LCOV - code coverage report
Current view: top level - src/backend/access/index - indexam.c (source / functions) Hit Total Coverage
Test: PostgreSQL 17beta1 Lines: 219 224 97.8 %
Date: 2024-06-14 19:10:57 Functions: 28 28 100.0 %
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) 1996-2024, 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/relation.h"
      48             : #include "access/reloptions.h"
      49             : #include "access/relscan.h"
      50             : #include "access/tableam.h"
      51             : #include "catalog/index.h"
      52             : #include "catalog/pg_type.h"
      53             : #include "nodes/execnodes.h"
      54             : #include "pgstat.h"
      55             : #include "storage/lmgr.h"
      56             : #include "storage/predicate.h"
      57             : #include "utils/ruleutils.h"
      58             : #include "utils/snapmgr.h"
      59             : #include "utils/syscache.h"
      60             : 
      61             : 
      62             : /* ----------------------------------------------------------------
      63             :  *                  macros used in index_ routines
      64             :  *
      65             :  * Note: the ReindexIsProcessingIndex() check in RELATION_CHECKS is there
      66             :  * to check that we don't try to scan or do retail insertions into an index
      67             :  * that is currently being rebuilt or pending rebuild.  This helps to catch
      68             :  * things that don't work when reindexing system catalogs, as well as prevent
      69             :  * user errors like index expressions that access their own tables.  The check
      70             :  * doesn't prevent the actual rebuild because we don't use RELATION_CHECKS
      71             :  * when calling the index AM's ambuild routine, and there is no reason for
      72             :  * ambuild to call its subsidiary routines through this file.
      73             :  * ----------------------------------------------------------------
      74             :  */
      75             : #define RELATION_CHECKS \
      76             : do { \
      77             :     Assert(RelationIsValid(indexRelation)); \
      78             :     Assert(PointerIsValid(indexRelation->rd_indam)); \
      79             :     if (unlikely(ReindexIsProcessingIndex(RelationGetRelid(indexRelation)))) \
      80             :         ereport(ERROR, \
      81             :                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), \
      82             :                  errmsg("cannot access index \"%s\" while it is being reindexed", \
      83             :                         RelationGetRelationName(indexRelation)))); \
      84             : } while(0)
      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             : static inline void validate_relation_kind(Relation r);
     111             : 
     112             : 
     113             : /* ----------------------------------------------------------------
     114             :  *                 index_ interface functions
     115             :  * ----------------------------------------------------------------
     116             :  */
     117             : 
     118             : /* ----------------
     119             :  *      index_open - open an index relation by relation OID
     120             :  *
     121             :  *      If lockmode is not "NoLock", the specified kind of lock is
     122             :  *      obtained on the index.  (Generally, NoLock should only be
     123             :  *      used if the caller knows it has some appropriate lock on the
     124             :  *      index already.)
     125             :  *
     126             :  *      An error is raised if the index does not exist.
     127             :  *
     128             :  *      This is a convenience routine adapted for indexscan use.
     129             :  *      Some callers may prefer to use relation_open directly.
     130             :  * ----------------
     131             :  */
     132             : Relation
     133    14313236 : index_open(Oid relationId, LOCKMODE lockmode)
     134             : {
     135             :     Relation    r;
     136             : 
     137    14313236 :     r = relation_open(relationId, lockmode);
     138             : 
     139    14313220 :     validate_relation_kind(r);
     140             : 
     141    14313198 :     return r;
     142             : }
     143             : 
     144             : /* ----------------
     145             :  *      try_index_open - open an index relation by relation OID
     146             :  *
     147             :  *      Same as index_open, except return NULL instead of failing
     148             :  *      if the relation does not exist.
     149             :  * ----------------
     150             :  */
     151             : Relation
     152        2132 : try_index_open(Oid relationId, LOCKMODE lockmode)
     153             : {
     154             :     Relation    r;
     155             : 
     156        2132 :     r = try_relation_open(relationId, lockmode);
     157             : 
     158             :     /* leave if index does not exist */
     159        2132 :     if (!r)
     160           0 :         return NULL;
     161             : 
     162        2132 :     validate_relation_kind(r);
     163             : 
     164        2132 :     return r;
     165             : }
     166             : 
     167             : /* ----------------
     168             :  *      index_close - close an index relation
     169             :  *
     170             :  *      If lockmode is not "NoLock", we then release the specified lock.
     171             :  *
     172             :  *      Note that it is often sensible to hold a lock beyond index_close;
     173             :  *      in that case, the lock is released automatically at xact end.
     174             :  * ----------------
     175             :  */
     176             : void
     177    14345172 : index_close(Relation relation, LOCKMODE lockmode)
     178             : {
     179    14345172 :     LockRelId   relid = relation->rd_lockInfo.lockRelId;
     180             : 
     181             :     Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
     182             : 
     183             :     /* The relcache does the real work... */
     184    14345172 :     RelationClose(relation);
     185             : 
     186    14345172 :     if (lockmode != NoLock)
     187    13155008 :         UnlockRelationId(&relid, lockmode);
     188    14345172 : }
     189             : 
     190             : /* ----------------
     191             :  *      validate_relation_kind - check the relation's kind
     192             :  *
     193             :  *      Make sure relkind is an index or a partitioned index.
