diff options
Diffstat (limited to 'src/backend/access/nbtree/nbtree.c')
| -rw-r--r-- | src/backend/access/nbtree/nbtree.c | 75 |
1 files changed, 74 insertions, 1 deletions
diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index 1fc26ea8958..82f9051de79 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -12,7 +12,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.126 2005/03/21 01:23:59 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/access/nbtree/nbtree.c,v 1.127 2005/03/27 23:53:00 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -341,6 +341,79 @@ btgettuple(PG_FUNCTION_ARGS) } /* + * btgetmulti() -- get multiple tuples at once + * + * This is a somewhat generic implementation: it avoids the _bt_restscan + * overhead, but there's no smarts about picking especially good stopping + * points such as index page boundaries. + */ +Datum +btgetmulti(PG_FUNCTION_ARGS) +{ + IndexScanDesc scan = (IndexScanDesc) PG_GETARG_POINTER(0); + ItemPointer tids = (ItemPointer) PG_GETARG_POINTER(1); + int32 max_tids = PG_GETARG_INT32(2); + int32 *returned_tids = (int32 *) PG_GETARG_POINTER(3); + BTScanOpaque so = (BTScanOpaque) scan->opaque; + bool res = true; + int32 ntids = 0; + + /* + * Restore prior state if we were already called at least once. + */ + if (ItemPointerIsValid(&(scan->currentItemData))) + _bt_restscan(scan); + + while (ntids < max_tids) + { + /* + * Start scan, or advance to next tuple. + */ + if (ItemPointerIsValid(&(scan->currentItemData))) + res = _bt_next(scan, ForwardScanDirection); + else + res = _bt_first(scan, ForwardScanDirection); + /* + * Skip killed tuples if asked to. + */ + if (scan->ignore_killed_tuples) + { + while (res) + { + Page page; + OffsetNumber offnum; + + offnum = ItemPointerGetOffsetNumber(&(scan->currentItemData)); + page = BufferGetPage(so->btso_curbuf); + if (!ItemIdDeleted(PageGetItemId(page, offnum))) + break; + res = _bt_next(scan, ForwardScanDirection); + } + } + + if (!res) + break; + /* Save tuple ID, and continue scanning */ + tids[ntids] = scan->xs_ctup.t_self; + ntids++; + } + + /* + * Save heap TID to use it in _bt_restscan. Then release the read + * lock on the buffer so that we aren't blocking other backends. + */ + if (res) + { + ((BTScanOpaque) scan->opaque)->curHeapIptr = scan->xs_ctup.t_self; + LockBuffer(((BTScanOpaque) scan->opaque)->btso_curbuf, + BUFFER_LOCK_UNLOCK); + } + + *returned_tids = ntids; + PG_RETURN_BOOL(res); +} + +/* * btbeginscan() -- start a scan on a btree index */ Datum |