LCOV - code coverage report
Current view: top level - src/backend/access/index - indexam.c (source / functions) Hit Total Coverage
Test: PostgreSQL 16devel Lines: 199 203 98.0 %
Date: 2023-01-27 18:10:33 Functions: 25 25 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * indexam.c
       4             :  *    general index access method routines
       5             :  *
       6             :  * Portions Copyright (c) 1996-2023, 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_parallelscan_estimate - estimate shared memory for parallel scan
      24             :  *      index_parallelscan_initialize - initialize parallel scan
      25             :  *      index_parallelrescan  - (re)start a parallel scan of an index
      26             :  *      index_beginscan_parallel - join parallel index scan
      27             :  *      index_getnext_tid   - get the next TID from a scan
      28             :  *      index_fetch_heap        - get the scan's next heap tuple
      29             :  *      index_getnext_slot  - get the next tuple from a scan
      30             :  *      index_getbitmap - get all tuples from a scan
      31             :  *      index_bulk_delete   - bulk deletion of index tuples
      32             :  *      index_vacuum_cleanup    - post-deletion cleanup of an index
      33             :  *      index_can_return    - does index support index-only scans?
      34             :  *      index_getprocid - get a support procedure OID
      35             :  *      index_getprocinfo - get a support procedure's lookup info
      36             :  *
      37             :  * NOTES
      38             :  *      This file contains the index_ routines which used
      39             :  *      to be a scattered collection of stuff in access/genam.
      40             :  *
      41             :  *-------------------------------------------------------------------------
      42             :  */
      43             : 
      44             : #include "postgres.h"
      45             : 
      46             : #include "access/amapi.h"
      47             : #include "access/heapam.h"
      48             : #include "access/reloptions.h"
      49             : #include "access/relscan.h"
      50             : #include "access/tableam.h"
      51             : #include "access/transam.h"
      52             : #include "access/xlog.h"
      53             : #include "catalog/index.h"
      54             : #include "catalog/pg_amproc.h"
      55             : #include "catalog/pg_type.h"
      56             : #include "commands/defrem.h"
      57             : #include "nodes/makefuncs.h"
      58             : #include "pgstat.h"
      59             : #include "storage/bufmgr.h"
      60             : #include "storage/lmgr.h"
      61             : #include "storage/predicate.h"
      62             : #include "utils/ruleutils.h"
      63             : #include "utils/snapmgr.h"
      64             : #include "utils/syscache.h"
      65             : 
      66             : 
      67             : /* ----------------------------------------------------------------
      68             :  *                  macros used in index_ routines
      69             :  *
      70             :  * Note: the ReindexIsProcessingIndex() check in RELATION_CHECKS is there
      71             :  * to check that we don't try to scan or do retail insertions into an index
      72             :  * that is currently being rebuilt or pending rebuild.  This helps to catch
      73             :  * things that don't work when reindexing system catalogs.  The assertion
      74             :  * doesn't prevent the actual rebuild because we don't use RELATION_CHECKS
      75             :  * when calling the index AM's ambuild routine, and there is no reason for
      76             :  * ambuild to call its subsidiary routines through this file.
      77             :  * ----------------------------------------------------------------
      78             :  */
      79             : #define RELATION_CHECKS \
      80             : ( \
      81             :     AssertMacro(RelationIsValid(indexRelation)), \
      82             :     AssertMacro(PointerIsValid(indexRelation->rd_indam)), \
      83             :     AssertMacro(!ReindexIsProcessingIndex(RelationGetRelid(indexRelation))) \
      84             : )
      85             : 
      86             : #define SCAN_CHECKS \
      87             : ( \
      88             :     AssertMacro(IndexScanIsValid(scan)), \
      89             :     AssertMacro(RelationIsValid(scan->indexRelation)), \
      90             :     AssertMacro(PointerIsValid(scan->indexRelation->rd_indam)) \
      91             : )
      92             : 
      93             : #define CHECK_REL_PROCEDURE(pname) \
      94             : do { \
      95             :     if (indexRelation->rd_indam->pname == NULL) \
      96             :         elog(ERROR, "function \"%s\" is not defined for index \"%s\"", \
      97             :              CppAsString(pname), RelationGetRelationName(indexRelation)); \
      98             : } while(0)
      99             : 
     100             : #define CHECK_SCAN_PROCEDURE(pname) \
     101             : do { \
     102             :     if (scan->indexRelation->rd_indam->pname == NULL) \
     103             :         elog(ERROR, "function \"%s\" is not defined for index \"%s\"", \
     104             :              CppAsString(pname), RelationGetRelationName(scan->indexRelation)); \
     105             : } while(0)
     106             : 
     107             : static IndexScanDesc index_beginscan_internal(Relation indexRelation,
     108             :                                               int nkeys, int norderbys, Snapshot snapshot,
     109             :                                               ParallelIndexScanDesc pscan, bool temp_snap);
     110             : 
     111             : 
     112             : /* ----------------------------------------------------------------
     113             :  *                 index_ interface functions
     114             :  * ----------------------------------------------------------------
     115             :  */
     116             : 
     117             : /* ----------------
     118             :  *      index_open - open an index relation by relation OID
     119             :  *
     120             :  *      If lockmode is not "NoLock", the specified kind of lock is
     121             :  *      obtained on the index.  (Generally, NoLock should only be
     122             :  *      used if the caller knows it has some appropriate lock on the
     123             :  *      index already.)
