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-rw-r--r--src/backend/access/heap/heapam.c130
1 files changed, 52 insertions, 78 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 88926adfe5e..dac14ac3397 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.133 2002/05/01 01:23:37 inoue Exp $
+ * $Header: /cvsroot/pgsql/src/backend/access/heap/heapam.c,v 1.134 2002/05/20 23:51:41 tgl Exp $
*
*
* INTERFACE ROUTINES
@@ -24,7 +24,7 @@
* heap_rescan - restart a relation scan
* heap_endscan - end relation scan
* heap_getnext - retrieve next tuple in scan
- * heap_fetch - retrive tuple with tid
+ * heap_fetch - retrieve tuple with tid
* heap_insert - insert tuple into a relation
* heap_delete - delete a tuple from a relation
* heap_update - replace a tuple in a relation with another tuple
@@ -70,11 +70,7 @@ static XLogRecPtr log_heap_update(Relation reln, Buffer oldbuf,
* ----------------
*/
static void
-initscan(HeapScanDesc scan,
- Relation relation,
- int atend,
- unsigned nkeys,
- ScanKey key)
+initscan(HeapScanDesc scan, ScanKey key)
{
/*
* Make sure we have up-to-date idea of number of blocks in relation.
@@ -82,7 +78,7 @@ initscan(HeapScanDesc scan,
* added while the scan is in progress will be invisible to my
* transaction anyway...
*/
- relation->rd_nblocks = RelationGetNumberOfBlocks(relation);
+ scan->rs_rd->rd_nblocks = RelationGetNumberOfBlocks(scan->rs_rd);
scan->rs_ctup.t_datamcxt = NULL;
scan->rs_ctup.t_data = NULL;
@@ -95,7 +91,7 @@ initscan(HeapScanDesc scan,
* copy the scan key, if appropriate
*/
if (key != NULL)
- memmove(scan->rs_key, key, nkeys * sizeof(ScanKeyData));
+ memcpy(scan->rs_key, key, scan->rs_nkeys * sizeof(ScanKeyData));
}
/* ----------------
@@ -185,7 +181,7 @@ heapgettup(Relation relation,
/*
* calculate next starting lineoff, given scan direction
*/
- if (!dir)
+ if (dir == 0)
{
/*
* ``no movement'' scan direction: refetch same tuple
@@ -216,8 +212,8 @@ heapgettup(Relation relation,
tuple->t_data = (HeapTupleHeader) PageGetItem((Page) dp, lpp);
tuple->t_len = ItemIdGetLength(lpp);
LockBuffer(*buffer, BUFFER_LOCK_UNLOCK);
- return;
+ return;
}
else if (dir < 0)
{
@@ -255,7 +251,6 @@ heapgettup(Relation relation,
OffsetNumberPrev(ItemPointerGetOffsetNumber(tid));
}
/* page and lineoff now reference the physically previous tid */
-
}
else
{
@@ -287,7 +282,6 @@ heapgettup(Relation relation,
dp = (Page) BufferGetPage(*buffer);
lines = PageGetMaxOffsetNumber(dp);
/* page and lineoff now reference the physically next tid */
-
}
/* 'dir' is now non-zero */
@@ -675,11 +669,8 @@ heap_openr(const char *sysRelationName, LOCKMODE lockmode)
* ----------------
*/
HeapScanDesc
-heap_beginscan(Relation relation,
- int atend,
- Snapshot snapshot,
- unsigned nkeys,
- ScanKey key)
+heap_beginscan(Relation relation, Snapshot snapshot,
+ int nkeys, ScanKey key)
{
HeapScanDesc scan;
@@ -715,20 +706,20 @@ heap_beginscan(Relation relation,
scan->rs_rd = relation;
scan->rs_snapshot = snapshot;
- scan->rs_nkeys = (short) nkeys;
-
- pgstat_initstats(&scan->rs_pgstat_info, relation);
+ scan->rs_nkeys = nkeys;
/*
* we do this here instead of in initscan() because heap_rescan also
* calls initscan() and we don't want to allocate memory again
*/
- if (nkeys)
+ if (nkeys > 0)
scan->rs_key = (ScanKey) palloc(sizeof(ScanKeyData) * nkeys);
else
scan->rs_key = NULL;
- initscan(scan, relation, atend, nkeys, key);
+ pgstat_initstats(&scan->rs_pgstat_info, relation);
+
+ initscan(scan, key);
return scan;
}
@@ -739,7 +730,6 @@ heap_beginscan(Relation relation,
*/
void
heap_rescan(HeapScanDesc scan,
- bool scanFromEnd,
ScanKey key)
{
/*
@@ -757,7 +747,7 @@ heap_rescan(HeapScanDesc scan,
/*
* reinitialize scan descriptor
*/
- initscan(scan, scan->rs_rd, scanFromEnd, scan->rs_nkeys, key);
+ initscan(scan, key);
pgstat_reset_heap_scan(&scan->rs_pgstat_info);
}
@@ -808,14 +798,14 @@ heap_endscan(HeapScanDesc scan)
#ifdef HEAPDEBUGALL
#define HEAPDEBUG_1 \
