Create new routines systable_beginscan_ordered, systable_getnext_ordered,

systable_endscan_ordered that have API similar to systable_beginscan etc
(in particular, the passed-in scankeys have heap not index attnums),
but guarantee ordered output, unlike the existing functions.  For the moment
these are just very thin wrappers around index_beginscan/index_getnext/etc.
Someday they might need to get smarter; but for now this is just a code
refactoring exercise to reduce the number of direct callers of index_getnext,
in preparation for changing that function's API.

In passing, remove index_getnext_indexitem, which has been dead code for
quite some time, and will have even less use than that in the presence
of run-time-lossy indexes.

1 files changed, 2 insertions, 46 deletions

diff --git a/src/backend/access/index/indexam.c b/src/backend/access/index/indexam.c
index d59f1529db..7a06d0074e 100644
--- a/src/backend/access/index/indexam.c
+++ b/src/backend/access/index/indexam.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.105 2008/04/10 22:25:25 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/index/indexam.c,v 1.106 2008/04/12 23:14:21 tgl Exp $
  *
  * INTERFACE ROUTINES
  *		index_open		- open an index relation by relation OID
@@ -206,12 +206,7 @@ index_insert(Relation indexRelation,
 /*
  * index_beginscan - start a scan of an index with amgettuple
  *
- * Note: heapRelation may be NULL if there is no intention of calling
- * index_getnext on this scan; index_getnext_indexitem will not use the
- * heapRelation link (nor the snapshot).  However, the caller had better
- * be holding some kind of lock on the heap relation in any case, to ensure
- * no one deletes it (or the index) out from under us.	Caller must also
- * be holding a lock on the index.
+ * Caller must be holding suitable locks on the heap and the index.
  */
 IndexScanDesc
 index_beginscan(Relation heapRelation,
@@ -635,45 +630,6 @@ index_getnext(IndexScanDesc scan, ScanDirection direction)
 }
 
 /* ----------------
- *		index_getnext_indexitem - get the next index tuple from a scan
- *
- * Finds the next index tuple satisfying the scan keys.  Note that the
- * corresponding heap tuple is not accessed, and thus no time qual (snapshot)
- * check is done, other than the index AM's internal check for killed tuples
- * (which most callers of this routine will probably want to suppress by
- * setting scan->ignore_killed_tuples = false).
- *
- * On success (TRUE return), the heap TID of the found index entry is in
- * scan->xs_ctup.t_self.  scan->xs_cbuf is untouched.
- * ----------------
- */
-bool
-index_getnext_indexitem(IndexScanDesc scan,
-						ScanDirection direction)
-{
-	FmgrInfo   *procedure;
-	bool		found;
-
-	SCAN_CHECKS;
-	GET_SCAN_PROCEDURE(amgettuple);
-
-	/* just make sure this is false... */
-	scan->kill_prior_tuple = false;
-
-	/*
-	 * have the am's gettuple proc do all the work.
-	 */
-	found = DatumGetBool(FunctionCall2(procedure,
-									   PointerGetDatum(scan),
-									   Int32GetDatum(direction)));
-
-	if (found)
-		pgstat_count_index_tuples(scan->indexRelation, 1);
-
-	return found;
-}
-
-/* ----------------
  *		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.