", but currently
 320  * the index AMs tend to assume that scan->numberOfKeys is what to believe.)
 321  * To restart the scan without changing keys, pass NULL for the key arrays.
 322  * (Of course, keys *must* be passed on the first call, unless
 323  * scan->numberOfKeys is zero.)
 324  * ----------------
 325  */
 326 void
 327 index_rescan(IndexScanDesc scan,
 328                          ScanKey keys, int nkeys,
 329                          ScanKey orderbys, int norderbys)
 330 {
 331         FmgrInfo   *procedure;
 332
 333         SCAN_CHECKS;
 334         GET_SCAN_PROCEDURE(amrescan);
 335
 336         Assert(nkeys == scan->numberOfKeys);
 337         Assert(norderbys == scan->numberOfOrderBys);
 338
 339         /* Release any held pin on a heap page */
 340         if (BufferIsValid(scan->xs_cbuf))
 341         {
 342                 ReleaseBuffer(scan->xs_cbuf);
 343                 scan->xs_cbuf = InvalidBuffer;
 344         }
 345
 346         scan->xs_continue_hot = false;
 347
 348         scan->kill_prior_tuple = false;         /* for safety */
 349
 350         FunctionCall5(procedure,
 351                                   PointerGetDatum(scan),
 352                                   PointerGetDatum(keys),
 353                                   Int32GetDatum(nkeys),
 354                                   PointerGetDatum(orderbys),
 355                                   Int32GetDatum(norderbys));
 356 }
 357
 358 /* ----------------
 359  *              index_endscan - end a scan
 360  * ----------------
 361  */
 362 void
 363 index_endscan(IndexScanDesc scan)
 364 {
 365         FmgrInfo   *procedure;
 366
 367         SCAN_CHECKS;
 368         GET_SCAN_PROCEDURE(amendscan);
 369
 370         /* Release any held pin on a heap page */
 371         if (BufferIsValid(scan->xs_cbuf))
 372         {
 373                 ReleaseBuffer(scan->xs_cbuf);
 374                 scan->xs_cbuf = InvalidBuffer;
 375         }
 376
 377         /* End the AM's scan */
 378         FunctionCall1(procedure, PointerGetDatum(scan));
 379
 380         /* Release index refcount acquired by index_beginscan */
 381         RelationDecrementReferenceCount(scan->indexRelation);
 382
 383         /* Release the scan data structure itself */
 384         IndexScanEnd(scan);
 385 }
 386
 387 /* ----------------
 388  *              index_markpos  - mark a scan position
 389  * ----------------
 390  */
 391 void
 392 index_markpos(IndexScanDesc scan)
 393 {
 394         FmgrInfo   *procedure;
 395
 396         SCAN_CHECKS;
 397         GET_SCAN_PROCEDURE(ammarkpos);
 398
 399         FunctionCall1(procedure, PointerGetDatum(scan));
 400 }
 401
 402 /* ----------------
 403  *              index_restrpos  - restore a scan position
 404  *
 405  * NOTE: this only restores the internal scan state of the index AM.
 406  * The current result tuple (scan->xs_ctup) doesn't change.  See comments
 407  * for ExecRestrPos().
 408  *
 409  * NOTE: in the presence of HOT chains, mark/restore only works correctly
 410  * if the scan's snapshot is MVCC-safe; that ensures that there's at most one
 411  * returnable tuple in each HOT chain, and so restoring the prior state at the
 412  * granularity of the index AM is sufficient.  Since the only current user
 413  * of mark/restore functionality is nodeMergejoin.c, this effectively means
 414  * that merge-join plans only work for MVCC snapshots.  This could be fixed
 415  * if necessary, but for now it seems unimportant.
