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commit    a590f266e44c492d2a252ab9dee0cd88dbe06dc5
Author:   Alvaro Herrera <alvherre@alvh.no-ip.org>
Date:     Mon Nov 10 21:13:49 2014 +0000

    BRIN: fix bug in xlog backup block counting
    
    The code that generates the BRIN_XLOG_UPDATE removes the buffer
    reference when the page that's target for the updated tuple is freshly
    initialized.  This is a pretty usual optimization, but was breaking the
    case where the revmap buffer, which is referenced in the same WAL
    record, is getting a backup block: the replay code was using backup
    block index 1, which is not valid when the update target buffer gets
    pruned; the revmap buffer gets assigned 0 instead.  Make sure to use the
    correct backup block index for revmap when replaying.
    
    Bug reported by Fujii Masao.


 src/backend/access/brin/brin_xlog.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/backend/access/brin/brin_xlog.c b/src/backend/access/brin/brin_xlog.c
index ebef984e7f1..29370689a70 100644
--- a/src/backend/access/brin/brin_xlog.c
+++ b/src/backend/access/brin/brin_xlog.c
@@ -60,9 +60,11 @@ brin_xlog_insert_update(XLogRecPtr lsn, XLogRecord *record,
 	 */
 	if (record->xl_info & XLOG_BRIN_INIT_PAGE)
 	{
-		XLogReadBufferForRedoExtended(lsn, record, 0,
-									  xlrec->node, MAIN_FORKNUM, blkno,
-									  RBM_ZERO, false, &buffer);
+		/*
+		 * No full-page image here.  Don't try to read it, because there
+		 * might be one for the revmap buffer, below.
+		 */
+		buffer = XLogReadBuffer(xlrec->node, blkno, true);
 		page = BufferGetPage(buffer);
 		brin_page_init(page, BRIN_PAGETYPE_REGULAR);
 		action = BLK_NEEDS_REDO;
@@ -97,7 +99,9 @@ brin_xlog_insert_update(XLogRecPtr lsn, XLogRecord *record,
 		UnlockReleaseBuffer(buffer);
 
 	/* update the revmap */
-	action = XLogReadBufferForRedo(lsn, record, 1, xlrec->node,
+	action = XLogReadBufferForRedo(lsn, record,
+								   record->xl_info & XLOG_BRIN_INIT_PAGE ? 0 : 1,
+								   xlrec->node,
 								   xlrec->revmapBlk, &buffer);
 	if (action == BLK_NEEDS_REDO)
 	{


[parent: c8df9477f8ce]