Create infrastructure for 'MinimalTuple' representation of in-memory

tuples with less header overhead than a regular HeapTuple, per my
recent proposal.  Teach TupleTableSlot code how to deal with these.
As proof of concept, change tuplestore.c to store MinimalTuples instead
of HeapTuples.  Future patches will expand the concept to other places
where it is useful.

1 files changed, 4 insertions, 8 deletions

diff --git a/src/backend/tcop/pquery.c b/src/backend/tcop/pquery.c
index 060ce56792..c79d0eae18 100644
--- a/src/backend/tcop/pquery.c
+++ b/src/backend/tcop/pquery.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.101 2006/03/05 15:58:40 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.102 2006/06/27 02:51:39 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -911,21 +911,17 @@ RunFromStore(Portal portal, ScanDirection direction, long count,
 		for (;;)
 		{
 			MemoryContext oldcontext;
-			HeapTuple	tup;
-			bool		should_free;
+			bool		ok;
 
 			oldcontext = MemoryContextSwitchTo(portal->holdContext);
 
-			tup = tuplestore_getheaptuple(portal->holdStore, forward,
-										  &should_free);
+			ok = tuplestore_gettupleslot(portal->holdStore, forward, slot);
 
 			MemoryContextSwitchTo(oldcontext);
 
-			if (tup == NULL)
+			if (!ok)
 				break;
 
-			ExecStoreTuple(tup, slot, InvalidBuffer, should_free);
-
 			(*dest->receiveSlot) (slot, dest);
 
 			ExecClearTuple(slot);