/*-------------------------------------------------------------------------
*
- * indexam.c--
+ * indexam.c
* general index access method routines
*
- * Copyright (c) 1994, Regents of the University of California
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/access/index/indexam.c,v 1.27 1998/09/07 05:35:30 momjian Exp $
+ * src/backend/access/index/indexam.c
*
* INTERFACE ROUTINES
- * index_open - open an index relation by relationId
- * index_openr - open a index relation by name
- * index_close - close a index relation
- * index_beginscan - start a scan of an index
+ * index_open - open an index relation by relation OID
+ * index_close - close an index relation
+ * index_beginscan - start a scan of an index with amgettuple
+ * index_beginscan_bitmap - start a scan of an index with amgetbitmap
* index_rescan - restart a scan of an index
* index_endscan - end a scan
* index_insert - insert an index tuple into a relation
- * index_delete - delete an item from an index relation
* index_markpos - mark a scan position
* index_restrpos - restore a scan position
- * index_getnext - get the next tuple from a scan
- * ** index_fetch - retrieve tuple with tid
- * ** index_replace - replace a tuple
- * ** index_getattr - get an attribute from an index tuple
- * index_getprocid - get a support procedure id from the rel tuple
- *
- * IndexScanIsValid - check index scan
+ * index_parallelscan_estimate - estimate shared memory for parallel scan
+ * index_parallelscan_initialize - initialize parallel scan
+ * index_parallelrescan - (re)start a parallel scan of an index
+ * index_beginscan_parallel - join parallel index scan
+ * index_getnext_tid - get the next TID from a scan
+ * index_fetch_heap - get the scan's next heap tuple
+ * index_getnext - get the next heap tuple from a scan
+ * index_getbitmap - get all tuples from a scan
+ * index_bulk_delete - bulk deletion of index tuples
+ * index_vacuum_cleanup - post-deletion cleanup of an index
+ * index_can_return - does index support index-only scans?
+ * index_getprocid - get a support procedure OID
+ * index_getprocinfo - get a support procedure's lookup info
*
* NOTES
* This file contains the index_ routines which used
* to be a scattered collection of stuff in access/genam.
*
- * The ** routines: index_fetch, index_replace, and index_getattr
- * have not yet been implemented. They may not be needed.
*
* old comments
* Scans are implemented as follows:
*-------------------------------------------------------------------------
*/
-#include <postgres.h>
+#include "postgres.h"
-#include <access/genam.h>
-#include <utils/relcache.h>
-#include <fmgr.h>
-#include <storage/lmgr.h>
-#include <access/heapam.h>
+#include "access/amapi.h"
+#include "access/relscan.h"
+#include "access/transam.h"
+#include "access/xlog.h"
+#include "catalog/catalog.h"
+#include "catalog/index.h"
+#include "pgstat.h"
+#include "storage/bufmgr.h"
+#include "storage/lmgr.h"
+#include "storage/predicate.h"
+#include "utils/snapmgr.h"
+#include "utils/tqual.h"
-/* ----------------
- * undefine macros we aren't going to use that would otherwise
- * get in our way.. delete is defined in c.h and the am's are
- * defined in heapam.h
- * ----------------
- */
-#undef delete
-#undef aminsert
-#undef amdelete
-#undef ambeginscan
-#undef amrescan
-#undef amendscan
-#undef ammarkpos
-#undef amrestrpos
-#undef amgettuple
/* ----------------------------------------------------------------
* macros used in index_ routines
+ *
+ * Note: the ReindexIsProcessingIndex() check in RELATION_CHECKS is there
+ * to check that we don't try to scan or do retail insertions into an index
+ * that is currently being rebuilt or pending rebuild. This helps to catch
+ * things that don't work when reindexing system catalogs. The assertion
+ * doesn't prevent the actual rebuild because we don't use RELATION_CHECKS
+ * when calling the index AM's ambuild routine, and there is no reason for
+ * ambuild to call its subsidiary routines through this file.