     124             :  *
     125             :  *      An error is raised if the index does not exist.
     126             :  *
     127             :  *      This is a convenience routine adapted for indexscan use.
     128             :  *      Some callers may prefer to use relation_open directly.
     129             :  * ----------------
     130             :  */
     131             : Relation
     132    20652832 : index_open(Oid relationId, LOCKMODE lockmode)
     133             : {
     134             :     Relation    r;
     135             : 
     136    20652832 :     r = relation_open(relationId, lockmode);
     137             : 
     138    20652820 :     if (r->rd_rel->relkind != RELKIND_INDEX &&
     139        9458 :         r->rd_rel->relkind != RELKIND_PARTITIONED_INDEX)
     140          30 :         ereport(ERROR,
     141             :                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
     142             :                  errmsg("\"%s\" is not an index",
     143             :                         RelationGetRelationName(r))));
     144             : 
     145    20652790 :     return r;
     146             : }
     147             : 
     148             : /* ----------------
     149             :  *      index_close - close an index relation
     150             :  *
     151             :  *      If lockmode is not "NoLock", we then release the specified lock.
     152             :  *
     153             :  *      Note that it is often sensible to hold a lock beyond index_close;
     154             :  *      in that case, the lock is released automatically at xact end.
     155             :  * ----------------
     156             :  */
     157             : void
     158    20705394 : index_close(Relation relation, LOCKMODE lockmode)
     159             : {
     160    20705394 :     LockRelId   relid = relation->rd_lockInfo.lockRelId;
     161             : 
     162             :     Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
     163             : 
     164             :     /* The relcache does the real work... */
     165    20705394 :     RelationClose(relation);
     166             : 
     167    20705394 :     if (lockmode != NoLock)
     168    19235430 :         UnlockRelationId(&relid, lockmode);
     169    20705394 : }
     170             : 
     171             : /* ----------------
     172             :  *      index_insert - insert an index tuple into a relation
     173             :  * ----------------
     174             :  */
     175             : bool
     176    12559046 : index_insert(Relation indexRelation,
     177             :              Datum *values,
     178             :              bool *isnull,
     179             :              ItemPointer heap_t_ctid,
     180             :              Relation heapRelation,
     181             :              IndexUniqueCheck checkUnique,
     182             :              bool indexUnchanged,
     183             :              IndexInfo *indexInfo)
     184             : {
     185             :     RELATION_CHECKS;
     186    12559046 :     CHECK_REL_PROCEDURE(aminsert);
     187             : 
     188    12559046 :     if (!(indexRelation->rd_indam->ampredlocks))
     189      528590 :         CheckForSerializableConflictIn(indexRelation,
     190             :                                        (ItemPointer) NULL,
     191             :                                        InvalidBlockNumber);
     192             : 
     193    12559046 :     return indexRelation->rd_indam->aminsert(indexRelation, values, isnull,
     194             :                                              heap_t_ctid, heapRelation,
     195             :                                              checkUnique, indexUnchanged,
     196             :                                              indexInfo);
     197             : }
     198             : 
     199             : /*
     200             :  * index_beginscan - start a scan of an index with amgettuple
     201             :  *
     202             :  * Caller must be holding suitable locks on the heap and the index.
     203             :  */
     204             : IndexScanDesc
     205    13817314 : index_beginscan(Relation heapRelation,
     206             :                 Relation indexRelation,
     207             :                 Snapshot snapshot,
     208             :                 int nkeys, int norderbys)
     209             : {
     210             :     IndexScanDesc scan;
     211             : 
     212             :     Assert(snapshot != InvalidSnapshot);
     213             : 
     214    13817314 :     scan = index_beginscan_internal(indexRelation, nkeys, norderbys, snapshot, NULL, false);
     215             : 
     216             :     /*
     217             :      * Save additional parameters into the scandesc.  Everything else was set
     218             :      * up by RelationGetIndexScan.
     219             :      */
     220    13817314 :     scan->heapRelation = heapRelation;
     221    13817314 :     scan->xs_snapshot = snapshot;
     222             : 
     223             :     /* prepare to fetch index matches from table */
     224    13817314 :     scan->xs_heapfetch = table_index_fetch_begin(heapRelation);
     225             : 
     226    13817314 :     return scan;
     227             : }
     228             : 
     229             : /*
     230             :  * index_beginscan_bitmap - start a scan of an index with amgetbitmap
     231             :  *
     232             :  * As above, caller had better be holding some lock on the parent heap
     233             :  * relation, even though it's not explicitly mentioned here.
     234             :  */
     235             : IndexScanDesc
     236       17458 : index_beginscan_bitmap(Relation indexRelation,
     237             :                        Snapshot snapshot,
     238             :                        int nkeys)
     239             : {
     240             :     IndexScanDesc scan;
     241             : 
     242             :     Assert(snapshot != InvalidSnapshot);
     243             : 
     244       17458 :     scan = index_beginscan_internal(indexRelation, nkeys, 0, snapshot, NULL, false);
     245             : 
     246             :     /*
     247             :      * Save additional parameters into the scandesc.  Everything else was set
     248             :      * up by RelationGetIndexScan.