     194             :  * ----------------
     195             :  */
     196             : static inline void
     197    14315352 : validate_relation_kind(Relation r)
     198             : {
     199    14315352 :     if (r->rd_rel->relkind != RELKIND_INDEX &&
     200       10756 :         r->rd_rel->relkind != RELKIND_PARTITIONED_INDEX)
     201          22 :         ereport(ERROR,
     202             :                 (errcode(ERRCODE_WRONG_OBJECT_TYPE),
     203             :                  errmsg("\"%s\" is not an index",
     204             :                         RelationGetRelationName(r))));
     205    14315330 : }
     206             : 
     207             : 
     208             : /* ----------------
     209             :  *      index_insert - insert an index tuple into a relation
     210             :  * ----------------
     211             :  */
     212             : bool
     213     7554712 : index_insert(Relation indexRelation,
     214             :              Datum *values,
     215             :              bool *isnull,
     216             :              ItemPointer heap_t_ctid,
     217             :              Relation heapRelation,
     218             :              IndexUniqueCheck checkUnique,
     219             :              bool indexUnchanged,
     220             :              IndexInfo *indexInfo)
     221             : {
     222     7554712 :     RELATION_CHECKS;
     223     7554712 :     CHECK_REL_PROCEDURE(aminsert);
     224             : 
     225     7554712 :     if (!(indexRelation->rd_indam->ampredlocks))
     226      576860 :         CheckForSerializableConflictIn(indexRelation,
     227             :                                        (ItemPointer) NULL,
     228             :                                        InvalidBlockNumber);
     229             : 
     230     7554712 :     return indexRelation->rd_indam->aminsert(indexRelation, values, isnull,
     231             :                                              heap_t_ctid, heapRelation,
     232             :                                              checkUnique, indexUnchanged,
     233             :                                              indexInfo);
     234             : }
     235             : 
     236             : /* -------------------------
     237             :  *      index_insert_cleanup - clean up after all index inserts are done
     238             :  * -------------------------
     239             :  */
     240             : void
     241     2785672 : index_insert_cleanup(Relation indexRelation,
     242             :                      IndexInfo *indexInfo)
     243             : {
     244     2785672 :     RELATION_CHECKS;
     245             : 
     246     2785672 :     if (indexRelation->rd_indam->aminsertcleanup)
     247        1096 :         indexRelation->rd_indam->aminsertcleanup(indexRelation, indexInfo);
     248     2785672 : }
     249             : 
     250             : /*
     251             :  * index_beginscan - start a scan of an index with amgettuple
     252             :  *
     253             :  * Caller must be holding suitable locks on the heap and the index.
     254             :  */
     255             : IndexScanDesc
     256    10569288 : index_beginscan(Relation heapRelation,
     257             :                 Relation indexRelation,
     258             :                 Snapshot snapshot,
     259             :                 int nkeys, int norderbys)
     260             : {
     261             :     IndexScanDesc scan;
     262             : 
     263             :     Assert(snapshot != InvalidSnapshot);
     264             : 
     265    10569288 :     scan = index_beginscan_internal(indexRelation, nkeys, norderbys, snapshot, NULL, false);
     266             : 
     267             :     /*
     268             :      * Save additional parameters into the scandesc.  Everything else was set
     269             :      * up by RelationGetIndexScan.
     270             :      */
     271    10569288 :     scan->heapRelation = heapRelation;
     272    10569288 :     scan->xs_snapshot = snapshot;
     273             : 
     274             :     /* prepare to fetch index matches from table */
     275    10569288 :     scan->xs_heapfetch = table_index_fetch_begin(heapRelation);
     276             : 
     277    10569288 :     return scan;
     278             : }
     279             : 
     280             : /*
     281             :  * index_beginscan_bitmap - start a scan of an index with amgetbitmap
     282             :  *
     283             :  * As above, caller had better be holding some lock on the parent heap
     284             :  * relation, even though it's not explicitly mentioned here.
     285             :  */
     286             : IndexScanDesc
     287       17094 : index_beginscan_bitmap(Relation indexRelation,
     288             :                        Snapshot snapshot,
     289             :                        int nkeys)
     290             : {
     291             :     IndexScanDesc scan;
     292             : 
     293             :     Assert(snapshot != InvalidSnapshot);
     294             : 
     295       17094 :     scan = index_beginscan_internal(indexRelation, nkeys, 0, snapshot, NULL, false);
     296             : 
     297             :     /*
     298             :      * Save additional parameters into the scandesc.  Everything else was set
     299             :      * up by RelationGetIndexScan.
     300             :      */
     301       17094 :     scan->xs_snapshot = snapshot;
     302             : 
     303       17094 :     return scan;
     304             : }
     305             : 
     306             : /*
     307             :  * index_beginscan_internal --- common code for index_beginscan variants
     308             :  */
     309             : static IndexScanDesc
     310    10586760 : index_beginscan_internal(Relation indexRelation,
     311             :                          int nkeys, int norderbys, Snapshot snapshot,
     312             :                          ParallelIndexScanDesc pscan, bool temp_snap)
     313             : {
     314             :     IndexScanDesc scan;
     315             : 
     316    10586760 :     RELATION_CHECKS;
     317    10586760 :     CHECK_REL_PROCEDURE(ambeginscan);
     318             : 
     319    10586760 :     if (!(indexRelation->rd_indam->ampredlocks))
     320        4624 :         PredicateLockRelation(indexRelation, snapshot);
     321             : 
     322             :     /*
     323             :      * We hold a reference count to the relcache entry throughout the scan.