-elog(LOG, "heap_getnext([%s,nkeys=%d],backw=%d) called", \
- RelationGetRelationName(scan->rs_rd), scan->rs_nkeys, backw)
+ elog(LOG, "heap_getnext([%s,nkeys=%d],dir=%d) called", \
+ RelationGetRelationName(scan->rs_rd), scan->rs_nkeys, (int) direction)
#define HEAPDEBUG_2 \
elog(LOG, "heap_getnext returning EOS")
#define HEAPDEBUG_3 \
- elog(LOG, "heap_getnext returning tuple");
+ elog(LOG, "heap_getnext returning tuple")
#else
#define HEAPDEBUG_1
#define HEAPDEBUG_2
@@ -824,7 +814,7 @@ elog(LOG, "heap_getnext([%s,nkeys=%d],backw=%d) called", \
HeapTuple
-heap_getnext(HeapScanDesc scan, int backw)
+heap_getnext(HeapScanDesc scan, ScanDirection direction)
{
/*
* increment access statistics
@@ -842,43 +832,21 @@ heap_getnext(HeapScanDesc scan, int backw)
HEAPDEBUG_1; /* heap_getnext( info ) */
- if (backw)
- {
- /*
- * handle reverse scan
- */
- heapgettup(scan->rs_rd,
- -1,
- &(scan->rs_ctup),
- &(scan->rs_cbuf),
- scan->rs_snapshot,
- scan->rs_nkeys,
- scan->rs_key);
-
- if (scan->rs_ctup.t_data == NULL && !BufferIsValid(scan->rs_cbuf))
- {
- HEAPDEBUG_2; /* heap_getnext returning EOS */
- return NULL;
- }
- }
- else
+ /*
+ * Note: we depend here on the -1/0/1 encoding of ScanDirection.
+ */
+ heapgettup(scan->rs_rd,
+ (int) direction,
+ &(scan->rs_ctup),
+ &(scan->rs_cbuf),
+ scan->rs_snapshot,
+ scan->rs_nkeys,
+ scan->rs_key);
+
+ if (scan->rs_ctup.t_data == NULL && !BufferIsValid(scan->rs_cbuf))
{
- /*
- * handle forward scan
- */
- heapgettup(scan->rs_rd,
- 1,
- &(scan->rs_ctup),
- &(scan->rs_cbuf),
- scan->rs_snapshot,
- scan->rs_nkeys,
- scan->rs_key);
-
- if (scan->rs_ctup.t_data == NULL && !BufferIsValid(scan->rs_cbuf))
- {
- HEAPDEBUG_2; /* heap_getnext returning EOS */
- return NULL;
- }
+ HEAPDEBUG_2; /* heap_getnext returning EOS */
+ return NULL;
}
pgstat_count_heap_scan(&scan->rs_pgstat_info);
@@ -897,16 +865,17 @@ heap_getnext(HeapScanDesc scan, int backw)
}
/* ----------------
- * heap_fetch - retrive tuple with tid
+ * heap_fetch - retrieve tuple with given tid
*
- * Currently ignores LP_IVALID during processing!
+ * On entry, tuple->t_self is the TID to fetch.
*
- * Because this is not part of a scan, there is no way to
- * automatically lock/unlock the shared buffers.
- * For this reason, we require that the user retrieve the buffer
- * value, and they are required to BufferRelease() it when they
- * are done. If they want to make a copy of it before releasing it,
- * they can call heap_copytyple().
+ * If successful (ie, tuple found and passes snapshot time qual),
+ * then the rest of *tuple is filled in, and *userbuf is set to the
+ * buffer holding the tuple. A pin is obtained on the buffer; the
+ * caller must BufferRelease the buffer when done with the tuple.
+ *
+ * If not successful, tuple->t_data is set to NULL and *userbuf is set to
+ * InvalidBuffer.
* ----------------
*/
void
@@ -914,7 +883,7 @@ heap_fetch(Relation relation,
Snapshot snapshot,
HeapTuple tuple,
Buffer *userbuf,
- IndexScanDesc iscan)
+ PgStat_Info *pgstat_info)
{
ItemId lp;
Buffer buffer;
@@ -936,8 +905,9 @@ heap_fetch(Relation relation,
buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid));
if (!BufferIsValid(buffer))
- elog(ERROR, "heap_fetch: %s relation: ReadBuffer(%lx) failed",
- RelationGetRelationName(relation), (long) tid);
+ elog(ERROR, "heap_fetch: %s relation: ReadBuffer(%ld) failed",
+ RelationGetRelationName(relation),
+ (long) ItemPointerGetBlockNumber(tid));
LockBuffer(buffer, BUFFER_LOCK_SHARE);
@@ -990,8 +960,12 @@ heap_fetch(Relation relation,
*/
*userbuf = buffer;
- if (iscan != NULL)
- pgstat_count_heap_fetch(&iscan->xs_pgstat_info);
+ /*
+ * Count the successful fetch in *pgstat_info if given,
+ * otherwise in the relation's default statistics area.
+ */
+ if (pgstat_info != NULL)
+ pgstat_count_heap_fetch(pgstat_info);
else
pgstat_count_heap_fetch(&relation->pgstat_info);
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-08-02 23:36:07 +0000