     249             :      */
     250       17458 :     scan->xs_snapshot = snapshot;
     251             : 
     252       17458 :     return scan;
     253             : }
     254             : 
     255             : /*
     256             :  * index_beginscan_internal --- common code for index_beginscan variants
     257             :  */
     258             : static IndexScanDesc
     259    13835108 : index_beginscan_internal(Relation indexRelation,
     260             :                          int nkeys, int norderbys, Snapshot snapshot,
     261             :                          ParallelIndexScanDesc pscan, bool temp_snap)
     262             : {
     263             :     IndexScanDesc scan;
     264             : 
     265             :     RELATION_CHECKS;
     266    13835108 :     CHECK_REL_PROCEDURE(ambeginscan);
     267             : 
     268    13835108 :     if (!(indexRelation->rd_indam->ampredlocks))
     269        4246 :         PredicateLockRelation(indexRelation, snapshot);
     270             : 
     271             :     /*
     272             :      * We hold a reference count to the relcache entry throughout the scan.
     273             :      */
     274    13835108 :     RelationIncrementReferenceCount(indexRelation);
     275             : 
     276             :     /*
     277             :      * Tell the AM to open a scan.
     278             :      */
     279    13835108 :     scan = indexRelation->rd_indam->ambeginscan(indexRelation, nkeys,
     280             :                                                 norderbys);
     281             :     /* Initialize information for parallel scan. */
     282    13835108 :     scan->parallel_scan = pscan;
     283    13835108 :     scan->xs_temp_snap = temp_snap;
     284             : 
     285    13835108 :     return scan;
     286             : }
     287             : 
     288             : /* ----------------
     289             :  *      index_rescan  - (re)start a scan of an index
     290             :  *
     291             :  * During a restart, the caller may specify a new set of scankeys and/or
     292             :  * orderbykeys; but the number of keys cannot differ from what index_beginscan
     293             :  * was told.  (Later we might relax that to "must not exceed", but currently
     294             :  * the index AMs tend to assume that scan->numberOfKeys is what to believe.)
     295             :  * To restart the scan without changing keys, pass NULL for the key arrays.
     296             :  * (Of course, keys *must* be passed on the first call, unless
     297             :  * scan->numberOfKeys is zero.)
     298             :  * ----------------
     299             :  */
     300             : void
     301    14189530 : index_rescan(IndexScanDesc scan,
     302             :              ScanKey keys, int nkeys,
     303             :              ScanKey orderbys, int norderbys)
     304             : {
     305             :     SCAN_CHECKS;
     306    14189530 :     CHECK_SCAN_PROCEDURE(amrescan);
     307             : 
     308             :     Assert(nkeys == scan->numberOfKeys);
     309             :     Assert(norderbys == scan->numberOfOrderBys);
     310             : 
     311             :     /* Release resources (like buffer pins) from table accesses */
     312    14189530 :     if (scan->xs_heapfetch)
     313    14169210 :         table_index_fetch_reset(scan->xs_heapfetch);
     314             : 
     315    14189530 :     scan->kill_prior_tuple = false; /* for safety */
     316    14189530 :     scan->xs_heap_continue = false;
     317             : 
     318    14189530 :     scan->indexRelation->rd_indam->amrescan(scan, keys, nkeys,
     319             :                                             orderbys, norderbys);
     320    14189530 : }
     321             : 
     322             : /* ----------------
     323             :  *      index_endscan - end a scan
     324             :  * ----------------
     325             :  */
     326             : void
     327    13833732 : index_endscan(IndexScanDesc scan)
     328             : {
     329             :     SCAN_CHECKS;
     330    13833732 :     CHECK_SCAN_PROCEDURE(amendscan);
     331             : 
     332             :     /* Release resources (like buffer pins) from table accesses */
     333    13833732 :     if (scan->xs_heapfetch)
     334             :     {
     335    13816340 :         table_index_fetch_end(scan->xs_heapfetch);
     336    13816340 :         scan->xs_heapfetch = NULL;
     337             :     }
     338             : 
     339             :     /* End the AM's scan */
     340    13833732 :     scan->indexRelation->rd_indam->amendscan(scan);
     341             : 
     342             :     /* Release index refcount acquired by index_beginscan */
     343    13833732 :     RelationDecrementReferenceCount(scan->indexRelation);
     344             : 
     345    13833732 :     if (scan->xs_temp_snap)
     346         336 :         UnregisterSnapshot(scan->xs_snapshot);
     347             : 
     348             :     /* Release the scan data structure itself */
     349    13833732 :     IndexScanEnd(scan);
     350    13833732 : }
     351             : 
     352             : /* ----------------
     353             :  *      index_markpos  - mark a scan position
     354             :  * ----------------
     355             :  */
     356             : void
     357      130058 : index_markpos(IndexScanDesc scan)
     358             : {
     359             :     SCAN_CHECKS;
     360      130058 :     CHECK_SCAN_PROCEDURE(ammarkpos);
     361             : 
     362      130058 :     scan->indexRelation->rd_indam->ammarkpos(scan);
     363      130058 : }
     364             : 
     365             : /* ----------------
     366             :  *      index_restrpos  - restore a scan position
     367             :  *
     368             :  * NOTE: this only restores the internal scan state of the index AM.  See
     369             :  * comments for ExecRestrPos().
     370             :  *
     371             :  * NOTE: For heap, in the presence of HOT chains, mark/restore only works
     372             :  * correctly if the scan's snapshot is MVCC-safe; that ensures that there's at
     373             :  * most one returnable tuple in each HOT chain, and so restoring the prior
     374             :  * state at the granularity of the index AM is sufficient.  Since the only
     375             :  * current user of mark/restore functionality is nodeMergejoin.c, this
     376             :  * effectively means that merge-join plans only work for MVCC snapshots.  This
     377             :  * could be fixed if necessary, but for now it seems unimportant.