     324             :      */
     325    10586760 :     RelationIncrementReferenceCount(indexRelation);
     326             : 
     327             :     /*
     328             :      * Tell the AM to open a scan.
     329             :      */
     330    10586760 :     scan = indexRelation->rd_indam->ambeginscan(indexRelation, nkeys,
     331             :                                                 norderbys);
     332             :     /* Initialize information for parallel scan. */
     333    10586760 :     scan->parallel_scan = pscan;
     334    10586760 :     scan->xs_temp_snap = temp_snap;
     335             : 
     336    10586760 :     return scan;
     337             : }
     338             : 
     339             : /* ----------------
     340             :  *      index_rescan  - (re)start a scan of an index
     341             :  *
     342             :  * During a restart, the caller may specify a new set of scankeys and/or
     343             :  * orderbykeys; but the number of keys cannot differ from what index_beginscan
     344             :  * was told.  (Later we might relax that to "must not exceed", but currently
     345             :  * the index AMs tend to assume that scan->numberOfKeys is what to believe.)
     346             :  * To restart the scan without changing keys, pass NULL for the key arrays.
     347             :  * (Of course, keys *must* be passed on the first call, unless
     348             :  * scan->numberOfKeys is zero.)
     349             :  * ----------------
     350             :  */
     351             : void
     352    11023318 : index_rescan(IndexScanDesc scan,
     353             :              ScanKey keys, int nkeys,
     354             :              ScanKey orderbys, int norderbys)
     355             : {
     356             :     SCAN_CHECKS;
     357    11023318 :     CHECK_SCAN_PROCEDURE(amrescan);
     358             : 
     359             :     Assert(nkeys == scan->numberOfKeys);
     360             :     Assert(norderbys == scan->numberOfOrderBys);
     361             : 
     362             :     /* Release resources (like buffer pins) from table accesses */
     363    11023318 :     if (scan->xs_heapfetch)
     364    11002732 :         table_index_fetch_reset(scan->xs_heapfetch);
     365             : 
     366    11023318 :     scan->kill_prior_tuple = false; /* for safety */
     367    11023318 :     scan->xs_heap_continue = false;
     368             : 
     369    11023318 :     scan->indexRelation->rd_indam->amrescan(scan, keys, nkeys,
     370             :                                             orderbys, norderbys);
     371    11023318 : }
     372             : 
     373             : /* ----------------
     374             :  *      index_endscan - end a scan
     375             :  * ----------------
     376             :  */
     377             : void
     378    10585340 : index_endscan(IndexScanDesc scan)
     379             : {
     380             :     SCAN_CHECKS;
     381    10585340 :     CHECK_SCAN_PROCEDURE(amendscan);
     382             : 
     383             :     /* Release resources (like buffer pins) from table accesses */
     384    10585340 :     if (scan->xs_heapfetch)
     385             :     {
     386    10568312 :         table_index_fetch_end(scan->xs_heapfetch);
     387    10568312 :         scan->xs_heapfetch = NULL;
     388             :     }
     389             : 
     390             :     /* End the AM's scan */
     391    10585340 :     scan->indexRelation->rd_indam->amendscan(scan);
     392             : 
     393             :     /* Release index refcount acquired by index_beginscan */
     394    10585340 :     RelationDecrementReferenceCount(scan->indexRelation);
     395             : 
     396    10585340 :     if (scan->xs_temp_snap)
     397         378 :         UnregisterSnapshot(scan->xs_snapshot);
     398             : 
     399             :     /* Release the scan data structure itself */
     400    10585340 :     IndexScanEnd(scan);
     401    10585340 : }
     402             : 
     403             : /* ----------------
     404             :  *      index_markpos  - mark a scan position
     405             :  * ----------------
     406             :  */
     407             : void
     408      130042 : index_markpos(IndexScanDesc scan)
     409             : {
     410             :     SCAN_CHECKS;
     411      130042 :     CHECK_SCAN_PROCEDURE(ammarkpos);
     412             : 
     413      130042 :     scan->indexRelation->rd_indam->ammarkpos(scan);
     414      130042 : }
     415             : 
     416             : /* ----------------
     417             :  *      index_restrpos  - restore a scan position
     418             :  *
     419             :  * NOTE: this only restores the internal scan state of the index AM.  See
     420             :  * comments for ExecRestrPos().
     421             :  *
     422             :  * NOTE: For heap, in the presence of HOT chains, mark/restore only works
     423             :  * correctly if the scan's snapshot is MVCC-safe; that ensures that there's at
     424             :  * most one returnable tuple in each HOT chain, and so restoring the prior
     425             :  * state at the granularity of the index AM is sufficient.  Since the only
     426             :  * current user of mark/restore functionality is nodeMergejoin.c, this
     427             :  * effectively means that merge-join plans only work for MVCC snapshots.  This
     428             :  * could be fixed if necessary, but for now it seems unimportant.
