From bf3dbb5881e9b886ee9fe84bca2153c698eea885 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 27 Mar 2005 23:53:05 +0000
Subject: First steps towards index scans with heap access decoupled from index
 access: define new index access method functions 'amgetmulti' that can fetch
 multiple TIDs per call.  (The functions exist but are totally untested as
 yet.)  Since I was modifying pg_am anyway, remove the no-longer-needed 'rel'
 parameter from amcostestimate functions, and also remove the vestigial
 amowner column that was creating useless work for Alvaro's
 shared-object-dependencies project. Initdb forced due to changes in pg_am.

---
 src/backend/access/gist/gistget.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

(limited to 'src/backend/access/gist/gistget.c')

diff --git a/src/backend/access/gist/gistget.c b/src/backend/access/gist/gistget.c
index 03856874f3..8f7a6c7ed4 100644
--- a/src/backend/access/gist/gistget.c
+++ b/src/backend/access/gist/gistget.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/gist/gistget.c,v 1.44 2005/02/05 19:38:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/gist/gistget.c,v 1.45 2005/03/27 23:52:55 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -47,6 +47,33 @@ gistgettuple(PG_FUNCTION_ARGS)
 	PG_RETURN_BOOL(res);
 }
 
+Datum
+gistgetmulti(PG_FUNCTION_ARGS)
+{
+	IndexScanDesc s = (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);
+	bool		res = true;
+	int32		ntids = 0;
+
+	/* XXX generic implementation: loop around guts of gistgettuple */
+	while (ntids < max_tids)
+	{
+		if (ItemPointerIsValid(&(s->currentItemData)))
+			res = gistnext(s, ForwardScanDirection);
+		else
+			res = gistfirst(s, ForwardScanDirection);
+		if (!res)
+			break;
+		tids[ntids] = s->xs_ctup.t_self;
+		ntids++;
+	}
+
+	*returned_tids = ntids;
+	PG_RETURN_BOOL(res);
+}
+
 static bool
 gistfirst(IndexScanDesc s, ScanDirection dir)
 {
-- 
cgit v1.2.1