     378             :  * ----------------
     379             :  */
     380             : void
     381       54030 : index_restrpos(IndexScanDesc scan)
     382             : {
     383             :     Assert(IsMVCCSnapshot(scan->xs_snapshot));
     384             : 
     385             :     SCAN_CHECKS;
     386       54030 :     CHECK_SCAN_PROCEDURE(amrestrpos);
     387             : 
     388             :     /* release resources (like buffer pins) from table accesses */
     389       54030 :     if (scan->xs_heapfetch)
     390       54030 :         table_index_fetch_reset(scan->xs_heapfetch);
     391             : 
     392       54030 :     scan->kill_prior_tuple = false; /* for safety */
     393       54030 :     scan->xs_heap_continue = false;
     394             : 
     395       54030 :     scan->indexRelation->rd_indam->amrestrpos(scan);
     396       54030 : }
     397             : 
     398             : /*
     399             :  * index_parallelscan_estimate - estimate shared memory for parallel scan
     400             :  *
     401             :  * Currently, we don't pass any information to the AM-specific estimator,
     402             :  * so it can probably only return a constant.  In the future, we might need
     403             :  * to pass more information.
     404             :  */
     405             : Size
     406          48 : index_parallelscan_estimate(Relation indexRelation, Snapshot snapshot)
     407             : {
     408             :     Size        nbytes;
     409             : 
     410             :     Assert(snapshot != InvalidSnapshot);
     411             : 
     412             :     RELATION_CHECKS;
     413             : 
     414          48 :     nbytes = offsetof(ParallelIndexScanDescData, ps_snapshot_data);
     415          48 :     nbytes = add_size(nbytes, EstimateSnapshotSpace(snapshot));
     416          48 :     nbytes = MAXALIGN(nbytes);
     417             : 
     418             :     /*
     419             :      * If amestimateparallelscan is not provided, assume there is no
     420             :      * AM-specific data needed.  (It's hard to believe that could work, but
     421             :      * it's easy enough to cater to it here.)
     422             :      */
     423          48 :     if (indexRelation->rd_indam->amestimateparallelscan != NULL)
     424          48 :         nbytes = add_size(nbytes,
     425          48 :                           indexRelation->rd_indam->amestimateparallelscan());
     426             : 
     427          48 :     return nbytes;
     428             : }
     429             : 
     430             : /*
     431             :  * index_parallelscan_initialize - initialize parallel scan
     432             :  *
     433             :  * We initialize both the ParallelIndexScanDesc proper and the AM-specific
     434             :  * information which follows it.
     435             :  *
     436             :  * This function calls access method specific initialization routine to
     437             :  * initialize am specific information.  Call this just once in the leader
     438             :  * process; then, individual workers attach via index_beginscan_parallel.
     439             :  */
     440             : void
     441          48 : index_parallelscan_initialize(Relation heapRelation, Relation indexRelation,
     442             :                               Snapshot snapshot, ParallelIndexScanDesc target)
     443             : {
     444             :     Size        offset;
     445             : 
     446             :     Assert(snapshot != InvalidSnapshot);
     447             : 
     448             :     RELATION_CHECKS;
     449             : 
     450          48 :     offset = add_size(offsetof(ParallelIndexScanDescData, ps_snapshot_data),
     451             :                       EstimateSnapshotSpace(snapshot));
     452          48 :     offset = MAXALIGN(offset);
     453             : 
     454          48 :     target->ps_relid = RelationGetRelid(heapRelation);
     455          48 :     target->ps_indexid = RelationGetRelid(indexRelation);
     456          48 :     target->ps_offset = offset;
     457          48 :     SerializeSnapshot(snapshot, target->ps_snapshot_data);
     458             : 
     459             :     /* aminitparallelscan is optional; assume no-op if not provided by AM */
     460          48 :     if (indexRelation->rd_indam->aminitparallelscan != NULL)
     461             :     {
     462             :         void       *amtarget;
     463             : 
     464          48 :         amtarget = OffsetToPointer(target, offset);
     465          48 :         indexRelation->rd_indam->aminitparallelscan(amtarget);
     466             :     }
     467          48 : }
     468             : 
     469             : /* ----------------
     470             :  *      index_parallelrescan  - (re)start a parallel scan of an index
     471             :  * ----------------
     472             :  */
     473             : void
     474          24 : index_parallelrescan(IndexScanDesc scan)
     475             : {
     476             :     SCAN_CHECKS;
     477             : 
     478          24 :     if (scan->xs_heapfetch)
     479          24 :         table_index_fetch_reset(scan->xs_heapfetch);
     480             : 
     481             :     /* amparallelrescan is optional; assume no-op if not provided by AM */
     482          24 :     if (scan->indexRelation->rd_indam->amparallelrescan != NULL)
     483          24 :         scan->indexRelation->rd_indam->amparallelrescan(scan);
     484          24 : }
     485             : 
     486             : /*
     487             :  * index_beginscan_parallel - join parallel index scan
     488             :  *
     489             :  * Caller must be holding suitable locks on the heap and the index.