     429             :  * ----------------
     430             :  */
     431             : void
     432       54018 : index_restrpos(IndexScanDesc scan)
     433             : {
     434             :     Assert(IsMVCCSnapshot(scan->xs_snapshot));
     435             : 
     436             :     SCAN_CHECKS;
     437       54018 :     CHECK_SCAN_PROCEDURE(amrestrpos);
     438             : 
     439             :     /* release resources (like buffer pins) from table accesses */
     440       54018 :     if (scan->xs_heapfetch)
     441       54018 :         table_index_fetch_reset(scan->xs_heapfetch);
     442             : 
     443       54018 :     scan->kill_prior_tuple = false; /* for safety */
     444       54018 :     scan->xs_heap_continue = false;
     445             : 
     446       54018 :     scan->indexRelation->rd_indam->amrestrpos(scan);
     447       54018 : }
     448             : 
     449             : /*
     450             :  * index_parallelscan_estimate - estimate shared memory for parallel scan
     451             :  */
     452             : Size
     453          58 : index_parallelscan_estimate(Relation indexRelation, int nkeys, int norderbys,
     454             :                             Snapshot snapshot)
     455             : {
     456             :     Size        nbytes;
     457             : 
     458             :     Assert(snapshot != InvalidSnapshot);
     459             : 
     460          58 :     RELATION_CHECKS;
     461             : 
     462          58 :     nbytes = offsetof(ParallelIndexScanDescData, ps_snapshot_data);
     463          58 :     nbytes = add_size(nbytes, EstimateSnapshotSpace(snapshot));
     464          58 :     nbytes = MAXALIGN(nbytes);
     465             : 
     466             :     /*
     467             :      * If amestimateparallelscan is not provided, assume there is no
     468             :      * AM-specific data needed.  (It's hard to believe that could work, but
     469             :      * it's easy enough to cater to it here.)
     470             :      */
     471          58 :     if (indexRelation->rd_indam->amestimateparallelscan != NULL)
     472          58 :         nbytes = add_size(nbytes,
     473          58 :                           indexRelation->rd_indam->amestimateparallelscan(nkeys,
     474             :                                                                           norderbys));
     475             : 
     476          58 :     return nbytes;
     477             : }
     478             : 
     479             : /*
     480             :  * index_parallelscan_initialize - initialize parallel scan
     481             :  *
     482             :  * We initialize both the ParallelIndexScanDesc proper and the AM-specific
     483             :  * information which follows it.
     484             :  *
     485             :  * This function calls access method specific initialization routine to
     486             :  * initialize am specific information.  Call this just once in the leader
     487             :  * process; then, individual workers attach via index_beginscan_parallel.
     488             :  */
     489             : void
     490          58 : index_parallelscan_initialize(Relation heapRelation, Relation indexRelation,
     491             :                               Snapshot snapshot, ParallelIndexScanDesc target)
     492             : {
     493             :     Size        offset;
     494             : 
     495             :     Assert(snapshot != InvalidSnapshot);
     496             : 
     497          58 :     RELATION_CHECKS;
     498             : 
     499          58 :     offset = add_size(offsetof(ParallelIndexScanDescData, ps_snapshot_data),
     500             :                       EstimateSnapshotSpace(snapshot));
     501          58 :     offset = MAXALIGN(offset);
     502             : 
     503          58 :     target->ps_relid = RelationGetRelid(heapRelation);
     504          58 :     target->ps_indexid = RelationGetRelid(indexRelation);
     505          58 :     target->ps_offset = offset;
     506          58 :     SerializeSnapshot(snapshot, target->ps_snapshot_data);
     507             : 
     508             :     /* aminitparallelscan is optional; assume no-op if not provided by AM */
     509          58 :     if (indexRelation->rd_indam->aminitparallelscan != NULL)
     510             :     {
     511             :         void       *amtarget;
     512             : 
     513          58 :         amtarget = OffsetToPointer(target, offset);
     514          58 :         indexRelation->rd_indam->aminitparallelscan(amtarget);
     515             :     }
     516          58 : }
     517             : 
     518             : /* ----------------
     519             :  *      index_parallelrescan  - (re)start a parallel scan of an index
     520             :  * ----------------
     521             :  */
     522             : void
     523          24 : index_parallelrescan(IndexScanDesc scan)
     524             : {
     525             :     SCAN_CHECKS;
     526             : 
     527          24 :     if (scan->xs_heapfetch)
     528          24 :         table_index_fetch_reset(scan->xs_heapfetch);
     529             : 
     530             :     /* amparallelrescan is optional; assume no-op if not provided by AM */
     531          24 :     if (scan->indexRelation->rd_indam->amparallelrescan != NULL)
     532          24 :         scan->indexRelation->rd_indam->amparallelrescan(scan);
     533          24 : }
     534             : 
     535             : /*
     536             :  * index_beginscan_parallel - join parallel index scan
     537             :  *
     538             :  * Caller must be holding suitable locks on the heap and the index.
     539             :  */
     540             : IndexScanDesc
     541         378 : index_beginscan_parallel(Relation heaprel, Relation indexrel, int nkeys,
     542             :                          int norderbys, ParallelIndexScanDesc pscan)
     543             : {
     544             :     Snapshot    snapshot;
     545             :     IndexScanDesc scan;
     546             : 
     547             :     Assert(RelationGetRelid(heaprel) == pscan->ps_relid);
     548         378 :     snapshot = RestoreSnapshot(pscan->ps_snapshot_data);
     549         378 :     RegisterSnapshot(snapshot);
     550         378 :     scan = index_beginscan_internal(indexrel, nkeys, norderbys, snapshot,
     551             :                                     pscan, true);
     552             : 
     553             :     /*
     554             :      * Save additional parameters into the scandesc.  Everything else was set
     555             :      * up by index_beginscan_internal.