* ----------------------------------------------------------------
*/
#define RELATION_CHECKS \
( \
- AssertMacro(RelationIsValid(relation)), \
- AssertMacro(PointerIsValid(relation->rd_am)) \
+ AssertMacro(RelationIsValid(indexRelation)), \
+ AssertMacro(PointerIsValid(indexRelation->rd_amroutine)), \
+ AssertMacro(!ReindexIsProcessingIndex(RelationGetRelid(indexRelation))) \
)
#define SCAN_CHECKS \
( \
AssertMacro(IndexScanIsValid(scan)), \
- AssertMacro(RelationIsValid(scan->relation)), \
- AssertMacro(PointerIsValid(scan->relation->rd_am)) \
+ AssertMacro(RelationIsValid(scan->indexRelation)), \
+ AssertMacro(PointerIsValid(scan->indexRelation->rd_amroutine)) \
)
-#define GET_REL_PROCEDURE(x,y) \
-( \
- procedure = relation->rd_am->y, \
- (!RegProcedureIsValid(procedure)) ? \
- elog(ERROR, "index_%s: invalid %s regproc", \
- CppAsString(x), CppAsString(y)) \
- : (void)NULL \
-)
+#define CHECK_REL_PROCEDURE(pname) \
+do { \
+ if (indexRelation->rd_amroutine->pname == NULL) \
+ elog(ERROR, "function %s is not defined for index %s", \
+ CppAsString(pname), RelationGetRelationName(indexRelation)); \
+} while(0)
-#define GET_SCAN_PROCEDURE(x,y) \
-( \
- procedure = scan->relation->rd_am->y, \
- (!RegProcedureIsValid(procedure)) ? \
- elog(ERROR, "index_%s: invalid %s regproc", \
- CppAsString(x), CppAsString(y)) \
- : (void)NULL \
-)
+#define CHECK_SCAN_PROCEDURE(pname) \
+do { \
+ if (scan->indexRelation->rd_amroutine->pname == NULL) \
+ elog(ERROR, "function %s is not defined for index %s", \
+ CppAsString(pname), RelationGetRelationName(scan->indexRelation)); \
+} while(0)
+
+static IndexScanDesc index_beginscan_internal(Relation indexRelation,
+ int nkeys, int norderbys, Snapshot snapshot,
+ ParallelIndexScanDesc pscan, bool temp_snap);
/* ----------------------------------------------------------------
* index_ interface functions
* ----------------------------------------------------------------
*/
-/* ----------------
- * index_open - open an index relation by relationId
- *
- * presently the relcache routines do all the work we need
- * to open/close index relations.
- * ----------------
- */
-Relation
-index_open(Oid relationId)
-{
- return RelationIdGetRelation(relationId);
-}
/* ----------------
- * index_openr - open a index relation by name
+ * index_open - open an index relation by relation OID
+ *
+ * If lockmode is not "NoLock", the specified kind of lock is
+ * obtained on the index. (Generally, NoLock should only be
+ * used if the caller knows it has some appropriate lock on the
+ * index already.)
*
- * presently the relcache routines do all the work we need
- * to open/close index relations.
+ * An error is raised if the index does not exist.
+ *
+ * This is a convenience routine adapted for indexscan use.
+ * Some callers may prefer to use relation_open directly.
* ----------------
*/
Relation
-index_openr(char *relationName)
+index_open(Oid relationId, LOCKMODE lockmode)
{
- return RelationNameGetRelation(relationName);
+ Relation r;
+
+ r = relation_open(relationId, lockmode);
+
+ if (r->rd_rel->relkind != RELKIND_INDEX)
+ ereport(ERROR,
+ (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+ errmsg("\"%s\" is not an index",
+ RelationGetRelationName(r))));
+
+ return r;
}
/* ----------------
- * index_close - close a index relation
+ * index_close - close an index relation
+ *
+ * If lockmode is not "NoLock", we then release the specified lock.
*
- * presently the relcache routines do all the work we need
- * to open/close index relations.
+ * Note that it is often sensible to hold a lock beyond index_close;
+ * in that case, the lock is released automatically at xact end.
* ----------------
*/
void
-index_close(Relation relation)
+index_close(Relation relation, LOCKMODE lockmode)
{
+ LockRelId relid = relation->rd_lockInfo.lockRelId;
+
+ Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
+
+ /* The relcache does the real work... */
RelationClose(relation);
+
+ if (lockmode != NoLock)
+ UnlockRelationId(&relid, lockmode);
}
/* ----------------
* index_insert - insert an index tuple into a relation
* ----------------
*/
-InsertIndexResult
-index_insert(Relation relation,
- Datum *datum,
- char *nulls,
+bool
+index_insert(Relation indexRelation,
+ Datum *values,
+ bool *isnull,
ItemPointer heap_t_ctid,
- Relation heapRel)
+ Relation heapRelation,
+ IndexUniqueCheck checkUnique)
{
- RegProcedure procedure;
- InsertIndexResult specificResult;
-
RELATION_CHECKS;
- GET_REL_PROCEDURE(insert, aminsert);
+ CHECK_REL_PROCEDURE(aminsert);
- /* ----------------
- * have the am's insert proc do all the work.