     490             :  */
     491             : IndexScanDesc
     492         336 : index_beginscan_parallel(Relation heaprel, Relation indexrel, int nkeys,
     493             :                          int norderbys, ParallelIndexScanDesc pscan)
     494             : {
     495             :     Snapshot    snapshot;
     496             :     IndexScanDesc scan;
     497             : 
     498             :     Assert(RelationGetRelid(heaprel) == pscan->ps_relid);
     499         336 :     snapshot = RestoreSnapshot(pscan->ps_snapshot_data);
     500         336 :     RegisterSnapshot(snapshot);
     501         336 :     scan = index_beginscan_internal(indexrel, nkeys, norderbys, snapshot,
     502             :                                     pscan, true);
     503             : 
     504             :     /*
     505             :      * Save additional parameters into the scandesc.  Everything else was set
     506             :      * up by index_beginscan_internal.
     507             :      */
     508         336 :     scan->heapRelation = heaprel;
     509         336 :     scan->xs_snapshot = snapshot;
     510             : 
     511             :     /* prepare to fetch index matches from table */
     512         336 :     scan->xs_heapfetch = table_index_fetch_begin(heaprel);
     513             : 
     514         336 :     return scan;
     515             : }
     516             : 
     517             : /* ----------------
     518             :  * index_getnext_tid - get the next TID from a scan
     519             :  *
     520             :  * The result is the next TID satisfying the scan keys,
     521             :  * or NULL if no more matching tuples exist.
     522             :  * ----------------
     523             :  */
     524             : ItemPointer
     525    38278864 : index_getnext_tid(IndexScanDesc scan, ScanDirection direction)
     526             : {
     527             :     bool        found;
     528             : 
     529             :     SCAN_CHECKS;
     530    38278864 :     CHECK_SCAN_PROCEDURE(amgettuple);
     531             : 
     532             :     /* XXX: we should assert that a snapshot is pushed or registered */
     533             :     Assert(TransactionIdIsValid(RecentXmin));
     534             : 
     535             :     /*
     536             :      * The AM's amgettuple proc finds the next index entry matching the scan
     537             :      * keys, and puts the TID into scan->xs_heaptid.  It should also set
     538             :      * scan->xs_recheck and possibly scan->xs_itup/scan->xs_hitup, though we
     539             :      * pay no attention to those fields here.
     540             :      */
     541    38278864 :     found = scan->indexRelation->rd_indam->amgettuple(scan, direction);
     542             : 
     543             :     /* Reset kill flag immediately for safety */
     544    38278862 :     scan->kill_prior_tuple = false;
     545    38278862 :     scan->xs_heap_continue = false;
     546             : 
     547             :     /* If we're out of index entries, we're done */
     548    38278862 :     if (!found)
     549             :     {
     550             :         /* release resources (like buffer pins) from table accesses */
     551     6938336 :         if (scan->xs_heapfetch)
     552     6938336 :             table_index_fetch_reset(scan->xs_heapfetch);
     553             : 
     554     6938336 :         return NULL;
     555             :     }
     556             :     Assert(ItemPointerIsValid(&scan->xs_heaptid));
     557             : 
     558    31340526 :     pgstat_count_index_tuples(scan->indexRelation, 1);
     559             : 
     560             :     /* Return the TID of the tuple we found. */
     561    31340526 :     return &scan->xs_heaptid;
     562             : }
     563             : 
     564             : /* ----------------
     565             :  *      index_fetch_heap - get the scan's next heap tuple
     566             :  *
     567             :  * The result is a visible heap tuple associated with the index TID most
     568             :  * recently fetched by index_getnext_tid, or NULL if no more matching tuples
     569             :  * exist.  (There can be more than one matching tuple because of HOT chains,
     570             :  * although when using an MVCC snapshot it should be impossible for more than
     571             :  * one such tuple to exist.)
     572             :  *
     573             :  * On success, the buffer containing the heap tup is pinned (the pin will be
     574             :  * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
     575             :  * call).
     576             :  *
     577             :  * Note: caller must check scan->xs_recheck, and perform rechecking of the
     578             :  * scan keys if required.  We do not do that here because we don't have
     579             :  * enough information to do it efficiently in the general case.
     580             :  * ----------------
     581             :  */
     582             : bool
     583    28640126 : index_fetch_heap(IndexScanDesc scan, TupleTableSlot *slot)
     584             : {
     585    28640126 :     bool        all_dead = false;
     586             :     bool        found;
     587             : 
     588    28640126 :     found = table_index_fetch_tuple(scan->xs_heapfetch, &scan->xs_heaptid,
     589             :                                     scan->xs_snapshot, slot,
     590             :                                     &scan->xs_heap_continue, &all_dead);
     591             : 
     592    28640116 :     if (found)
     593    27503812 :         pgstat_count_heap_fetch(scan->indexRelation);
     594             : 
     595             :     /*
     596             :      * If we scanned a whole HOT chain and found only dead tuples, tell index
     597             :      * AM to kill its entry for that TID (this will take effect in the next
     598             :      * amgettuple call, in index_getnext_tid).  We do not do this when in
     599             :      * recovery because it may violate MVCC to do so.  See comments in
     600             :      * RelationGetIndexScan().
     601             :      */
     602    28640116 :     if (!scan->xactStartedInRecovery)
     603    28421960 :         scan->kill_prior_tuple = all_dead;
     604             : 
     605    28640116 :     return found;
     606             : }
     607             : 
     608             : /* ----------------
     609             :  *      index_getnext_slot - get the next tuple from a scan
     610             :  *
     611             :  * The result is true if a tuple satisfying the scan keys and the snapshot was
     612             :  * found, false otherwise.  The tuple is stored in the specified slot.