     556             :      */
     557         378 :     scan->heapRelation = heaprel;
     558         378 :     scan->xs_snapshot = snapshot;
     559             : 
     560             :     /* prepare to fetch index matches from table */
     561         378 :     scan->xs_heapfetch = table_index_fetch_begin(heaprel);
     562             : 
     563         378 :     return scan;
     564             : }
     565             : 
     566             : /* ----------------
     567             :  * index_getnext_tid - get the next TID from a scan
     568             :  *
     569             :  * The result is the next TID satisfying the scan keys,
     570             :  * or NULL if no more matching tuples exist.
     571             :  * ----------------
     572             :  */
     573             : ItemPointer
     574    27776736 : index_getnext_tid(IndexScanDesc scan, ScanDirection direction)
     575             : {
     576             :     bool        found;
     577             : 
     578             :     SCAN_CHECKS;
     579    27776736 :     CHECK_SCAN_PROCEDURE(amgettuple);
     580             : 
     581             :     /* XXX: we should assert that a snapshot is pushed or registered */
     582             :     Assert(TransactionIdIsValid(RecentXmin));
     583             : 
     584             :     /*
     585             :      * The AM's amgettuple proc finds the next index entry matching the scan
     586             :      * keys, and puts the TID into scan->xs_heaptid.  It should also set
     587             :      * scan->xs_recheck and possibly scan->xs_itup/scan->xs_hitup, though we
     588             :      * pay no attention to those fields here.
     589             :      */
     590    27776736 :     found = scan->indexRelation->rd_indam->amgettuple(scan, direction);
     591             : 
     592             :     /* Reset kill flag immediately for safety */
     593    27776734 :     scan->kill_prior_tuple = false;
     594    27776734 :     scan->xs_heap_continue = false;
     595             : 
     596             :     /* If we're out of index entries, we're done */
     597    27776734 :     if (!found)
     598             :     {
     599             :         /* release resources (like buffer pins) from table accesses */
     600     5326350 :         if (scan->xs_heapfetch)
     601     5326350 :             table_index_fetch_reset(scan->xs_heapfetch);
     602             : 
     603     5326350 :         return NULL;
     604             :     }
     605             :     Assert(ItemPointerIsValid(&scan->xs_heaptid));
     606             : 
     607    22450384 :     pgstat_count_index_tuples(scan->indexRelation, 1);
     608             : 
     609             :     /* Return the TID of the tuple we found. */
     610    22450384 :     return &scan->xs_heaptid;
     611             : }
     612             : 
     613             : /* ----------------
     614             :  *      index_fetch_heap - get the scan's next heap tuple
     615             :  *
     616             :  * The result is a visible heap tuple associated with the index TID most
     617             :  * recently fetched by index_getnext_tid, or NULL if no more matching tuples
     618             :  * exist.  (There can be more than one matching tuple because of HOT chains,
     619             :  * although when using an MVCC snapshot it should be impossible for more than
     620             :  * one such tuple to exist.)
     621             :  *
     622             :  * On success, the buffer containing the heap tup is pinned (the pin will be
     623             :  * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
     624             :  * call).
     625             :  *
     626             :  * Note: caller must check scan->xs_recheck, and perform rechecking of the
     627             :  * scan keys if required.  We do not do that here because we don't have
     628             :  * enough information to do it efficiently in the general case.
     629             :  * ----------------
     630             :  */
     631             : bool
     632    19357148 : index_fetch_heap(IndexScanDesc scan, TupleTableSlot *slot)
     633             : {
     634    19357148 :     bool        all_dead = false;
     635             :     bool        found;
     636             : 
     637    19357148 :     found = table_index_fetch_tuple(scan->xs_heapfetch, &scan->xs_heaptid,
     638             :                                     scan->xs_snapshot, slot,
     639             :                                     &scan->xs_heap_continue, &all_dead);
     640             : 
     641    19357138 :     if (found)
     642    18326232 :         pgstat_count_heap_fetch(scan->indexRelation);
     643             : 
     644             :     /*
     645             :      * If we scanned a whole HOT chain and found only dead tuples, tell index
     646             :      * AM to kill its entry for that TID (this will take effect in the next
     647             :      * amgettuple call, in index_getnext_tid).  We do not do this when in
     648             :      * recovery because it may violate MVCC to do so.  See comments in
     649             :      * RelationGetIndexScan().
     650             :      */
     651    19357138 :     if (!scan->xactStartedInRecovery)
     652    19032520 :         scan->kill_prior_tuple = all_dead;
     653             : 
     654    19357138 :     return found;
     655             : }
     656             : 
     657             : /* ----------------
     658             :  *      index_getnext_slot - get the next tuple from a scan
     659             :  *
     660             :  * The result is true if a tuple satisfying the scan keys and the snapshot was
     661             :  * found, false otherwise.  The tuple is stored in the specified slot.
     662             :  *
     663             :  * On success, resources (like buffer pins) are likely to be held, and will be
     664             :  * dropped by a future index_getnext_tid, index_fetch_heap or index_endscan
     665             :  * call).