- * ----------------
- */
- specificResult = (InsertIndexResult)
- fmgr(procedure, relation, datum, nulls, heap_t_ctid, heapRel, NULL);
+ if (!(indexRelation->rd_amroutine->ampredlocks))
+ CheckForSerializableConflictIn(indexRelation,
+ (HeapTuple) NULL,
+ InvalidBuffer);
- /* must be pfree'ed */
- return specificResult;
+ return indexRelation->rd_amroutine->aminsert(indexRelation, values, isnull,
+ heap_t_ctid, heapRelation,
+ checkUnique);
}
-/* ----------------
- * index_delete - delete an item from an index relation
- * ----------------
+/*
+ * index_beginscan - start a scan of an index with amgettuple
+ *
+ * Caller must be holding suitable locks on the heap and the index.
*/
-void
-index_delete(Relation relation, ItemPointer indexItem)
+IndexScanDesc
+index_beginscan(Relation heapRelation,
+ Relation indexRelation,
+ Snapshot snapshot,
+ int nkeys, int norderbys)
{
- RegProcedure procedure;
+ IndexScanDesc scan;
- RELATION_CHECKS;
- GET_REL_PROCEDURE(delete, amdelete);
+ scan = index_beginscan_internal(indexRelation, nkeys, norderbys, snapshot, NULL, false);
+
+ /*
+ * Save additional parameters into the scandesc. Everything else was set
+ * up by RelationGetIndexScan.
+ */
+ scan->heapRelation = heapRelation;
+ scan->xs_snapshot = snapshot;
- fmgr(procedure, relation, indexItem);
+ return scan;
}
-/* ----------------
- * index_beginscan - start a scan of an index
- * ----------------
+/*
+ * index_beginscan_bitmap - start a scan of an index with amgetbitmap
+ *
+ * As above, caller had better be holding some lock on the parent heap
+ * relation, even though it's not explicitly mentioned here.
*/
IndexScanDesc
-index_beginscan(Relation relation,
- bool scanFromEnd,
- uint16 numberOfKeys,
- ScanKey key)
+index_beginscan_bitmap(Relation indexRelation,
+ Snapshot snapshot,
+ int nkeys)
+{
+ IndexScanDesc scan;
+
+ scan = index_beginscan_internal(indexRelation, nkeys, 0, snapshot, NULL, false);
+
+ /*
+ * Save additional parameters into the scandesc. Everything else was set
+ * up by RelationGetIndexScan.
+ */
+ scan->xs_snapshot = snapshot;
+
+ return scan;
+}
+
+/*
+ * index_beginscan_internal --- common code for index_beginscan variants
+ */
+static IndexScanDesc
+index_beginscan_internal(Relation indexRelation,
+ int nkeys, int norderbys, Snapshot snapshot,
+ ParallelIndexScanDesc pscan, bool temp_snap)
{
- IndexScanDesc scandesc;
- RegProcedure procedure;
+ IndexScanDesc scan;
RELATION_CHECKS;
- GET_REL_PROCEDURE(beginscan, ambeginscan);
+ CHECK_REL_PROCEDURE(ambeginscan);
+
+ if (!(indexRelation->rd_amroutine->ampredlocks))
+ PredicateLockRelation(indexRelation, snapshot);
- RelationSetRIntentLock(relation);
+ /*
+ * We hold a reference count to the relcache entry throughout the scan.
+ */
+ RelationIncrementReferenceCount(indexRelation);
- scandesc = (IndexScanDesc)
- fmgr(procedure, relation, scanFromEnd, numberOfKeys, key);
+ /*
+ * Tell the AM to open a scan.
+ */
+ scan = indexRelation->rd_amroutine->ambeginscan(indexRelation, nkeys,
+ norderbys);
+ /* Initialize information for parallel scan. */
+ scan->parallel_scan = pscan;
+ scan->xs_temp_snap = temp_snap;
- return scandesc;
+ return scan;
}
/* ----------------
- * index_rescan - restart a scan of an index
+ * index_rescan - (re)start a scan of an index
+ *
+ * During a restart, the caller may specify a new set of scankeys and/or
+ * orderbykeys; but the number of keys cannot differ from what index_beginscan
+ * was told. (Later we might relax that to "must not exceed", but currently
+ * the index AMs tend to assume that scan->numberOfKeys is what to believe.)
+ * To restart the scan without changing keys, pass NULL for the key arrays.
+ * (Of course, keys *must* be passed on the first call, unless
+ * scan->numberOfKeys is zero.)
