diff options
Diffstat (limited to 'src/backend/access/heap/heapam.c')
| -rw-r--r-- | src/backend/access/heap/heapam.c | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index 695ef36b509..bff84588fc2 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.164 2004/04/01 21:28:43 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.165 2004/04/21 18:24:23 tgl Exp $ * * * INTERFACE ROUTINES @@ -889,6 +889,28 @@ heap_fetch(Relation relation, bool keep_buf, PgStat_Info *pgstat_info) { + /* Assume *userbuf is undefined on entry */ + *userbuf = InvalidBuffer; + return heap_release_fetch(relation, snapshot, tuple, + userbuf, keep_buf, pgstat_info); +} + +/* + * heap_release_fetch - retrieve tuple with given tid + * + * This has the same API as heap_fetch except that if *userbuf is not + * InvalidBuffer on entry, that buffer will be released before reading + * the new page. This saves a separate ReleaseBuffer step and hence + * one entry into the bufmgr when looping through multiple fetches. + */ +bool +heap_release_fetch(Relation relation, + Snapshot snapshot, + HeapTuple tuple, + Buffer *userbuf, + bool keep_buf, + PgStat_Info *pgstat_info) +{ ItemPointer tid = &(tuple->t_self); ItemId lp; Buffer buffer; @@ -898,9 +920,10 @@ heap_fetch(Relation relation, /* * get the buffer from the relation descriptor. Note that this does a - * buffer pin. + * buffer pin, and releases the old *userbuf if not InvalidBuffer. */ - buffer = ReadBuffer(relation, ItemPointerGetBlockNumber(tid)); + buffer = ReleaseAndReadBuffer(*userbuf, relation, + ItemPointerGetBlockNumber(tid)); if (!BufferIsValid(buffer)) elog(ERROR, "ReadBuffer(\"%s\", %lu) failed", |