     666             :  *
     667             :  * Note: caller must check scan->xs_recheck, and perform rechecking of the
     668             :  * scan keys if required.  We do not do that here because we don't have
     669             :  * enough information to do it efficiently in the general case.
     670             :  * ----------------
     671             :  */
     672             : bool
     673    22533774 : index_getnext_slot(IndexScanDesc scan, ScanDirection direction, TupleTableSlot *slot)
     674             : {
     675             :     for (;;)
     676             :     {
     677    22533774 :         if (!scan->xs_heap_continue)
     678             :         {
     679             :             ItemPointer tid;
     680             : 
     681             :             /* Time to fetch the next TID from the index */
     682    22390916 :             tid = index_getnext_tid(scan, direction);
     683             : 
     684             :             /* If we're out of index entries, we're done */
     685    22390914 :             if (tid == NULL)
     686     5244234 :                 break;
     687             : 
     688             :             Assert(ItemPointerEquals(tid, &scan->xs_heaptid));
     689             :         }
     690             : 
     691             :         /*
     692             :          * Fetch the next (or only) visible heap tuple for this index entry.
     693             :          * If we don't find anything, loop around and grab the next TID from
     694             :          * the index.
     695             :          */
     696             :         Assert(ItemPointerIsValid(&scan->xs_heaptid));
     697    17289538 :         if (index_fetch_heap(scan, slot))
     698    16465400 :             return true;
     699             :     }
     700             : 
     701     5244234 :     return false;
     702             : }
     703             : 
     704             : /* ----------------
     705             :  *      index_getbitmap - get all tuples at once from an index scan
     706             :  *
     707             :  * Adds the TIDs of all heap tuples satisfying the scan keys to a bitmap.
     708             :  * Since there's no interlock between the index scan and the eventual heap
     709             :  * access, this is only safe to use with MVCC-based snapshots: the heap
     710             :  * item slot could have been replaced by a newer tuple by the time we get
     711             :  * to it.
     712             :  *
     713             :  * Returns the number of matching tuples found.  (Note: this might be only
     714             :  * approximate, so it should only be used for statistical purposes.)
     715             :  * ----------------
     716             :  */
     717             : int64
     718       19650 : index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap)
     719             : {
     720             :     int64       ntids;
     721             : 
     722             :     SCAN_CHECKS;
     723       19650 :     CHECK_SCAN_PROCEDURE(amgetbitmap);
     724             : 
     725             :     /* just make sure this is false... */
     726       19650 :     scan->kill_prior_tuple = false;
     727             : 
     728             :     /*
     729             :      * have the am's getbitmap proc do all the work.
     730             :      */
     731       19650 :     ntids = scan->indexRelation->rd_indam->amgetbitmap(scan, bitmap);
     732             : 
     733       19650 :     pgstat_count_index_tuples(scan->indexRelation, ntids);
     734             : 
     735       19650 :     return ntids;
     736             : }
     737             : 
     738             : /* ----------------
     739             :  *      index_bulk_delete - do mass deletion of index entries
     740             :  *
     741             :  *      callback routine tells whether a given main-heap tuple is
     742             :  *      to be deleted
     743             :  *
     744             :  *      return value is an optional palloc'd struct of statistics
     745             :  * ----------------
     746             :  */
     747             : IndexBulkDeleteResult *
     748        2286 : index_bulk_delete(IndexVacuumInfo *info,
     749             :                   IndexBulkDeleteResult *istat,
     750             :                   IndexBulkDeleteCallback callback,
     751             :                   void *callback_state)
     752             : {
     753        2286 :     Relation    indexRelation = info->index;
     754             : 
     755        2286 :     RELATION_CHECKS;
     756        2286 :     CHECK_REL_PROCEDURE(ambulkdelete);
     757             : 
     758        2286 :     return indexRelation->rd_indam->ambulkdelete(info, istat,
     759             :                                                  callback, callback_state);
     760             : }
     761             : 
     762             : /* ----------------
     763             :  *      index_vacuum_cleanup - do post-deletion cleanup of an index
     764             :  *
     765             :  *      return value is an optional palloc'd struct of statistics
     766             :  * ----------------
     767             :  */
     768             : IndexBulkDeleteResult *
     769       41306 : index_vacuum_cleanup(IndexVacuumInfo *info,
     770             :                      IndexBulkDeleteResult *istat)
     771             : {
     772       41306 :     Relation    indexRelation = info->index;
     773             : 
     774       41306 :     RELATION_CHECKS;
     775       41306 :     CHECK_REL_PROCEDURE(amvacuumcleanup);
     776             : 
     777       41306 :     return indexRelation->rd_indam->amvacuumcleanup(info, istat);
     778             : }
     779             : 
     780             : /* ----------------
     781             :  *      index_can_return
     782             :  *
     783             :  *      Does the index access method support index-only scans for the given
     784             :  *      column?
     785             :  * ----------------
     786             :  */
     787             : bool
     788     1126790 : index_can_return(Relation indexRelation, int attno)
     789             : {
     790     1126790 :     RELATION_CHECKS;
     791             : 
     792             :     /* amcanreturn is optional; assume false if not provided by AM */
     793     1126790 :     if (indexRelation->rd_indam->amcanreturn == NULL)
     794      272808 :         return false;
     795             : 
     796      853982 :     return indexRelation->rd_indam->amcanreturn(indexRelation, attno);
     797             : }
     798             : 
     799             : /* ----------------
     800             :  *      index_getprocid
     801             :  *
     802             :  *      Index access methods typically require support routines that are
     803             :  *      not directly the implementation of any WHERE-clause query operator
     804             :  *      and so cannot be kept in pg_amop.  Instead, such routines are kept
     805             :  *      in pg_amproc.  These registered procedure OIDs are assigned numbers
     806             :  *      according to a convention established by the access method.