     613             :  *
     614             :  * On success, resources (like buffer pins) are likely to be held, and will be
     615             :  * dropped by a future index_getnext_tid, index_fetch_heap or index_endscan
     616             :  * call).
     617             :  *
     618             :  * Note: caller must check scan->xs_recheck, and perform rechecking of the
     619             :  * scan keys if required.  We do not do that here because we don't have
     620             :  * enough information to do it efficiently in the general case.
     621             :  * ----------------
     622             :  */
     623             : bool
     624    33674494 : index_getnext_slot(IndexScanDesc scan, ScanDirection direction, TupleTableSlot *slot)
     625             : {
     626             :     for (;;)
     627             :     {
     628    33674494 :         if (!scan->xs_heap_continue)
     629             :         {
     630             :             ItemPointer tid;
     631             : 
     632             :             /* Time to fetch the next TID from the index */
     633    33349716 :             tid = index_getnext_tid(scan, direction);
     634             : 
     635             :             /* If we're out of index entries, we're done */
     636    33349714 :             if (tid == NULL)
     637     6858720 :                 break;
     638             : 
     639             :             Assert(ItemPointerEquals(tid, &scan->xs_heaptid));
     640             :         }
     641             : 
     642             :         /*
     643             :          * Fetch the next (or only) visible heap tuple for this index entry.
     644             :          * If we don't find anything, loop around and grab the next TID from
     645             :          * the index.
     646             :          */
     647             :         Assert(ItemPointerIsValid(&scan->xs_heaptid));
     648    26815772 :         if (index_fetch_heap(scan, slot))
     649    25759454 :             return true;
     650             :     }
     651             : 
     652     6858720 :     return false;
     653             : }
     654             : 
     655             : /* ----------------
     656             :  *      index_getbitmap - get all tuples at once from an index scan
     657             :  *
     658             :  * Adds the TIDs of all heap tuples satisfying the scan keys to a bitmap.
     659             :  * Since there's no interlock between the index scan and the eventual heap
     660             :  * access, this is only safe to use with MVCC-based snapshots: the heap
     661             :  * item slot could have been replaced by a newer tuple by the time we get
     662             :  * to it.
     663             :  *
     664             :  * Returns the number of matching tuples found.  (Note: this might be only
     665             :  * approximate, so it should only be used for statistical purposes.)
     666             :  * ----------------
     667             :  */
     668             : int64
     669       17024 : index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap)
     670             : {
     671             :     int64       ntids;
     672             : 
     673             :     SCAN_CHECKS;
     674       17024 :     CHECK_SCAN_PROCEDURE(amgetbitmap);
     675             : 
     676             :     /* just make sure this is false... */
     677       17024 :     scan->kill_prior_tuple = false;
     678             : 
     679             :     /*
     680             :      * have the am's getbitmap proc do all the work.
     681             :      */
     682       17024 :     ntids = scan->indexRelation->rd_indam->amgetbitmap(scan, bitmap);
     683             : 
     684       17024 :     pgstat_count_index_tuples(scan->indexRelation, ntids);
     685             : 
     686       17024 :     return ntids;
     687             : }
     688             : 
     689             : /* ----------------
     690             :  *      index_bulk_delete - do mass deletion of index entries
     691             :  *
     692             :  *      callback routine tells whether a given main-heap tuple is
     693             :  *      to be deleted
     694             :  *
     695             :  *      return value is an optional palloc'd struct of statistics
     696             :  * ----------------
     697             :  */
     698             : IndexBulkDeleteResult *
     699        7716 : index_bulk_delete(IndexVacuumInfo *info,
     700             :                   IndexBulkDeleteResult *istat,
     701             :                   IndexBulkDeleteCallback callback,
     702             :                   void *callback_state)
     703             : {
     704        7716 :     Relation    indexRelation = info->index;
     705             : 
     706             :     RELATION_CHECKS;
     707        7716 :     CHECK_REL_PROCEDURE(ambulkdelete);
     708             : 
     709        7716 :     return indexRelation->rd_indam->ambulkdelete(info, istat,
     710             :                                                  callback, callback_state);
     711             : }
     712             : 
     713             : /* ----------------
     714             :  *      index_vacuum_cleanup - do post-deletion cleanup of an index
     715             :  *
     716             :  *      return value is an optional palloc'd struct of statistics
     717             :  * ----------------
     718             :  */
     719             : IndexBulkDeleteResult *
     720      178004 : index_vacuum_cleanup(IndexVacuumInfo *info,
     721             :                      IndexBulkDeleteResult *istat)
     722             : {
     723      178004 :     Relation    indexRelation = info->index;
     724             : 
     725             :     RELATION_CHECKS;
     726      178004 :     CHECK_REL_PROCEDURE(amvacuumcleanup);
     727             : 
     728      178004 :     return indexRelation->rd_indam->amvacuumcleanup(info, istat);
     729             : }
     730             : 
     731             : /* ----------------
     732             :  *      index_can_return
     733             :  *
     734             :  *      Does the index access method support index-only scans for the given
     735             :  *      column?