* ----------------
*/
void
-index_rescan(IndexScanDesc scan, bool scanFromEnd, ScanKey key)
+index_rescan(IndexScanDesc scan,
+ ScanKey keys, int nkeys,
+ ScanKey orderbys, int norderbys)
{
- RegProcedure procedure;
-
SCAN_CHECKS;
- GET_SCAN_PROCEDURE(rescan, amrescan);
+ CHECK_SCAN_PROCEDURE(amrescan);
+
+ Assert(nkeys == scan->numberOfKeys);
+ Assert(norderbys == scan->numberOfOrderBys);
+
+ /* Release any held pin on a heap page */
+ if (BufferIsValid(scan->xs_cbuf))
+ {
+ ReleaseBuffer(scan->xs_cbuf);
+ scan->xs_cbuf = InvalidBuffer;
+ }
- fmgr(procedure, scan, scanFromEnd, key);
+ scan->xs_continue_hot = false;
+
+ scan->kill_prior_tuple = false; /* for safety */
+
+ scan->indexRelation->rd_amroutine->amrescan(scan, keys, nkeys,
+ orderbys, norderbys);
}
/* ----------------
void
index_endscan(IndexScanDesc scan)
{
- RegProcedure procedure;
-
SCAN_CHECKS;
- GET_SCAN_PROCEDURE(endscan, amendscan);
+ CHECK_SCAN_PROCEDURE(amendscan);
+
+ /* Release any held pin on a heap page */
+ if (BufferIsValid(scan->xs_cbuf))
+ {
+ ReleaseBuffer(scan->xs_cbuf);
+ scan->xs_cbuf = InvalidBuffer;
+ }
+
+ /* End the AM's scan */
+ scan->indexRelation->rd_amroutine->amendscan(scan);
- fmgr(procedure, scan);
+ /* Release index refcount acquired by index_beginscan */
+ RelationDecrementReferenceCount(scan->indexRelation);
- RelationUnsetRIntentLock(scan->relation);
+ if (scan->xs_temp_snap)
+ UnregisterSnapshot(scan->xs_snapshot);
+
+ /* Release the scan data structure itself */
+ IndexScanEnd(scan);
}
/* ----------------
void
index_markpos(IndexScanDesc scan)
{
- RegProcedure procedure;
-
SCAN_CHECKS;
- GET_SCAN_PROCEDURE(markpos, ammarkpos);
+ CHECK_SCAN_PROCEDURE(ammarkpos);
- fmgr(procedure, scan);
+ scan->indexRelation->rd_amroutine->ammarkpos(scan);
}
/* ----------------
* index_restrpos - restore a scan position
+ *
+ * NOTE: this only restores the internal scan state of the index AM.
+ * The current result tuple (scan->xs_ctup) doesn't change. See comments
+ * for ExecRestrPos().
+ *
+ * NOTE: in the presence of HOT chains, mark/restore only works correctly
+ * if the scan's snapshot is MVCC-safe; that ensures that there's at most one
+ * returnable tuple in each HOT chain, and so restoring the prior state at the
+ * granularity of the index AM is sufficient. Since the only current user
+ * of mark/restore functionality is nodeMergejoin.c, this effectively means
+ * that merge-join plans only work for MVCC snapshots. This could be fixed
+ * if necessary, but for now it seems unimportant.
* ----------------
*/
void
index_restrpos(IndexScanDesc scan)
{
- RegProcedure procedure;
+ Assert(IsMVCCSnapshot(scan->xs_snapshot));
+
+ SCAN_CHECKS;
+ CHECK_SCAN_PROCEDURE(amrestrpos);
+
+ scan->xs_continue_hot = false;
+
+ scan->kill_prior_tuple = false; /* for safety */
+
+ scan->indexRelation->rd_amroutine->amrestrpos(scan);
+}
+
+/*
+ * index_parallelscan_estimate - estimate shared memory for parallel scan
+ *
+ * Currently, we don't pass any information to the AM-specific estimator,
+ * so it can probably only return a constant. In the future, we might need
+ * to pass more information.
+ */
+Size
+index_parallelscan_estimate(Relation indexRelation, Snapshot snapshot)
+{
+ Size nbytes;
+
+ RELATION_CHECKS;
+
+ nbytes = offsetof(ParallelIndexScanDescData, ps_snapshot_data);
+ nbytes = add_size(nbytes, EstimateSnapshotSpace(snapshot));
+ nbytes = MAXALIGN(nbytes);
+
+ /*
+ * If amestimateparallelscan is not provided, assume there is no
+ * AM-specific data needed. (It's hard to believe that could work, but
+ * it's easy enough to cater to it here.)