     807             :  *      The general index code doesn't know anything about the routines
     808             :  *      involved; it just builds an ordered list of them for
     809             :  *      each attribute on which an index is defined.
     810             :  *
     811             :  *      As of Postgres 8.3, support routines within an operator family
     812             :  *      are further subdivided by the "left type" and "right type" of the
     813             :  *      query operator(s) that they support.  The "default" functions for a
     814             :  *      particular indexed attribute are those with both types equal to
     815             :  *      the index opclass' opcintype (note that this is subtly different
     816             :  *      from the indexed attribute's own type: it may be a binary-compatible
     817             :  *      type instead).  Only the default functions are stored in relcache
     818             :  *      entries --- access methods can use the syscache to look up non-default
     819             :  *      functions.
     820             :  *
     821             :  *      This routine returns the requested default procedure OID for a
     822             :  *      particular indexed attribute.
     823             :  * ----------------
     824             :  */
     825             : RegProcedure
     826     1520568 : index_getprocid(Relation irel,
     827             :                 AttrNumber attnum,
     828             :                 uint16 procnum)
     829             : {
     830             :     RegProcedure *loc;
     831             :     int         nproc;
     832             :     int         procindex;
     833             : 
     834     1520568 :     nproc = irel->rd_indam->amsupport;
     835             : 
     836             :     Assert(procnum > 0 && procnum <= (uint16) nproc);
     837             : 
     838     1520568 :     procindex = (nproc * (attnum - 1)) + (procnum - 1);
     839             : 
     840     1520568 :     loc = irel->rd_support;
     841             : 
     842             :     Assert(loc != NULL);
     843             : 
     844     1520568 :     return loc[procindex];
     845             : }
     846             : 
     847             : /* ----------------
     848             :  *      index_getprocinfo
     849             :  *
     850             :  *      This routine allows index AMs to keep fmgr lookup info for
     851             :  *      support procs in the relcache.  As above, only the "default"
     852             :  *      functions for any particular indexed attribute are cached.
     853             :  *
     854             :  * Note: the return value points into cached data that will be lost during
     855             :  * any relcache rebuild!  Therefore, either use the callinfo right away,
     856             :  * or save it only after having acquired some type of lock on the index rel.
     857             :  * ----------------
     858             :  */
     859             : FmgrInfo *
     860    38934542 : index_getprocinfo(Relation irel,
     861             :                   AttrNumber attnum,
     862             :                   uint16 procnum)
     863             : {
     864             :     FmgrInfo   *locinfo;
     865             :     int         nproc;
     866             :     int         optsproc;
     867             :     int         procindex;
     868             : 
     869    38934542 :     nproc = irel->rd_indam->amsupport;
     870    38934542 :     optsproc = irel->rd_indam->amoptsprocnum;
     871             : 
     872             :     Assert(procnum > 0 && procnum <= (uint16) nproc);
     873             : 
     874    38934542 :     procindex = (nproc * (attnum - 1)) + (procnum - 1);
     875             : 
     876    38934542 :     locinfo = irel->rd_supportinfo;
     877             : 
     878             :     Assert(locinfo != NULL);
     879             : 
     880    38934542 :     locinfo += procindex;
     881             : 
     882             :     /* Initialize the lookup info if first time through */
     883    38934542 :     if (locinfo->fn_oid == InvalidOid)
     884             :     {
     885      920960 :         RegProcedure *loc = irel->rd_support;
     886             :         RegProcedure procId;
     887             : 
     888             :         Assert(loc != NULL);
     889             : 
     890      920960 :         procId = loc[procindex];
     891             : 
     892             :         /*
     893             :          * Complain if function was not found during IndexSupportInitialize.
     894             :          * This should not happen unless the system tables contain bogus
     895             :          * entries for the index opclass.  (If an AM wants to allow a support
     896             :          * function to be optional, it can use index_getprocid.)
     897             :          */
     898      920960 :         if (!RegProcedureIsValid(procId))
     899           0 :             elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
     900             :                  procnum, attnum, RelationGetRelationName(irel));
     901             : 
     902      920960 :         fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
     903             : 
     904      920960 :         if (procnum != optsproc)
     905             :         {
     906             :             /* Initialize locinfo->fn_expr with opclass options Const */
     907      919284 :             bytea     **attoptions = RelationGetIndexAttOptions(irel, false);
     908      919284 :             MemoryContext oldcxt = MemoryContextSwitchTo(irel->rd_indexcxt);
     909             : 
     910      919284 :             set_fn_opclass_options(locinfo, attoptions[attnum - 1]);
     911             : 
     912      919284 :             MemoryContextSwitchTo(oldcxt);
     913             :         }
     914             :     }
     915             : 
     916    38934542 :     return locinfo;
     917             : }
     918             : 
     919             : /* ----------------
     920             :  *      index_store_float8_orderby_distances
     921             :  *
     922             :  *      Convert AM distance function's results (that can be inexact)
     923             :  *      to ORDER BY types and save them into xs_orderbyvals/xs_orderbynulls
     924             :  *      for a possible recheck.
