From 964ec46cfe95028ca166dd5579e07b22c7434a91 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 1 Jun 2007 23:43:11 +0000
Subject: [PATCH] Fix aboriginal bug in BufFileDumpBuffer that would cause it
 to write the wrong data when dumping a bufferload that crosses a
 component-file boundary. This probably has not been seen in the wild because
 (a) component files are normally 1GB apiece and (b) non-block-aligned buffer
 usage is relatively rare.  But it's fairly easy to reproduce a problem if one
 reduces RELSEG_SIZE in a test build.  Kudos to Kurt Harriman for spotting the
 bug.

---
 src/backend/storage/file/buffile.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/backend/storage/file/buffile.c b/src/backend/storage/file/buffile.c
index ccaed0efa06..4f3a8a311bf 100644
--- a/src/backend/storage/file/buffile.c
+++ b/src/backend/storage/file/buffile.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/file/buffile.c,v 1.25 2007/01/05 22:19:37 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/file/buffile.c,v 1.26 2007/06/01 23:43:11 tgl Exp $
  *
  * NOTES:
  *
@@ -289,7 +289,7 @@ BufFileDumpBuffer(BufFile *file)
 				return;			/* seek failed, give up */
 			file->offsets[file->curFile] = file->curOffset;
 		}
-		bytestowrite = FileWrite(thisfile, file->buffer, bytestowrite);
+		bytestowrite = FileWrite(thisfile, file->buffer + wpos, bytestowrite);
 		if (bytestowrite <= 0)
 			return;				/* failed to write */
 		file->offsets[file->curFile] += bytestowrite;
-- 
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