+ */
+ if (indexRelation->rd_amroutine->amestimateparallelscan != NULL)
+ nbytes = add_size(nbytes,
+ indexRelation->rd_amroutine->amestimateparallelscan());
+
+ return nbytes;
+}
+
+/*
+ * index_parallelscan_initialize - initialize parallel scan
+ *
+ * We initialize both the ParallelIndexScanDesc proper and the AM-specific
+ * information which follows it.
+ *
+ * This function calls access method specific initialization routine to
+ * initialize am specific information. Call this just once in the leader
+ * process; then, individual workers attach via index_beginscan_parallel.
+ */
+void
+index_parallelscan_initialize(Relation heapRelation, Relation indexRelation,
+ Snapshot snapshot, ParallelIndexScanDesc target)
+{
+ Size offset;
+
+ RELATION_CHECKS;
+
+ offset = add_size(offsetof(ParallelIndexScanDescData, ps_snapshot_data),
+ EstimateSnapshotSpace(snapshot));
+ offset = MAXALIGN(offset);
+
+ target->ps_relid = RelationGetRelid(heapRelation);
+ target->ps_indexid = RelationGetRelid(indexRelation);
+ target->ps_offset = offset;
+ SerializeSnapshot(snapshot, target->ps_snapshot_data);
+
+ /* aminitparallelscan is optional; assume no-op if not provided by AM */
+ if (indexRelation->rd_amroutine->aminitparallelscan != NULL)
+ {
+ void *amtarget;
+
+ amtarget = OffsetToPointer(target, offset);
+ indexRelation->rd_amroutine->aminitparallelscan(amtarget);
+ }
+}
+/* ----------------
+ * index_parallelrescan - (re)start a parallel scan of an index
+ * ----------------
+ */
+void
+index_parallelrescan(IndexScanDesc scan)
+{
SCAN_CHECKS;
- GET_SCAN_PROCEDURE(restrpos, amrestrpos);
- fmgr(procedure, scan);
+ /* amparallelrescan is optional; assume no-op if not provided by AM */
+ if (scan->indexRelation->rd_amroutine->amparallelrescan != NULL)
+ scan->indexRelation->rd_amroutine->amparallelrescan(scan);
+}
+
+/*
+ * index_beginscan_parallel - join parallel index scan
+ *
+ * Caller must be holding suitable locks on the heap and the index.
+ */
+IndexScanDesc
+index_beginscan_parallel(Relation heaprel, Relation indexrel, int nkeys,
+ int norderbys, ParallelIndexScanDesc pscan)
+{
+ Snapshot snapshot;
+ IndexScanDesc scan;
+
+ Assert(RelationGetRelid(heaprel) == pscan->ps_relid);
+ snapshot = RestoreSnapshot(pscan->ps_snapshot_data);
+ RegisterSnapshot(snapshot);
+ scan = index_beginscan_internal(indexrel, nkeys, norderbys, snapshot,
+ pscan, true);
+
+ /*
+ * Save additional parameters into the scandesc. Everything else was set
+ * up by index_beginscan_internal.
+ */
+ scan->heapRelation = heaprel;
+ scan->xs_snapshot = snapshot;
+
+ return scan;
}
/* ----------------
- * index_getnext - get the next tuple from a scan
+ * index_getnext_tid - get the next TID from a scan
*
- * A RetrieveIndexResult is a index tuple/heap tuple pair
+ * The result is the next TID satisfying the scan keys,
+ * or NULL if no more matching tuples exist.
* ----------------
*/
-RetrieveIndexResult
-index_getnext(IndexScanDesc scan,
- ScanDirection direction)
+ItemPointer
+index_getnext_tid(IndexScanDesc scan, ScanDirection direction)
{
- RegProcedure procedure;
- RetrieveIndexResult result;
+ bool found;
SCAN_CHECKS;
- GET_SCAN_PROCEDURE(getnext, amgettuple);
+ CHECK_SCAN_PROCEDURE(amgettuple);
- /* ----------------
- * have the am's gettuple proc do all the work.
- * ----------------
+ Assert(TransactionIdIsValid(RecentGlobalXmin));
+
+ /*
+ * The AM's amgettuple proc finds the next index entry matching the scan
+ * keys, and puts the TID into scan->xs_ctup.t_self. It should also set
+ * scan->xs_recheck and possibly scan->xs_itup, though we pay no attention
+ * to those fields here.