     925             :  * ----------------
     926             :  */
     927             : void
     928      364600 : index_store_float8_orderby_distances(IndexScanDesc scan, Oid *orderByTypes,
     929             :                                      IndexOrderByDistance *distances,
     930             :                                      bool recheckOrderBy)
     931             : {
     932             :     int         i;
     933             : 
     934             :     Assert(distances || !recheckOrderBy);
     935             : 
     936      364600 :     scan->xs_recheckorderby = recheckOrderBy;
     937             : 
     938      729218 :     for (i = 0; i < scan->numberOfOrderBys; i++)
     939             :     {
     940      364618 :         if (orderByTypes[i] == FLOAT8OID)
     941             :         {
     942             : #ifndef USE_FLOAT8_BYVAL
     943             :             /* must free any old value to avoid memory leakage */
     944             :             if (!scan->xs_orderbynulls[i])
     945             :                 pfree(DatumGetPointer(scan->xs_orderbyvals[i]));
     946             : #endif
     947      364488 :             if (distances && !distances[i].isnull)
     948             :             {
     949      364428 :                 scan->xs_orderbyvals[i] = Float8GetDatum(distances[i].value);
     950      364428 :                 scan->xs_orderbynulls[i] = false;
     951             :             }
     952             :             else
     953             :             {
     954          60 :                 scan->xs_orderbyvals[i] = (Datum) 0;
     955          60 :                 scan->xs_orderbynulls[i] = true;
     956             :             }
     957             :         }
     958         130 :         else if (orderByTypes[i] == FLOAT4OID)
     959             :         {
     960             :             /* convert distance function's result to ORDER BY type */
     961          70 :             if (distances && !distances[i].isnull)
     962             :             {
     963          70 :                 scan->xs_orderbyvals[i] = Float4GetDatum((float4) distances[i].value);
     964          70 :                 scan->xs_orderbynulls[i] = false;
     965             :             }
     966             :             else
     967             :             {
     968           0 :                 scan->xs_orderbyvals[i] = (Datum) 0;
     969           0 :                 scan->xs_orderbynulls[i] = true;
     970             :             }
     971             :         }
     972             :         else
     973             :         {
     974             :             /*
     975             :              * If the ordering operator's return value is anything else, we
     976             :              * don't know how to convert the float8 bound calculated by the
     977             :              * distance function to that.  The executor won't actually need
     978             :              * the order by values we return here, if there are no lossy
     979             :              * results, so only insist on converting if the *recheck flag is
     980             :              * set.
     981             :              */
     982          60 :             if (scan->xs_recheckorderby)
     983           0 :                 elog(ERROR, "ORDER BY operator must return float8 or float4 if the distance function is lossy");
     984          60 :             scan->xs_orderbynulls[i] = true;
     985             :         }
     986             :     }
     987      364600 : }
     988             : 
     989             : /* ----------------
     990             :  *      index_opclass_options
     991             :  *
     992             :  *      Parse opclass-specific options for index column.
     993             :  * ----------------
     994             :  */
     995             : bytea *
     996      680314 : index_opclass_options(Relation indrel, AttrNumber attnum, Datum attoptions,
     997             :                       bool validate)
     998             : {
     999      680314 :     int         amoptsprocnum = indrel->rd_indam->amoptsprocnum;
    1000      680314 :     Oid         procid = InvalidOid;
    1001             :     FmgrInfo   *procinfo;
    1002             :     local_relopts relopts;
    1003             : 
    1004             :     /* fetch options support procedure if specified */
    1005      680314 :     if (amoptsprocnum != 0)
    1006      680254 :         procid = index_getprocid(indrel, attnum, amoptsprocnum);
    1007             : 
    1008      680314 :     if (!OidIsValid(procid))
    1009             :     {
    1010             :         Oid         opclass;
    1011             :         Datum       indclassDatum;
    1012             :         oidvector  *indclass;
    1013             : 
    1014      677908 :         if (!DatumGetPointer(attoptions))
    1015      677902 :             return NULL;        /* ok, no options, no procedure */
    1016             : 
    1017             :         /*
    1018             :          * Report an error if the opclass's options-parsing procedure does not
    1019             :          * exist but the opclass options are specified.
    1020             :          */
    1021           6 :         indclassDatum = SysCacheGetAttrNotNull(INDEXRELID, indrel->rd_indextuple,
    1022             :                                                Anum_pg_index_indclass);
    1023           6 :         indclass = (oidvector *) DatumGetPointer(indclassDatum);
    1024           6 :         opclass = indclass->values[attnum - 1];
    1025             : 
    1026           6 :         ereport(ERROR,
    1027             :                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    1028             :                  errmsg("operator class %s has no options",
    1029             :                         generate_opclass_name(opclass))));
    1030             :     }
    1031             : 
    1032        2406 :     init_local_reloptions(&relopts, 0);
    1033             : 
    1034        2406 :     procinfo = index_getprocinfo(indrel, attnum, amoptsprocnum);
    1035             : 
    1036        2406 :     (void) FunctionCall1(procinfo, PointerGetDatum(&relopts));
    1037             : 
    1038        2406 :     return build_local_reloptions(&relopts, attoptions, validate);
    1039             : }

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