From 07bd1db152e95a44722c1fd23572dfeaf8e07eaf Mon Sep 17 00:00:00 2001
From: Teodor Sigaev <teodor@sigaev.ru>
Date: Mon, 4 Jun 2007 15:59:20 +0000
Subject: Fix bundle bugs of GIN: - Fix possible deadlock between UPDATE and
 VACUUM queries. Bug never was   observed in 8.2, but it still exist there.
 HEAD is more sensitive to   bug after recent "ring" of buffer improvements. -
 Fix WAL creation: if parent page is stored as is after split then  
 incomplete split isn't removed during replay. This happens rather rare, only 
  on large tables with a lot of updates/inserts. - Fix WAL replay: there was
 wrong test of XLR_BKP_BLOCK_* for left   page after deletion of page. That
 causes wrong rightlink field: it pointed   to deleted page. - add checking of
 match of clearing incomplete split - cleanup incomplete split list after
 proceeding

All of this chages doesn't change on-disk storage, so backpatch...
But second point may be an issue for replaying logs from previous version.
---
 src/backend/access/gin/ginentrypage.c | 43 +++++++++++++++++++++++------------
 1 file changed, 28 insertions(+), 15 deletions(-)

(limited to 'src/backend/access/gin/ginentrypage.c')

diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index 5dc3ac57b31..ca409666030 100644
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *			$PostgreSQL: pgsql/src/backend/access/gin/ginentrypage.c,v 1.5 2006/11/12 06:55:53 neilc Exp $
+ *			$PostgreSQL: pgsql/src/backend/access/gin/ginentrypage.c,v 1.5.2.1 2007/06/04 15:59:19 teodor Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -354,6 +354,7 @@ entryPlaceToPage(GinBtree btree, Buffer buf, OffsetNumber off, XLogRecData **prd
 	static XLogRecData rdata[3];
 	OffsetNumber placed;
 	static ginxlogInsert data;
+	int 	cnt=0;
 
 	*prdata = rdata;
 	data.updateBlkno = entryPreparePage(btree, page, off);
@@ -371,21 +372,33 @@ entryPlaceToPage(GinBtree btree, Buffer buf, OffsetNumber off, XLogRecData **prd
 	data.isData = false;
 	data.isLeaf = GinPageIsLeaf(page) ? TRUE : FALSE;
 
-	rdata[0].buffer = buf;
-	rdata[0].buffer_std = TRUE;
-	rdata[0].data = NULL;
-	rdata[0].len = 0;
-	rdata[0].next = &rdata[1];
+    /*
+	 * Prevent full page write if child's split occurs. That is needed
+	 * to remove incomplete splits while replaying WAL
+	 *
+	 * data.updateBlkno contains new block number (of newly created right page)
+	 * for recently splited page.
+	 */
+	if ( data.updateBlkno == InvalidBlockNumber ) 
+	{
+		rdata[0].buffer = buf;
+		rdata[0].buffer_std = TRUE;
+		rdata[0].data = NULL;
+		rdata[0].len = 0;
+		rdata[0].next = &rdata[1];
+		cnt++;
+	}
 
-	rdata[1].buffer = InvalidBuffer;
-	rdata[1].data = (char *) &data;
-	rdata[1].len = sizeof(ginxlogInsert);
-	rdata[1].next = &rdata[2];
-
-	rdata[2].buffer = InvalidBuffer;
-	rdata[2].data = (char *) btree->entry;
-	rdata[2].len = IndexTupleSize(btree->entry);
-	rdata[2].next = NULL;
+	rdata[cnt].buffer = InvalidBuffer;
+	rdata[cnt].data = (char *) &data;
+	rdata[cnt].len = sizeof(ginxlogInsert);
+	rdata[cnt].next = &rdata[cnt+1];
+	cnt++;
+
+	rdata[cnt].buffer = InvalidBuffer;
+	rdata[cnt].data = (char *) btree->entry;
+	rdata[cnt].len = IndexTupleSize(btree->entry);
+	rdata[cnt].next = NULL;
 
 	btree->entry = NULL;
 }
-- 
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