Fix possible duplicate tuples while GiST scan. Now page is processed

at once and ItemPointers are collected in memory.

Remove tuple's killing by killtuple() if tuple was moved to another
page - it could produce unaceptable overhead.

Backpatch up to 8.1 because the bug was introduced by GiST's concurrency support.

1 files changed, 14 insertions, 1 deletions

diff --git a/src/include/access/gist_private.h b/src/include/access/gist_private.h
index 497ceb318ed..e366dcc53e7 100644
--- a/src/include/access/gist_private.h
+++ b/src/include/access/gist_private.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/gist_private.h,v 1.31 2008/06/19 00:46:05 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/access/gist_private.h,v 1.32 2008/08/23 10:37:24 teodor Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -58,6 +58,12 @@ typedef struct GISTSTATE
 	TupleDesc	tupdesc;
 } GISTSTATE;
 
+typedef struct ItemResult
+{
+	ItemPointerData		iptr;
+	bool				recheck;
+} ItemResult;
+
 /*
  *	When we're doing a scan, we need to keep track of the parent stack
  *	for the marked and current items.
@@ -73,6 +79,13 @@ typedef struct GISTScanOpaqueData
 	ItemPointerData curpos;
 	Buffer		markbuf;
 	ItemPointerData markpos;
+
+	ItemResult		pageData[BLCKSZ/sizeof(IndexTupleData)];
+	OffsetNumber	nPageData;
+	OffsetNumber	curPageData;
+	ItemResult		markPageData[BLCKSZ/sizeof(IndexTupleData)];
+	OffsetNumber	markNPageData;
+	OffsetNumber	markCurPageData;
 } GISTScanOpaqueData;
 
 typedef GISTScanOpaqueData *GISTScanOpaque;