 416  * ----------------
 417  */
 418 void
 419 index_restrpos(IndexScanDesc scan)
 420 {
 421         FmgrInfo   *procedure;
 422
 423         Assert(IsMVCCSnapshot(scan->xs_snapshot));
 424
 425         SCAN_CHECKS;
 426         GET_SCAN_PROCEDURE(amrestrpos);
 427
 428         scan->xs_continue_hot = false;
 429
 430         scan->kill_prior_tuple = false;         /* for safety */
 431
 432         FunctionCall1(procedure, PointerGetDatum(scan));
 433 }
 434
 435 /* ----------------
 436  * index_getnext_tid - get the next TID from a scan
 437  *
 438  * The result is the next TID satisfying the scan keys,
 439  * or NULL if no more matching tuples exist.
 440  * ----------------
 441  */
 442 ItemPointer
 443 index_getnext_tid(IndexScanDesc scan, ScanDirection direction)
 444 {
 445         FmgrInfo   *procedure;
 446         bool            found;
 447
 448         SCAN_CHECKS;
 449         GET_SCAN_PROCEDURE(amgettuple);
 450
 451         Assert(TransactionIdIsValid(RecentGlobalXmin));
 452
 453         /*
 454          * The AM's amgettuple proc finds the next index entry matching the scan
 455          * keys, and puts the TID into scan->xs_ctup.t_self.  It should also set
 456          * scan->xs_recheck and possibly scan->xs_itup, though we pay no attention
 457          * to those fields here.
 458          */
 459         found = DatumGetBool(FunctionCall2(procedure,
 460                                                                            PointerGetDatum(scan),
 461                                                                            Int32GetDatum(direction)));
 462
 463         /* Reset kill flag immediately for safety */
 464         scan->kill_prior_tuple = false;
 465
 466         /* If we're out of index entries, we're done */
 467         if (!found)
 468         {
 469                 /* ... but first, release any held pin on a heap page */
 470                 if (BufferIsValid(scan->xs_cbuf))
 471                 {
 472                         ReleaseBuffer(scan->xs_cbuf);
 473                         scan->xs_cbuf = InvalidBuffer;
 474                 }
 475                 return NULL;
 476         }
 477
 478         pgstat_count_index_tuples(scan->indexRelation, 1);
 479
 480         /* Return the TID of the tuple we found. */
 481         return &scan->xs_ctup.t_self;
 482 }
 483
 484 /* ----------------
 485  *              index_fetch_heap - get the scan's next heap tuple
 486  *
 487  * The result is a visible heap tuple associated with the index TID most
 488  * recently fetched by index_getnext_tid, or NULL if no more matching tuples
 489  * exist.  (There can be more than one matching tuple because of HOT chains,
 490  * although when using an MVCC snapshot it should be impossible for more than
 491  * one such tuple to exist.)
 492  *
 493  * On success, the buffer containing the heap tup is pinned (the pin will be
 494  * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
 495  * call).
 496  *
 497  * Note: caller must check scan->xs_recheck, and perform rechecking of the
 498  * scan keys if required.  We do not do that here because we don't have
 499  * enough information to do it efficiently in the general case.
 500  * ----------------
 501  */
 502 HeapTuple
 503 index_fetch_heap(IndexScanDesc scan)
 504 {
 505         ItemPointer tid = &scan->xs_ctup.t_self;
 506         bool            all_dead = false;
 507         bool            got_heap_tuple;
 508
 509         /* We can skip the buffer-switching logic if we're in mid-HOT chain. */
 510         if (!scan->xs_continue_hot)
 511         {
 512                 /* Switch to correct buffer if we don't have it already */
 513                 Buffer          prev_buf = scan->xs_cbuf;
 514
 515                 scan->xs_cbuf = ReleaseAndReadBuffer(scan->xs_cbuf,
 516                                                                                          scan->heapRelation,
 517                                                                                          ItemPointerGetBlockNumber(tid));
 518
 519                 /*
 520                  * Prune page, but only if we weren't already on this page
 521                  */
 522                 if (prev_buf != scan->xs_cbuf)
 523                         heap_page_prune_opt(scan->heapRelation, scan->xs_cbuf,
 524                                                                 RecentGlobalXmin);
 525         }
 526
 527         /* Obtain share-lock on the buffer so we can examine visibility */
 528         LockBuffer(scan->xs_cbuf, BUFFER_LOCK_SHARE);
 529         got_heap_tuple = heap_hot_search_buffer(tid, scan->heapRelation,
 530                                                                                         scan->xs_cbuf,
 531                                                                                         scan->xs_snapshot,
 532                                                                                         &scan->xs_ctup,
 533                                                                                         &all_dead,
 534                                                                                         !scan->xs_continue_hot);
 535         LockBuffer(scan->xs_cbuf, BUFFER_LOCK_UNLOCK);
 536
 537         if (got_heap_tuple)
 538         {
 539                 /*
 540                  * Only in a non-MVCC snapshot can more than one member of the HOT
 541                  * chain be visible.