+ */
+ found = scan->indexRelation->rd_amroutine->amgettuple(scan, direction);
+
+ /* Reset kill flag immediately for safety */
+ scan->kill_prior_tuple = false;
+
+ /* If we're out of index entries, we're done */
+ if (!found)
+ {
+ /* ... but first, release any held pin on a heap page */
+ if (BufferIsValid(scan->xs_cbuf))
+ {
+ ReleaseBuffer(scan->xs_cbuf);
+ scan->xs_cbuf = InvalidBuffer;
+ }
+ return NULL;
+ }
+
+ pgstat_count_index_tuples(scan->indexRelation, 1);
+
+ /* Return the TID of the tuple we found. */
+ return &scan->xs_ctup.t_self;
+}
+
+/* ----------------
+ * index_fetch_heap - get the scan's next heap tuple
+ *
+ * The result is a visible heap tuple associated with the index TID most
+ * recently fetched by index_getnext_tid, or NULL if no more matching tuples
+ * exist. (There can be more than one matching tuple because of HOT chains,
+ * although when using an MVCC snapshot it should be impossible for more than
+ * one such tuple to exist.)
+ *
+ * On success, the buffer containing the heap tup is pinned (the pin will be
+ * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
+ * call).
+ *
+ * Note: caller must check scan->xs_recheck, and perform rechecking of the
+ * scan keys if required. We do not do that here because we don't have
+ * enough information to do it efficiently in the general case.
+ * ----------------
+ */
+HeapTuple
+index_fetch_heap(IndexScanDesc scan)
+{
+ ItemPointer tid = &scan->xs_ctup.t_self;
+ bool all_dead = false;
+ bool got_heap_tuple;
+
+ /* We can skip the buffer-switching logic if we're in mid-HOT chain. */
+ if (!scan->xs_continue_hot)
+ {
+ /* Switch to correct buffer if we don't have it already */
+ Buffer prev_buf = scan->xs_cbuf;
+
+ scan->xs_cbuf = ReleaseAndReadBuffer(scan->xs_cbuf,
+ scan->heapRelation,
+ ItemPointerGetBlockNumber(tid));
+
+ /*
+ * Prune page, but only if we weren't already on this page
+ */
+ if (prev_buf != scan->xs_cbuf)
+ heap_page_prune_opt(scan->heapRelation, scan->xs_cbuf);
+ }
+
+ /* Obtain share-lock on the buffer so we can examine visibility */
+ LockBuffer(scan->xs_cbuf, BUFFER_LOCK_SHARE);
+ got_heap_tuple = heap_hot_search_buffer(tid, scan->heapRelation,
+ scan->xs_cbuf,
+ scan->xs_snapshot,
+ &scan->xs_ctup,
+ &all_dead,
+ !scan->xs_continue_hot);
+ LockBuffer(scan->xs_cbuf, BUFFER_LOCK_UNLOCK);
+
+ if (got_heap_tuple)
+ {
+ /*
+ * Only in a non-MVCC snapshot can more than one member of the HOT
+ * chain be visible.
+ */
+ scan->xs_continue_hot = !IsMVCCSnapshot(scan->xs_snapshot);
+ pgstat_count_heap_fetch(scan->indexRelation);
+ return &scan->xs_ctup;
+ }
+
+ /* We've reached the end of the HOT chain. */
+ scan->xs_continue_hot = false;
+
+ /*
+ * If we scanned a whole HOT chain and found only dead tuples, tell index
+ * AM to kill its entry for that TID (this will take effect in the next
+ * amgettuple call, in index_getnext_tid). We do not do this when in
+ * recovery because it may violate MVCC to do so. See comments in
+ * RelationGetIndexScan().
*/
- result = (RetrieveIndexResult) fmgr(procedure, scan, direction);
+ if (!scan->xactStartedInRecovery)
+ scan->kill_prior_tuple = all_dead;
+
+ return NULL;
+}
+
+/* ----------------
+ * index_getnext - get the next heap tuple from a scan
+ *
+ * The result is the next heap tuple satisfying the scan keys and the
+ * snapshot, or NULL if no more matching tuples exist.
+ *
+ * On success, the buffer containing the heap tup is pinned (the pin will be
+ * dropped in a future index_getnext_tid, index_fetch_heap or index_endscan
+ * call).
+ *
+ * Note: caller must check scan->xs_recheck, and perform rechecking of the
+ * scan keys if required. We do not do that here because we don't have
+ * enough information to do it efficiently in the general case.