     736             :  * ----------------
     737             :  */
     738             : bool
     739     1037286 : index_can_return(Relation indexRelation, int attno)
     740             : {
     741             :     RELATION_CHECKS;
     742             : 
     743             :     /* amcanreturn is optional; assume false if not provided by AM */
     744     1037286 :     if (indexRelation->rd_indam->amcanreturn == NULL)
     745      272098 :         return false;
     746             : 
     747      765188 :     return indexRelation->rd_indam->amcanreturn(indexRelation, attno);
     748             : }
     749             : 
     750             : /* ----------------
     751             :  *      index_getprocid
     752             :  *
     753             :  *      Index access methods typically require support routines that are
     754             :  *      not directly the implementation of any WHERE-clause query operator
     755             :  *      and so cannot be kept in pg_amop.  Instead, such routines are kept
     756             :  *      in pg_amproc.  These registered procedure OIDs are assigned numbers
     757             :  *      according to a convention established by the access method.
     758             :  *      The general index code doesn't know anything about the routines
     759             :  *      involved; it just builds an ordered list of them for
     760             :  *      each attribute on which an index is defined.
     761             :  *
     762             :  *      As of Postgres 8.3, support routines within an operator family
     763             :  *      are further subdivided by the "left type" and "right type" of the
     764             :  *      query operator(s) that they support.  The "default" functions for a
     765             :  *      particular indexed attribute are those with both types equal to
     766             :  *      the index opclass' opcintype (note that this is subtly different
     767             :  *      from the indexed attribute's own type: it may be a binary-compatible
     768             :  *      type instead).  Only the default functions are stored in relcache
     769             :  *      entries --- access methods can use the syscache to look up non-default
     770             :  *      functions.
     771             :  *
     772             :  *      This routine returns the requested default procedure OID for a
     773             :  *      particular indexed attribute.
     774             :  * ----------------
     775             :  */
     776             : RegProcedure
     777    13836988 : index_getprocid(Relation irel,
     778             :                 AttrNumber attnum,
     779             :                 uint16 procnum)
     780             : {
     781             :     RegProcedure *loc;
     782             :     int         nproc;
     783             :     int         procindex;
     784             : 
     785    13836988 :     nproc = irel->rd_indam->amsupport;
     786             : 
     787             :     Assert(procnum > 0 && procnum <= (uint16) nproc);
     788             : 
     789    13836988 :     procindex = (nproc * (attnum - 1)) + (procnum - 1);
     790             : 
     791    13836988 :     loc = irel->rd_support;
     792             : 
     793             :     Assert(loc != NULL);
     794             : 
     795    13836988 :     return loc[procindex];
     796             : }
     797             : 
     798             : /* ----------------
     799             :  *      index_getprocinfo
     800             :  *
     801             :  *      This routine allows index AMs to keep fmgr lookup info for
     802             :  *      support procs in the relcache.  As above, only the "default"
     803             :  *      functions for any particular indexed attribute are cached.
     804             :  *
     805             :  * Note: the return value points into cached data that will be lost during
     806             :  * any relcache rebuild!  Therefore, either use the callinfo right away,
     807             :  * or save it only after having acquired some type of lock on the index rel.
     808             :  * ----------------
     809             :  */
     810             : FmgrInfo *
     811    54912004 : index_getprocinfo(Relation irel,
     812             :                   AttrNumber attnum,
     813             :                   uint16 procnum)
     814             : {
     815             :     FmgrInfo   *locinfo;
     816             :     int         nproc;
     817             :     int         optsproc;
     818             :     int         procindex;
     819             : 
     820    54912004 :     nproc = irel->rd_indam->amsupport;
     821    54912004 :     optsproc = irel->rd_indam->amoptsprocnum;
     822             : 
     823             :     Assert(procnum > 0 && procnum <= (uint16) nproc);
     824             : 
     825    54912004 :     procindex = (nproc * (attnum - 1)) + (procnum - 1);
     826             : 
     827    54912004 :     locinfo = irel->rd_supportinfo;
     828             : 
     829             :     Assert(locinfo != NULL);
     830             : 
     831    54912004 :     locinfo += procindex;
     832             : 
     833             :     /* Initialize the lookup info if first time through */
     834    54912004 :     if (locinfo->fn_oid == InvalidOid)
     835             :     {
     836      970220 :         RegProcedure *loc = irel->rd_support;
     837             :         RegProcedure procId;
     838             : 
     839             :         Assert(loc != NULL);
     840             : 
     841      970220 :         procId = loc[procindex];
     842             : 
     843             :         /*
     844             :          * Complain if function was not found during IndexSupportInitialize.
     845             :          * This should not happen unless the system tables contain bogus
     846             :          * entries for the index opclass.  (If an AM wants to allow a support
     847             :          * function to be optional, it can use index_getprocid.)
     848             :          */
     849      970220 :         if (!RegProcedureIsValid(procId))
     850           0 :             elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
     851             :                  procnum, attnum, RelationGetRelationName(irel));
     852             : 
     853      970220 :         fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
     854             : 
     855      970220 :         if (procnum != optsproc)
     856             :         {
     857             :             /* Initialize locinfo->fn_expr with opclass options Const */
     858      968474 :             bytea     **attoptions = RelationGetIndexAttOptions(irel, false);
     859      968474 :             MemoryContext oldcxt = MemoryContextSwitchTo(irel->rd_indexcxt);
     860             : 
     861      968474 :             set_fn_opclass_options(locinfo, attoptions[attnum - 1]);
     862             : 
     863      968474 :             MemoryContextSwitchTo(oldcxt);
     864             :         }
     865             :     }
     866             : 
     867    54912004 :     return locinfo;
     868             : }
     869             : 
     870             : /* ----------------
     871             :  *      index_store_float8_orderby_distances
     872             :  *
     873             :  *      Convert AM distance function's results (that can be inexact)
     874             :  *      to ORDER BY types and save them into xs_orderbyvals/xs_orderbynulls
     875             :  *      for a possible recheck.