 542                  */
 543                 scan->xs_continue_hot = !IsMVCCSnapshot(scan->xs_snapshot);
 544                 pgstat_count_heap_fetch(scan->indexRelation);
 545                 return &scan->xs_ctup;
 546         }
 547
 548         /* We've reached the end of the HOT chain. */
 549         scan->xs_continue_hot = false;
 550
 551         /*
 552          * If we scanned a whole HOT chain and found only dead tuples, tell index
 553          * AM to kill its entry for that TID (this will take effect in the next
 554          * amgettuple call, in index_getnext_tid).      We do not do this when in
 555          * recovery because it may violate MVCC to do so.  See comments in
 556          * RelationGetIndexScan().
 557          */
 558         if (!scan->xactStartedInRecovery)
 559                 scan->kill_prior_tuple = all_dead;
 560
 561         return NULL;
 562 }
 563
 564 /* ----------------
 565  *              index_getnext - get the next heap tuple from a scan
 566  *
 567  * The result is the next heap tuple satisfying the scan keys and the
 568  * snapshot, or NULL if no more matching tuples exist.
 569  *
 570  * On success, the buffer containing the heap tup is pinned (the pin will be
 571  * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
 572  * call).
 573  *
 574  * Note: caller must check scan->xs_recheck, and perform rechecking of the
 575  * scan keys if required.  We do not do that here because we don't have
 576  * enough information to do it efficiently in the general case.
 577  * ----------------
 578  */
 579 HeapTuple
 580 index_getnext(IndexScanDesc scan, ScanDirection direction)
 581 {
 582         HeapTuple       heapTuple;
 583         ItemPointer tid;
 584
 585         for (;;)
 586         {
 587                 if (scan->xs_continue_hot)
 588                 {
 589                         /*
 590                          * We are resuming scan of a HOT chain after having returned an
 591                          * earlier member.      Must still hold pin on current heap page.
 592                          */
 593                         Assert(BufferIsValid(scan->xs_cbuf));
 594                         Assert(ItemPointerGetBlockNumber(&scan->xs_ctup.t_self) ==
 595                                    BufferGetBlockNumber(scan->xs_cbuf));
 596                 }
 597                 else
 598                 {
 599                         /* Time to fetch the next TID from the index */
 600                         tid = index_getnext_tid(scan, direction);
 601
 602                         /* If we're out of index entries, we're done */
 603                         if (tid == NULL)
 604                                 break;
 605                 }
 606
 607                 /*
 608                  * Fetch the next (or only) visible heap tuple for this index entry.
 609                  * If we don't find anything, loop around and grab the next TID from
 610                  * the index.
 611                  */
 612                 heapTuple = index_fetch_heap(scan);
 613                 if (heapTuple != NULL)
 614                         return heapTuple;
 615         }
 616
 617         return NULL;                            /* failure exit */
 618 }
 619
 620 /* ----------------
 621  *              index_getbitmap - get all tuples at once from an index scan
 622  *
 623  * Adds the TIDs of all heap tuples satisfying the scan keys to a bitmap.
 624  * Since there's no interlock between the index scan and the eventual heap
 625  * access, this is only safe to use with MVCC-based snapshots: the heap
 626  * item slot could have been replaced by a newer tuple by the time we get
 627  * to it.
