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synced 2025-06-11 20:28:21 +03:00
Restructure indexscan API (index_beginscan, index_getnext) per
yesterday's proposal to pghackers. Also remove unnecessary parameters to heap_beginscan, heap_rescan. I modified pg_proc.h to reflect the new numbers of parameters for the AM interface routines, but did not force an initdb because nothing actually looks at those fields.
This commit is contained in:
Tom Lane
@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.133 2002/05/01 01:23:37 inoue Exp $
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* $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.134 2002/05/20 23:51:41 tgl Exp $
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*
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*
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* INTERFACE ROUTINES
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@ -24,7 +24,7 @@
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* heap_rescan - restart a relation scan
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* heap_endscan - end relation scan
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* heap_getnext - retrieve next tuple in scan
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* heap_fetch - retrive tuple with tid
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* heap_fetch - retrieve tuple with tid
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* heap_insert - insert tuple into a relation
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* heap_delete - delete a tuple from a relation
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* heap_update - replace a tuple in a relation with another tuple
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@ -70,11 +70,7 @@ static XLogRecPtr log_heap_update(Relation reln, Buffer oldbuf,
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* ----------------
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*/
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static void
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initscan(HeapScanDesc scan,
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Relation relation,
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int atend,
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unsigned nkeys,
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ScanKey key)
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initscan(HeapScanDesc scan, ScanKey key)
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{
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/*
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* Make sure we have up-to-date idea of number of blocks in relation.
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@ -82,7 +78,7 @@ initscan(HeapScanDesc scan,
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* added while the scan is in progress will be invisible to my
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* transaction anyway...
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*/
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relation->rd_nblocks = RelationGetNumberOfBlocks(relation);
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scan->rs_rd->rd_nblocks = RelationGetNumberOfBlocks(scan->rs_rd);
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scan->rs_ctup.t_datamcxt = NULL;
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scan->rs_ctup.t_data = NULL;
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@ -95,7 +91,7 @@ initscan(HeapScanDesc scan,
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* copy the scan key, if appropriate
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*/
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if (key != NULL)
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memmove(scan->rs_key, key, nkeys * sizeof(ScanKeyData));
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memcpy(scan->rs_key, key, scan->rs_nkeys * sizeof(ScanKeyData));
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}
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/* ----------------
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@ -185,7 +181,7 @@ heapgettup(Relation relation,
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/*
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* calculate next starting lineoff, given scan direction
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*/
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if (!dir)
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if (dir == 0)
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{
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/*
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* ``no movement'' scan direction: refetch same tuple
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@ -216,8 +212,8 @@ heapgettup(Relation relation,
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tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lpp);
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tuple->t_len = ItemIdGetLength(lpp);
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LockBuffer(*buffer, BUFFER_LOCK_UNLOCK);
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return;
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return;
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}
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else if (dir < 0)
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{
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@ -255,7 +251,6 @@ heapgettup(Relation relation,
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OffsetNumberPrev(ItemPointerGetOffsetNumber(tid));
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}
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/* page and lineoff now reference the physically previous tid */
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}
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else
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{
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@ -287,7 +282,6 @@ heapgettup(Relation relation,
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dp = (Page) BufferGetPage(*buffer);
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lines = PageGetMaxOffsetNumber(dp);
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/* page and lineoff now reference the physically next tid */
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}
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/* 'dir' is now non-zero */
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@ -675,11 +669,8 @@ heap_openr(const char *sysRelationName, LOCKMODE lockmode)
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* ----------------
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*/
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HeapScanDesc
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heap_beginscan(Relation relation,
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int atend,
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Snapshot snapshot,
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unsigned nkeys,
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ScanKey key)
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heap_beginscan(Relation relation, Snapshot snapshot,
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int nkeys, ScanKey key)
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{
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HeapScanDesc scan;
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@ -715,20 +706,20 @@ heap_beginscan(Relation relation,
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scan->rs_rd = relation;
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scan->rs_snapshot = snapshot;
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scan->rs_nkeys = (short) nkeys;
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pgstat_initstats(&scan->rs_pgstat_info, relation);
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scan->rs_nkeys = nkeys;
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/*
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* we do this here instead of in initscan() because heap_rescan also
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* calls initscan() and we don't want to allocate memory again
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*/
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if (nkeys)
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if (nkeys > 0)
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scan->rs_key = (ScanKey) palloc(sizeof(ScanKeyData) * nkeys);
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else
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scan->rs_key = NULL;
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initscan(scan, relation, atend, nkeys, key);
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pgstat_initstats(&scan->rs_pgstat_info, relation);
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initscan(scan, key);
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return scan;
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}
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@ -739,7 +730,6 @@ heap_beginscan(Relation relation,
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*/
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void
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heap_rescan(HeapScanDesc scan,
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bool scanFromEnd,
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ScanKey key)
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{
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/*
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@ -757,7 +747,7 @@ heap_rescan(HeapScanDesc scan,
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/*
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* reinitialize scan descriptor
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*/
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initscan(scan, scan->rs_rd, scanFromEnd, scan->rs_nkeys, key);
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initscan(scan, key);
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pgstat_reset_heap_scan(&scan->rs_pgstat_info);
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}
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@ -808,14 +798,14 @@ heap_endscan(HeapScanDesc scan)
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#ifdef HEAPDEBUGALL