+ * ----------------
+ */
+HeapTuple
+index_getnext(IndexScanDesc scan, ScanDirection direction)
+{
+ HeapTuple heapTuple;
+ ItemPointer tid;
+
+ for (;;)
+ {
+ if (scan->xs_continue_hot)
+ {
+ /*
+ * We are resuming scan of a HOT chain after having returned an
+ * earlier member. Must still hold pin on current heap page.
+ */
+ Assert(BufferIsValid(scan->xs_cbuf));
+ Assert(ItemPointerGetBlockNumber(&scan->xs_ctup.t_self) ==
+ BufferGetBlockNumber(scan->xs_cbuf));
+ }
+ else
+ {
+ /* Time to fetch the next TID from the index */
+ tid = index_getnext_tid(scan, direction);
- return result;
+ /* If we're out of index entries, we're done */
+ if (tid == NULL)
+ break;
+ }
+
+ /*
+ * Fetch the next (or only) visible heap tuple for this index entry.
+ * If we don't find anything, loop around and grab the next TID from
+ * the index.
+ */
+ heapTuple = index_fetch_heap(scan);
+ if (heapTuple != NULL)
+ return heapTuple;
+ }
+
+ return NULL; /* failure exit */
+}
+
+/* ----------------
+ * index_getbitmap - get all tuples at once from an index scan
+ *
+ * Adds the TIDs of all heap tuples satisfying the scan keys to a bitmap.
+ * Since there's no interlock between the index scan and the eventual heap
+ * access, this is only safe to use with MVCC-based snapshots: the heap
+ * item slot could have been replaced by a newer tuple by the time we get
+ * to it.
+ *
+ * Returns the number of matching tuples found. (Note: this might be only
+ * approximate, so it should only be used for statistical purposes.)
+ * ----------------
+ */
+int64
+index_getbitmap(IndexScanDesc scan, TIDBitmap *bitmap)
+{
+ int64 ntids;
+
+ SCAN_CHECKS;
+ CHECK_SCAN_PROCEDURE(amgetbitmap);
+
+ /* just make sure this is false... */
+ scan->kill_prior_tuple = false;
+
+ /*
+ * have the am's getbitmap proc do all the work.
+ */
+ ntids = scan->indexRelation->rd_amroutine->amgetbitmap(scan, bitmap);
+
+ pgstat_count_index_tuples(scan->indexRelation, ntids);
+
+ return ntids;
+}
+
+/* ----------------
+ * index_bulk_delete - do mass deletion of index entries
+ *
+ * callback routine tells whether a given main-heap tuple is
+ * to be deleted
+ *
+ * return value is an optional palloc'd struct of statistics
+ * ----------------
+ */
+IndexBulkDeleteResult *
+index_bulk_delete(IndexVacuumInfo *info,
+ IndexBulkDeleteResult *stats,
+ IndexBulkDeleteCallback callback,
+ void *callback_state)
+{
+ Relation indexRelation = info->index;
+
+ RELATION_CHECKS;
+ CHECK_REL_PROCEDURE(ambulkdelete);
+
+ return indexRelation->rd_amroutine->ambulkdelete(info, stats,
+ callback, callback_state);
+}
+
+/* ----------------
+ * index_vacuum_cleanup - do post-deletion cleanup of an index
+ *
+ * return value is an optional palloc'd struct of statistics
+ * ----------------
+ */
+IndexBulkDeleteResult *
+index_vacuum_cleanup(IndexVacuumInfo *info,
+ IndexBulkDeleteResult *stats)
+{
+ Relation indexRelation = info->index;
+
+ RELATION_CHECKS;
+ CHECK_REL_PROCEDURE(amvacuumcleanup);
+
+ return indexRelation->rd_amroutine->amvacuumcleanup(info, stats);
+}
+
+/* ----------------
+ * index_can_return
+ *
+ * Does the index access method support index-only scans for the given
+ * column?
+ * ----------------
+ */
+bool
+index_can_return(Relation indexRelation, int attno)
+{
+ RELATION_CHECKS;
+
+ /* amcanreturn is optional; assume FALSE if not provided by AM */
+ if (indexRelation->rd_amroutine->amcanreturn == NULL)
+ return false;
+
+ return indexRelation->rd_amroutine->amcanreturn(indexRelation, attno);
}
/* ----------------
* index_getprocid
*
- * Some indexed access methods may require support routines that are
- * not in the operator class/operator model imposed by pg_am. These
- * access methods may store the OIDs of registered procedures they
- * need in pg_amproc. These registered procedure OIDs are ordered in
- * a way that makes sense to the access method, and used only by the
- * access method. The general index code doesn't know anything about
- * the routines involved; it just builds an ordered list of them for
+ * Index access methods typically require support routines that are
+ * not directly the implementation of any WHERE-clause query operator
+ * and so cannot be kept in pg_amop. Instead, such routines are kept
+ * in pg_amproc. These registered procedure OIDs are assigned numbers
+ * according to a convention established by the access method.