     876             :  * ----------------
     877             :  */
     878             : void
     879      364600 : index_store_float8_orderby_distances(IndexScanDesc scan, Oid *orderByTypes,
     880             :                                      IndexOrderByDistance *distances,
     881             :                                      bool recheckOrderBy)
     882             : {
     883             :     int         i;
     884             : 
     885             :     Assert(distances || !recheckOrderBy);
     886             : 
     887      364600 :     scan->xs_recheckorderby = recheckOrderBy;
     888             : 
     889      729218 :     for (i = 0; i < scan->numberOfOrderBys; i++)
     890             :     {
     891      364618 :         if (orderByTypes[i] == FLOAT8OID)
     892             :         {
     893             : #ifndef USE_FLOAT8_BYVAL
     894             :             /* must free any old value to avoid memory leakage */
     895             :             if (!scan->xs_orderbynulls[i])
     896             :                 pfree(DatumGetPointer(scan->xs_orderbyvals[i]));
     897             : #endif
     898      364488 :             if (distances && !distances[i].isnull)
     899             :             {
     900      364428 :                 scan->xs_orderbyvals[i] = Float8GetDatum(distances[i].value);
     901      364428 :                 scan->xs_orderbynulls[i] = false;
     902             :             }
     903             :             else
     904             :             {
     905          60 :                 scan->xs_orderbyvals[i] = (Datum) 0;
     906          60 :                 scan->xs_orderbynulls[i] = true;
     907             :             }
     908             :         }
     909         130 :         else if (orderByTypes[i] == FLOAT4OID)
     910             :         {
     911             :             /* convert distance function's result to ORDER BY type */
     912          70 :             if (distances && !distances[i].isnull)
     913             :             {
     914          70 :                 scan->xs_orderbyvals[i] = Float4GetDatum((float4) distances[i].value);
     915          70 :                 scan->xs_orderbynulls[i] = false;
     916             :             }
     917             :             else
     918             :             {
     919           0 :                 scan->xs_orderbyvals[i] = (Datum) 0;
     920           0 :                 scan->xs_orderbynulls[i] = true;
     921             :             }
     922             :         }
     923             :         else
     924             :         {
     925             :             /*
     926             :              * If the ordering operator's return value is anything else, we
     927             :              * don't know how to convert the float8 bound calculated by the
     928             :              * distance function to that.  The executor won't actually need
     929             :              * the order by values we return here, if there are no lossy
     930             :              * results, so only insist on converting if the *recheck flag is
     931             :              * set.
     932             :              */
     933          60 :             if (scan->xs_recheckorderby)
     934           0 :                 elog(ERROR, "ORDER BY operator must return float8 or float4 if the distance function is lossy");
     935          60 :             scan->xs_orderbynulls[i] = true;
     936             :         }
     937             :     }
     938      364600 : }
     939             : 
     940             : /* ----------------
     941             :  *      index_opclass_options
     942             :  *
     943             :  *      Parse opclass-specific options for index column.
     944             :  * ----------------
     945             :  */
     946             : bytea *
     947      740350 : index_opclass_options(Relation indrel, AttrNumber attnum, Datum attoptions,
     948             :                       bool validate)
     949             : {
     950      740350 :     int         amoptsprocnum = indrel->rd_indam->amoptsprocnum;
     951      740350 :     Oid         procid = InvalidOid;
     952             :     FmgrInfo   *procinfo;
     953             :     local_relopts relopts;
     954             : 
     955             :     /* fetch options support procedure if specified */
     956      740350 :     if (amoptsprocnum != 0)
     957      740294 :         procid = index_getprocid(indrel, attnum, amoptsprocnum);
     958             : 
     959      740350 :     if (!OidIsValid(procid))
     960             :     {
     961             :         Oid         opclass;
     962             :         Datum       indclassDatum;
     963             :         oidvector  *indclass;
     964             :         bool        isnull;
     965             : 
     966      738448 :         if (!DatumGetPointer(attoptions))
     967      738442 :             return NULL;        /* ok, no options, no procedure */
     968             : 
     969             :         /*
     970             :          * Report an error if the opclass's options-parsing procedure does not
     971             :          * exist but the opclass options are specified.
     972             :          */
     973           6 :         indclassDatum = SysCacheGetAttr(INDEXRELID, indrel->rd_indextuple,
     974             :                                         Anum_pg_index_indclass, &isnull);
     975             :         Assert(!isnull);
     976           6 :         indclass = (oidvector *) DatumGetPointer(indclassDatum);
     977           6 :         opclass = indclass->values[attnum - 1];
     978             : 
     979           6 :         ereport(ERROR,
     980             :                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
     981             :                  errmsg("operator class %s has no options",
     982             :                         generate_opclass_name(opclass))));
     983             :     }
     984             : 
     985        1902 :     init_local_reloptions(&relopts, 0);
     986             : 
     987        1902 :     procinfo = index_getprocinfo(indrel, attnum, amoptsprocnum);
     988             : 
     989        1902 :     (void) FunctionCall1(procinfo, PointerGetDatum(&relopts));
     990             : 
     991        1902 :     return build_local_reloptions(&relopts, attoptions, validate);
     992             : }

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