From 81f2d972a82fd86b5a01b2ddea7b8e866a760f5e Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 29 Jul 2005 21:40:26 +0000
Subject: [PATCH] Back-patch fix for NOT-below-a-NOT case.

---
 src/backend/optimizer/prep/prepqual.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/backend/optimizer/prep/prepqual.c b/src/backend/optimizer/prep/prepqual.c
index 8d92ee317a..de72ad8141 100644
--- a/src/backend/optimizer/prep/prepqual.c
+++ b/src/backend/optimizer/prep/prepqual.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/prepqual.c,v 1.48 2004/12/31 22:00:20 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/prep/prepqual.c,v 1.48.4.1 2005/07/29 21:40:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -335,9 +335,10 @@ push_nots(Expr *qual)
 	{
 		/*
 		 * Another NOT cancels this NOT, so eliminate the NOT and stop
-		 * negating this branch.
+		 * negating this branch.  But search the subexpression for more
+		 * NOTs to simplify.
 		 */
-		return get_notclausearg(qual);
+		return find_nots(get_notclausearg(qual));
 	}
 	else
 	{