 628  *
 629  * Returns the number of matching tuples found.  (Note: this might be only
 630  * approximate, so it should only be used for statistical purposes.)
 631  * ----------------
 632  */
 633 int64
 634 index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap)
 635 {
 636         FmgrInfo   *procedure;
 637         int64           ntids;
 638         Datum           d;
 639
 640         SCAN_CHECKS;
 641         GET_SCAN_PROCEDURE(amgetbitmap);
 642
 643         /* just make sure this is false... */
 644         scan->kill_prior_tuple = false;
 645
 646         /*
 647          * have the am's getbitmap proc do all the work.
 648          */
 649         d = FunctionCall2(procedure,
 650                                           PointerGetDatum(scan),
 651                                           PointerGetDatum(bitmap));
 652
 653         ntids = DatumGetInt64(d);
 654
 655         /* If int8 is pass-by-ref, must free the result to avoid memory leak */
 656 #ifndef USE_FLOAT8_BYVAL
 657         pfree(DatumGetPointer(d));
 658 #endif
 659
 660         pgstat_count_index_tuples(scan->indexRelation, ntids);
 661
 662         return ntids;
 663 }
 664
 665 /* ----------------
 666  *              index_bulk_delete - do mass deletion of index entries
 667  *
 668  *              callback routine tells whether a given main-heap tuple is
 669  *              to be deleted
 670  *
 671  *              return value is an optional palloc'd struct of statistics
 672  * ----------------
 673  */
 674 IndexBulkDeleteResult *
 675 index_bulk_delete(IndexVacuumInfo *info,
 676                                   IndexBulkDeleteResult *stats,
 677                                   IndexBulkDeleteCallback callback,
 678                                   void *callback_state)
 679 {
 680         Relation        indexRelation = info->index;
 681         FmgrInfo        procedure;
 682         IndexBulkDeleteResult *result;
 683
 684         RELATION_CHECKS;
 685         GET_UNCACHED_REL_PROCEDURE(ambulkdelete);
 686
 687         result = (IndexBulkDeleteResult *)
 688                 DatumGetPointer(FunctionCall4(&procedure,
 689                                                                           PointerGetDatum(info),
 690                                                                           PointerGetDatum(stats),
 691                                                                           PointerGetDatum((Pointer) callback),
 692                                                                           PointerGetDatum(callback_state)));
 693
 694         return result;
 695 }
 696
 697 /* ----------------
 698  *              index_vacuum_cleanup - do post-deletion cleanup of an index
 699  *
 700  *              return value is an optional palloc'd struct of statistics
 701  * ----------------
 702  */
 703 IndexBulkDeleteResult *
 704 index_vacuum_cleanup(IndexVacuumInfo *info,
 705                                          IndexBulkDeleteResult *stats)
 706 {
 707         Relation        indexRelation = info->index;
 708         FmgrInfo        procedure;
 709         IndexBulkDeleteResult *result;
 710
 711         RELATION_CHECKS;
 712         GET_UNCACHED_REL_PROCEDURE(amvacuumcleanup);
 713
 714         result = (IndexBulkDeleteResult *)
 715                 DatumGetPointer(FunctionCall2(&procedure,
 716                                                                           PointerGetDatum(info),
 717                                                                           PointerGetDatum(stats)));
 718
 719         return result;
 720 }
 721
 722 /* ----------------
 723  *              index_can_return - does index support index-only scans?
