Minor fixes for WAL consistency checking.

robertmhaas · robertmhaas · commit fb47544d0ca1 · 2017-02-14T12:41:01.000-05:00
Michael Paquier, reviewed and slightly revised by me. Discussion: http://postgr.es/m/CAB7nPqRzCQb=vdfHvMtP0HMLBHU6z1aGdo4GJsUP-HP8jx+Pkw@mail.gmail.com
diff --git a/src/backend/access/common/bufmask.c b/src/backend/access/common/bufmask.c
@@ -5,7 +5,7 @@
  *	  in a page which can be different when the WAL is generated
  *	  and when the WAL is applied.
  *
- * Portions Copyright (c) 2016, PostgreSQL Global Development Group
+ * Portions Copyright (c) 2016-2017, PostgreSQL Global Development Group
  *
  * Contains common routines required for masking a page.
  *
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
@@ -9167,7 +9167,6 @@ heap_mask(char *pagedata, BlockNumber blkno)
 
 		if (ItemIdIsNormal(iid))
 		{
-
 			HeapTupleHeader page_htup = (HeapTupleHeader) page_item;
 
 			/*
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
@@ -1360,6 +1360,16 @@ checkXLogConsistency(XLogReaderState *record)
 
 		Assert(XLogRecHasBlockImage(record, block_id));
 
+		if (XLogRecBlockImageApply(record, block_id))
+		{
+			/*
+			 * WAL record has already applied the page, so bypass the
+			 * consistency check as that would result in comparing the full
+			 * page stored in the record with itself.
+			 */
+			continue;
+		}
+
 		/*
 		 * Read the contents from the current buffer and store it in a
 		 * temporary page.
@@ -1390,7 +1400,7 @@ checkXLogConsistency(XLogReaderState *record)
 
 		/*
 		 * Read the contents from the backup copy, stored in WAL record and
-		 * store it in a temporary page. There is not need to allocate a new
+		 * store it in a temporary page. There is no need to allocate a new
 		 * page here, a local buffer is fine to hold its contents and a mask
 		 * can be directly applied on it.
 		 */
diff --git a/src/include/access/bufmask.h b/src/include/access/bufmask.h
@@ -7,7 +7,7 @@
  *	  individual rmgr, but we make things easier by providing some
  *	  common routines to handle cases which occur in multiple rmgrs.
  *
- * Portions Copyright (c) 2016, PostgreSQL Global Development Group
+ * Portions Copyright (c) 2016-2017, PostgreSQL Global Development Group
  *
  * src/include/access/bufmask.h
  *

Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,7 @@`
`5`	`5`	`* in a page which can be different when the WAL is generated`
`6`	`6`	`* and when the WAL is applied.`
`7`	`7`	`*`
`8`		`- * Portions Copyright (c) 2016, PostgreSQL Global Development Group`
	`8`	`+ * Portions Copyright (c) 2016-2017, PostgreSQL Global Development Group`
`9`	`9`	`*`
`10`	`10`	`* Contains common routines required for masking a page.`
`11`	`11`	`*`
Original file line number	Diff line number	Diff line change
`@@ -9167,7 +9167,6 @@ heap_mask(char *pagedata, BlockNumber blkno)`
`9167`	`9167`
`9168`	`9168`	`if (ItemIdIsNormal(iid))`
`9169`	`9169`	`{`
`9170`		`-`
`9171`	`9170`	`HeapTupleHeader page_htup = (HeapTupleHeader) page_item;`
`9172`	`9171`
`9173`	`9172`	`/*`
Original file line number	Diff line number	Diff line change
`@@ -7,7 +7,7 @@`
`7`	`7`	`* individual rmgr, but we make things easier by providing some`
`8`	`8`	`* common routines to handle cases which occur in multiple rmgrs.`
`9`	`9`	`*`
`10`		`- * Portions Copyright (c) 2016, PostgreSQL Global Development Group`
	`10`	`+ * Portions Copyright (c) 2016-2017, PostgreSQL Global Development Group`
`11`	`11`	`*`
`12`	`12`	`* src/include/access/bufmask.h`
`13`	`13`	`*`