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#define HEAPDEBUG_1 \
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elog(LOG, "heap_getnext([%s,nkeys=%d],backw=%d) called", \
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RelationGetRelationName(scan->rs_rd), scan->rs_nkeys, backw)
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elog(LOG, "heap_getnext([%s,nkeys=%d],dir=%d) called", \
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RelationGetRelationName(scan->rs_rd), scan->rs_nkeys, (int) direction)
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#define HEAPDEBUG_2 \
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elog(LOG, "heap_getnext returning EOS")
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#define HEAPDEBUG_3 \
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elog(LOG, "heap_getnext returning tuple");
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elog(LOG, "heap_getnext returning tuple")
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#else
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#define HEAPDEBUG_1
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#define HEAPDEBUG_2
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@ -824,7 +814,7 @@ elog(LOG, "heap_getnext([%s,nkeys=%d],backw=%d) called", \
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HeapTuple
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heap_getnext(HeapScanDesc scan, int backw)
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heap_getnext(HeapScanDesc scan, ScanDirection direction)
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{
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/*
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* increment access statistics
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@ -842,43 +832,21 @@ heap_getnext(HeapScanDesc scan, int backw)
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HEAPDEBUG_1; /* heap_getnext( info ) */
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if (backw)
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{
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/*
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* handle reverse scan
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*/
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heapgettup(scan->rs_rd,
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-1,
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&(scan->rs_ctup),
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&(scan->rs_cbuf),
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scan->rs_snapshot,
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scan->rs_nkeys,
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scan->rs_key);
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/*
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* Note: we depend here on the -1/0/1 encoding of ScanDirection.
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*/
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heapgettup(scan->rs_rd,
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(int) direction,
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&(scan->rs_ctup),
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&(scan->rs_cbuf),
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scan->rs_snapshot,
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scan->rs_nkeys,
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scan->rs_key);
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if (scan->rs_ctup.t_data == NULL && !BufferIsValid(scan->rs_cbuf))
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{
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HEAPDEBUG_2; /* heap_getnext returning EOS */
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return NULL;
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}
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}
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else
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if (scan->rs_ctup.t_data == NULL && !BufferIsValid(scan->rs_cbuf))
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{
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/*
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* handle forward scan
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*/
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heapgettup(scan->rs_rd,
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1,
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&(scan->rs_ctup),
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&(scan->rs_cbuf),
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scan->rs_snapshot,
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scan->rs_nkeys,
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scan->rs_key);
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if (scan->rs_ctup.t_data == NULL && !BufferIsValid(scan->rs_cbuf))
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{
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HEAPDEBUG_2; /* heap_getnext returning EOS */
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return NULL;
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}
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HEAPDEBUG_2; /* heap_getnext returning EOS */
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return NULL;
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}
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pgstat_count_heap_scan(&scan->rs_pgstat_info);
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@ -897,16 +865,17 @@ heap_getnext(HeapScanDesc scan, int backw)
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}
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/* ----------------
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* heap_fetch - retrive tuple with tid
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* heap_fetch - retrieve tuple with given tid
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*
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* Currently ignores LP_IVALID during processing!
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* On entry, tuple->t_self is the TID to fetch.
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*
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* Because this is not part of a scan, there is no way to
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* automatically lock/unlock the shared buffers.
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* For this reason, we require that the user retrieve the buffer
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* value, and they are required to BufferRelease() it when they
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* are done. If they want to make a copy of it before releasing it,
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* they can call heap_copytyple().
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* If successful (ie, tuple found and passes snapshot time qual),
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* then the rest of *tuple is filled in, and *userbuf is set to the
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* buffer holding the tuple. A pin is obtained on the buffer; the
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* caller must BufferRelease the buffer when done with the tuple.
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*
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* If not successful, tuple->t_data is set to NULL and *userbuf is set to
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* InvalidBuffer.
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* ----------------
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*/
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void
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@ -914,7 +883,7 @@ heap_fetch(Relation relation,
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Snapshot snapshot,
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HeapTuple tuple,
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Buffer *userbuf,
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IndexScanDesc iscan)
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PgStat_Info *pgstat_info)
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{
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ItemId lp;
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Buffer buffer;
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@ -936,8 +905,9 @@ heap_fetch(Relation relation,
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buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
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if (!BufferIsValid(buffer))
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elog(ERROR, "heap_fetch: %s relation: ReadBuffer(%lx) failed",
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RelationGetRelationName(relation), (long) tid);
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elog(ERROR, "heap_fetch: %s relation: ReadBuffer(%ld) failed",
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RelationGetRelationName(relation),
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(long) ItemPointerGetBlockNumber(tid));
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LockBuffer(buffer, BUFFER_LOCK_SHARE);
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@ -990,8 +960,12 @@ heap_fetch(Relation relation,
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*/
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*userbuf = buffer;
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if (iscan != NULL)
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pgstat_count_heap_fetch(&iscan->xs_pgstat_info);
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/*
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* Count the successful fetch in *pgstat_info if given,
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* otherwise in the relation's default statistics area.
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*/
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if (pgstat_info != NULL)
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pgstat_count_heap_fetch(pgstat_info);
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else
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pgstat_count_heap_fetch(&relation->pgstat_info);
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}
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