 724  * ----------------
 725  */
 726 bool
 727 index_can_return(Relation indexRelation)
 728 {
 729         FmgrInfo   *procedure;
 730
 731         RELATION_CHECKS;
 732
 733         /* amcanreturn is optional; assume FALSE if not provided by AM */
 734         if (!RegProcedureIsValid(indexRelation->rd_am->amcanreturn))
 735                 return false;
 736
 737         GET_REL_PROCEDURE(amcanreturn);
 738
 739         return DatumGetBool(FunctionCall1(procedure,
 740                                                                           PointerGetDatum(indexRelation)));
 741 }
 742
 743 /* ----------------
 744  *              index_getprocid
 745  *
 746  *              Index access methods typically require support routines that are
 747  *              not directly the implementation of any WHERE-clause query operator
 748  *              and so cannot be kept in pg_amop.  Instead, such routines are kept
 749  *              in pg_amproc.  These registered procedure OIDs are assigned numbers
 750  *              according to a convention established by the access method.
 751  *              The general index code doesn't know anything about the routines
 752  *              involved; it just builds an ordered list of them for
 753  *              each attribute on which an index is defined.
 754  *
 755  *              As of Postgres 8.3, support routines within an operator family
 756  *              are further subdivided by the "left type" and "right type" of the
 757  *              query operator(s) that they support.  The "default" functions for a
 758  *              particular indexed attribute are those with both types equal to
 759  *              the index opclass' opcintype (note that this is subtly different
 760  *              from the indexed attribute's own type: it may be a binary-compatible
 761  *              type instead).  Only the default functions are stored in relcache
 762  *              entries --- access methods can use the syscache to look up non-default
 763  *              functions.
 764  *
 765  *              This routine returns the requested default procedure OID for a
 766  *              particular indexed attribute.
 767  * ----------------
 768  */
 769 RegProcedure
 770 index_getprocid(Relation irel,
 771                                 AttrNumber attnum,
 772                                 uint16 procnum)
 773 {
 774         RegProcedure *loc;
 775         int                     nproc;
 776         int                     procindex;
 777
 778         nproc = irel->rd_am->amsupport;
 779
 780         Assert(procnum > 0 && procnum <= (uint16) nproc);
 781
 782         procindex = (nproc * (attnum - 1)) + (procnum - 1);
 783
 784         loc = irel->rd_support;
 785
 786         Assert(loc != NULL);
 787
 788         return loc[procindex];
 789 }
 790
 791 /* ----------------
 792  *              index_getprocinfo
 793  *
 794  *              This routine allows index AMs to keep fmgr lookup info for
 795  *              support procs in the relcache.  As above, only the "default"
 796  *              functions for any particular indexed attribute are cached.
 797  *
 798  * Note: the return value points into cached data that will be lost during
 799  * any relcache rebuild!  Therefore, either use the callinfo right away,
 800  * or save it only after having acquired some type of lock on the index rel.
 801  * ----------------
 802  */
 803 FmgrInfo *
 804 index_getprocinfo(Relation irel,
 805                                   AttrNumber attnum,
 806                                   uint16 procnum)
 807 {
 808         FmgrInfo   *locinfo;
 809         int                     nproc;
 810         int                     procindex;
 811
 812         nproc = irel->rd_am->amsupport;
 813
 814         Assert(procnum > 0 && procnum <= (uint16) nproc);
 815
 816         procindex = (nproc * (attnum - 1)) + (procnum - 1);
 817
 818         locinfo = irel->rd_supportinfo;
 819
 820         Assert(locinfo != NULL);
 821
 822         locinfo += procindex;
 823
 824         /* Initialize the lookup info if first time through */
 825         if (locinfo->fn_oid == InvalidOid)
 826         {
 827                 RegProcedure *loc = irel->rd_support;
 828                 RegProcedure procId;
 829
 830                 Assert(loc != NULL);
 831
 832                 procId = loc[procindex];
 833
 834                 /*
 835                  * Complain if function was not found during IndexSupportInitialize.
 836                  * This should not happen unless the system tables contain bogus
 837                  * entries for the index opclass.  (If an AM wants to allow a support
 838                  * function to be optional, it can use index_getprocid.)
 839                  */
 840                 if (!RegProcedureIsValid(procId))
 841                         elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
 842                                  procnum, attnum, RelationGetRelationName(irel));
 843
 844                 fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
 845         }
 846
 847         return locinfo;
 848 }