+ * The general index code doesn't know anything about the routines
+ * involved; it just builds an ordered list of them for
* each attribute on which an index is defined.
*
- * This routine returns the requested procedure OID for a particular
- * indexed attribute.
+ * As of Postgres 8.3, support routines within an operator family
+ * are further subdivided by the "left type" and "right type" of the
+ * query operator(s) that they support. The "default" functions for a
+ * particular indexed attribute are those with both types equal to
+ * the index opclass' opcintype (note that this is subtly different
+ * from the indexed attribute's own type: it may be a binary-compatible
+ * type instead). Only the default functions are stored in relcache
+ * entries --- access methods can use the syscache to look up non-default
+ * functions.
+ *
+ * This routine returns the requested default procedure OID for a
+ * particular indexed attribute.
* ----------------
*/
RegProcedure
uint16 procnum)
{
RegProcedure *loc;
- int natts;
+ int nproc;
+ int procindex;
+
+ nproc = irel->rd_amroutine->amsupport;
+
+ Assert(procnum > 0 && procnum <= (uint16) nproc);
- natts = irel->rd_rel->relnatts;
+ procindex = (nproc * (attnum - 1)) + (procnum - 1);
loc = irel->rd_support;
Assert(loc != NULL);
- return loc[(natts * (procnum - 1)) + (attnum - 1)];
+ return loc[procindex];
}
-Datum
-GetIndexValue(HeapTuple tuple,
- TupleDesc hTupDesc,
- int attOff,
- AttrNumber *attrNums,
- FuncIndexInfo *fInfo,
- bool *attNull)
+/* ----------------
+ * index_getprocinfo
+ *
+ * This routine allows index AMs to keep fmgr lookup info for
+ * support procs in the relcache. As above, only the "default"
+ * functions for any particular indexed attribute are cached.
+ *
+ * Note: the return value points into cached data that will be lost during
+ * any relcache rebuild! Therefore, either use the callinfo right away,
+ * or save it only after having acquired some type of lock on the index rel.
+ * ----------------
+ */
+FmgrInfo *
+index_getprocinfo(Relation irel,
+ AttrNumber attnum,
+ uint16 procnum)
{
- Datum returnVal;
- bool isNull;
+ FmgrInfo *locinfo;
+ int nproc;
+ int procindex;
+
+ nproc = irel->rd_amroutine->amsupport;
+
+ Assert(procnum > 0 && procnum <= (uint16) nproc);
+
+ procindex = (nproc * (attnum - 1)) + (procnum - 1);
+
+ locinfo = irel->rd_supportinfo;
+
+ Assert(locinfo != NULL);
- if (PointerIsValid(fInfo) && FIgetProcOid(fInfo) != InvalidOid)
+ locinfo += procindex;
+
+ /* Initialize the lookup info if first time through */
+ if (locinfo->fn_oid == InvalidOid)
{
- int i;
- Datum *attData = (Datum *) palloc(FIgetnArgs(fInfo) * sizeof(Datum));
+ RegProcedure *loc = irel->rd_support;
+ RegProcedure procId;
- for (i = 0; i < FIgetnArgs(fInfo); i++)
- {
- attData[i] = heap_getattr(tuple,
- attrNums[i],
- hTupDesc,
- attNull);
- }
- returnVal = (Datum) fmgr_array_args(FIgetProcOid(fInfo),
- FIgetnArgs(fInfo),
- (char **) attData,
- &isNull);
- pfree(attData);
- *attNull = FALSE;
+ Assert(loc != NULL);
+
+ procId = loc[procindex];
+
+ /*
+ * Complain if function was not found during IndexSupportInitialize.
+ * This should not happen unless the system tables contain bogus
+ * entries for the index opclass. (If an AM wants to allow a support
+ * function to be optional, it can use index_getprocid.)
+ */
+ if (!RegProcedureIsValid(procId))
+ elog(ERROR, "missing support function %d for attribute %d of index \"%s\"",
+ procnum, attnum, RelationGetRelationName(irel));
+
+ fmgr_info_cxt(procId, locinfo, irel->rd_indexcxt);
}
- else
- returnVal = heap_getattr(tuple, attrNums[attOff], hTupDesc, attNull);
- return returnVal;
+ return locinfo;
}
projects / postgresql / blobdiff