From a507b86900f695aacc8d52b7d2cfcb65f58862a2 Mon Sep 17 00:00:00 2001
From: Robert Haas
Date: Wed, 8 Feb 2017 15:45:30 -0500
Subject: Add WAL consistency checking facility.

When the new GUC wal_consistency_checking is set to a non-empty value,
it triggers recording of additional full-page images, which are
compared on the standby against the results of applying the WAL record
(without regard to those full-page images).  Allowable differences
such as hints are masked out, and the resulting pages are compared;
any difference results in a FATAL error on the standby.

Kuntal Ghosh, based on earlier patches by Michael Paquier and Heikki
Linnakangas.  Extensively reviewed and revised by Michael Paquier and
by me, with additional reviews and comments from Amit Kapila, Álvaro
Herrera, Simon Riggs, and Peter Eisentraut.
---
 src/backend/access/brin/brin_xlog.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'src/backend/access/brin/brin_xlog.c')

diff --git a/src/backend/access/brin/brin_xlog.c b/src/backend/access/brin/brin_xlog.c
index b698c9b58c5..f416bacc3f7 100644
--- a/src/backend/access/brin/brin_xlog.c
+++ b/src/backend/access/brin/brin_xlog.c
@@ -13,6 +13,7 @@
 #include "access/brin_page.h"
 #include "access/brin_pageops.h"
 #include "access/brin_xlog.h"
+#include "access/bufmask.h"
 #include "access/xlogutils.h"
 
 
@@ -279,3 +280,22 @@ brin_redo(XLogReaderState *record)
 			elog(PANIC, "brin_redo: unknown op code %u", info);
 	}
 }
+
+/*
+ * Mask a BRIN page before doing consistency checks.
+ */
+void
+brin_mask(char *pagedata, BlockNumber blkno)
+{
+	Page		page = (Page) pagedata;
+
+	mask_page_lsn(page);
+
+	mask_page_hint_bits(page);
+
+	if (BRIN_IS_REGULAR_PAGE(page))
+	{
+		/* Regular brin pages contain unused space which needs to be masked. */
+		mask_unused_space(page);
+	}
+}
-- 
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