From 282d2a03dd30804b01f8042f640d638c2ee76604 Mon Sep 17 00:00:00 2001
From: Tom Lane
Date: Thu, 20 Sep 2007 17:56:33 +0000
Subject: HOT updates.  When we update a tuple without changing any of its
 indexed columns, and the new version can be stored on the same heap page, we
 no longer generate extra index entries for the new version.  Instead, index
 searches follow the HOT-chain links to ensure they find the correct tuple
 version.

In addition, this patch introduces the ability to "prune" dead tuples on a
per-page basis, without having to do a complete VACUUM pass to recover space.
VACUUM is still needed to clean up dead index entries, however.

Pavan Deolasee, with help from a bunch of other people.
---
 src/include/optimizer/var.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'src/include/optimizer')

diff --git a/src/include/optimizer/var.h b/src/include/optimizer/var.h
index 34f8c73f3f6..824ba5a1a4b 100644
--- a/src/include/optimizer/var.h
+++ b/src/include/optimizer/var.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/var.h,v 1.35 2007/01/05 22:19:56 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/var.h,v 1.36 2007/09/20 17:56:32 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,6 +18,7 @@
 
 
 extern Relids pull_varnos(Node *node);
+extern void pull_varattnos(Node *node, Bitmapset **varattnos);
 extern bool contain_var_reference(Node *node, int varno, int varattno,
 					  int levelsup);
 extern bool contain_var_clause(Node *node);
-- 
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