From ba5f900b3d22ca0dfab923abaab4b331595c96b3 Mon Sep 17 00:00:00 2001
From: Teodor Sigaev <teodor@sigaev.ru>
Date: Tue, 30 Aug 2005 08:48:16 +0000
Subject: [PATCH] Fix missing rows in query update a=.. where a... with GiST
 index on column 'a' Backpatch from 8.0 branch

---
 src/backend/access/gist/gist.c     |  7 ++++--
 src/backend/access/gist/gistget.c  | 18 ++++++++++----
 src/backend/access/gist/gistscan.c | 38 ++++++++++++++++++++----------
 3 files changed, 43 insertions(+), 20 deletions(-)

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index c238ea273e5..950d75abd5d 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gist.c,v 1.96 2002/09/04 20:31:09 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gist.c,v 1.96.2.1 2005/08/30 08:48:16 teodor Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -502,7 +502,7 @@ gistlayerinsert(Relation r, BlockNumber blkno,
 		 * changed beginning from 'child' offset
 		 */
 		if (ret & SPLITED)
-			gistadjscans(r, GISTOP_SPLIT, blkno, child);
+			gistadjscans(r, GISTOP_SPLIT, nblkno, FirstOffsetNumber);
 	}
 
 	ret = INSERTED;
@@ -1437,6 +1437,9 @@ gistnewroot(Relation r, IndexTuple *itup, int len)
 	Page		p;
 
 	b = ReadBuffer(r, GISTP_ROOT);
+
+	gistadjscans(r, GISTOP_SPLIT, GISTP_ROOT, FirstOffsetNumber);
+
 	GISTInitBuffer(b, 0);
 	p = BufferGetPage(b);
 
diff --git a/src/backend/access/gist/gistget.c b/src/backend/access/gist/gistget.c
index 2f5801fe781..b10228f18e5 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
- *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gistget.c,v 1.35 2002/09/04 20:31:09 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gistget.c,v 1.35.2.1 2005/08/30 08:48:16 teodor Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -167,10 +167,18 @@ gistnext(IndexScanDesc s, ScanDirection dir)
 			maxoff = PageGetMaxOffsetNumber(p);
 			po = (GISTPageOpaque) PageGetSpecialPointer(p);
 
-			if (ScanDirectionIsBackward(dir))
-				n = OffsetNumberPrev(stk->gs_child);
-			else
-				n = OffsetNumberNext(stk->gs_child);
+			if ( stk->gs_child == InvalidOffsetNumber ) { 
+				/* rescan page */
+				if (ScanDirectionIsBackward(dir))
+					n = PageGetMaxOffsetNumber(p);
+				else
+					n = FirstOffsetNumber;
+			} else {
+				if (ScanDirectionIsBackward(dir))
+					n = OffsetNumberPrev(stk->gs_child);
+				else
+					n = OffsetNumberNext(stk->gs_child);
+			}
 			so->s_stack = stk->gs_parent;
 			pfree(stk);
 
diff --git a/src/backend/access/gist/gistscan.c b/src/backend/access/gist/gistscan.c
index 9c1c92a880a..c8d07916ebd 100644
--- a/src/backend/access/gist/gistscan.c
+++ b/src/backend/access/gist/gistscan.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gistscan.c,v 1.43 2002/06/20 20:29:24 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gistscan.c,v 1.43.2.1 2005/08/30 08:48:16 teodor Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -24,7 +24,7 @@ static void gistregscan(IndexScanDesc s);
 static void gistdropscan(IndexScanDesc s);
 static void gistadjone(IndexScanDesc s, int op, BlockNumber blkno,
 		   OffsetNumber offnum);
-static void adjuststack(GISTSTACK *stk, BlockNumber blkno);
+static void adjuststack(GISTSTACK *stk, int op,BlockNumber blkno, OffsetNumber offnum);
 static void adjustiptr(IndexScanDesc s, ItemPointer iptr,
 		   int op, BlockNumber blkno, OffsetNumber offnum);
 
@@ -319,11 +319,8 @@ gistadjone(IndexScanDesc s,
 
 	so = (GISTScanOpaque) s->opaque;
 
-	if (op == GISTOP_SPLIT)
-	{
-		adjuststack(so->s_stack, blkno);
-		adjuststack(so->s_markstk, blkno);
-	}
+	adjuststack(so->s_stack, op, blkno, offnum);
+	adjuststack(so->s_markstk, op, blkno, offnum);
 }
 
 /*
@@ -405,16 +402,31 @@ adjustiptr(IndexScanDesc s,
  *		access method update code for heaps; if we've modified the tuple we
  *		are looking at already in this transaction, we ignore the update
  *		request.
+ *		If index tuple on our parent stack has been deleted, we need 
+ *		to make step back to avoid miss.
  */
-/*ARGSUSED*/
 static void
-adjuststack(GISTSTACK *stk,
-			BlockNumber blkno)
+adjuststack(GISTSTACK *stk, int op, BlockNumber blkno, OffsetNumber offnum)
 {
-	while (stk != (GISTSTACK *) NULL)
+	while (stk != NULL)
 	{
-		if (stk->gs_blk == blkno)
-			stk->gs_child = FirstOffsetNumber;
+		if (stk->gs_blk == blkno) {
+			switch (op) {
+				case GISTOP_DEL:
+					if ( stk->gs_child >= offnum ) {
+						if ( stk->gs_child > FirstOffsetNumber )
+							stk->gs_child = OffsetNumberPrev( stk->gs_child );
+						else
+							stk->gs_child = InvalidOffsetNumber;
+					}
+					break;
+				case GISTOP_SPLIT:
+					stk->gs_child = InvalidOffsetNumber;
+					break;
+				default:
+					elog(ERROR, "Bad operation in GiST scan adjust: %d", op);
+			}
+		}
 
 		stk = stk->gs_parent;
 	}