For wal_consistency_checking, mask page checksum as well as page LSN.

robertmhaas · robertmhaas · commit 6a2fa09c0cba · 2017-09-22T14:28:22.000-04:00
If the LSN is different, the checksum will be different, too. Ashwin Agrawal, reviewed by Michael Paquier and Kuntal Ghosh Discussion: http://postgr.es/m/CALfoeis5iqrAU-+JAN+ZzXkpPr7+-0OAGv7QUHwFn=-wDy4o4Q@mail.gmail.com
diff --git a/src/backend/access/brin/brin_xlog.c b/src/backend/access/brin/brin_xlog.c
@@ -332,7 +332,7 @@ brin_mask(char *pagedata, BlockNumber blkno)
 {
 	Page		page = (Page) pagedata;
 
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 
 	mask_page_hint_bits(page);
 
diff --git a/src/backend/access/common/bufmask.c b/src/backend/access/common/bufmask.c
@@ -23,15 +23,17 @@
  * mask_page_lsn
  *
  * In consistency checks, the LSN of the two pages compared will likely be
- * different because of concurrent operations when the WAL is generated
- * and the state of the page when WAL is applied.
+ * different because of concurrent operations when the WAL is generated and
+ * the state of the page when WAL is applied. Also, mask out checksum as
+ * masking anything else on page means checksum is not going to match as well.
  */
 void
-mask_page_lsn(Page page)
+mask_page_lsn_and_checksum(Page page)
 {
 	PageHeader	phdr = (PageHeader) page;
 
 	PageXLogRecPtrSet(phdr->pd_lsn, (uint64) MASK_MARKER);
+	phdr->pd_checksum = MASK_MARKER;
 }
 
 /*
diff --git a/src/backend/access/gin/ginxlog.c b/src/backend/access/gin/ginxlog.c
@@ -770,7 +770,7 @@ gin_mask(char *pagedata, BlockNumber blkno)
 	Page		page = (Page) pagedata;
 	GinPageOpaque opaque;
 
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 	opaque = GinPageGetOpaque(page);
 
 	mask_page_hint_bits(page);
diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c
@@ -352,14 +352,14 @@ gist_mask(char *pagedata, BlockNumber blkno)
 {
 	Page		page = (Page) pagedata;
 
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 
 	mask_page_hint_bits(page);
 	mask_unused_space(page);
 
 	/*
 	 * NSN is nothing but a special purpose LSN. Hence, mask it for the same
-	 * reason as mask_page_lsn.
+	 * reason as mask_page_lsn_and_checksum.
 	 */
 	GistPageSetNSN(page, (uint64) MASK_MARKER);
 
diff --git a/src/backend/access/hash/hash_xlog.c b/src/backend/access/hash/hash_xlog.c
@@ -1263,7 +1263,7 @@ hash_mask(char *pagedata, BlockNumber blkno)
 	HashPageOpaque opaque;
 	int			pagetype;
 
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 
 	mask_page_hint_bits(page);
 	mask_unused_space(page);
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
@@ -9166,7 +9166,7 @@ heap_mask(char *pagedata, BlockNumber blkno)
 	Page		page = (Page) pagedata;
 	OffsetNumber off;
 
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 
 	mask_page_hint_bits(page);
 	mask_unused_space(page);
diff --git a/src/backend/access/nbtree/nbtxlog.c b/src/backend/access/nbtree/nbtxlog.c
@@ -1034,7 +1034,7 @@ btree_mask(char *pagedata, BlockNumber blkno)
 	Page		page = (Page) pagedata;
 	BTPageOpaque maskopaq;
 
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 
 	mask_page_hint_bits(page);
 	mask_unused_space(page);
diff --git a/src/backend/access/spgist/spgxlog.c b/src/backend/access/spgist/spgxlog.c
@@ -1034,7 +1034,7 @@ spg_mask(char *pagedata, BlockNumber blkno)
 {
 	Page		page = (Page) pagedata;
 
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 
 	mask_page_hint_bits(page);
 
diff --git a/src/backend/access/transam/generic_xlog.c b/src/backend/access/transam/generic_xlog.c
@@ -541,7 +541,7 @@ generic_redo(XLogReaderState *record)
 void
 generic_mask(char *page, BlockNumber blkno)
 {
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 
 	mask_unused_space(page);
 }
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
@@ -1941,7 +1941,7 @@ ResetSequenceCaches(void)
 void
 seq_mask(char *page, BlockNumber blkno)
 {
-	mask_page_lsn(page);
+	mask_page_lsn_and_checksum(page);
 
 	mask_unused_space(page);
 }
diff --git a/src/include/access/bufmask.h b/src/include/access/bufmask.h
@@ -23,7 +23,7 @@
 /* Marker used to mask pages consistently */
 #define MASK_MARKER		0
 
-extern void mask_page_lsn(Page page);
+extern void mask_page_lsn_and_checksum(Page page);
 extern void mask_page_hint_bits(Page page);
 extern void mask_unused_space(Page page);
 extern void mask_lp_flags(Page page);

Original file line number	Diff line number	Diff line change
`@@ -332,7 +332,7 @@ brin_mask(char *pagedata, BlockNumber blkno)`
`332`	`332`	`{`
`333`	`333`	`Page page = (Page) pagedata;`
`334`	`334`
`335`		`- mask_page_lsn(page);`
	`335`	`+ mask_page_lsn_and_checksum(page);`
`336`	`336`
`337`	`337`	`mask_page_hint_bits(page);`
`338`	`338`
Original file line number	Diff line number	Diff line change
`@@ -23,15 +23,17 @@`
`23`	`23`	`* mask_page_lsn`
`24`	`24`	`*`
`25`	`25`	`* In consistency checks, the LSN of the two pages compared will likely be`
`26`		`- * different because of concurrent operations when the WAL is generated`
`27`		`- * and the state of the page when WAL is applied.`
	`26`	`+ * different because of concurrent operations when the WAL is generated and`
	`27`	`+ * the state of the page when WAL is applied. Also, mask out checksum as`
	`28`	`+ * masking anything else on page means checksum is not going to match as well.`
`28`	`29`	`*/`
`29`	`30`	`void`
`30`		`-mask_page_lsn(Page page)`
	`31`	`+mask_page_lsn_and_checksum(Page page)`
`31`	`32`	`{`
`32`	`33`	`PageHeader phdr = (PageHeader) page;`
`33`	`34`
`34`	`35`	`PageXLogRecPtrSet(phdr->pd_lsn, (uint64) MASK_MARKER);`
	`36`	`+ phdr->pd_checksum = MASK_MARKER;`
`35`	`37`	`}`
`36`	`38`
`37`	`39`	`/*`
Original file line number	Diff line number	Diff line change
`@@ -1034,7 +1034,7 @@ spg_mask(char *pagedata, BlockNumber blkno)`
`1034`	`1034`	`{`
`1035`	`1035`	`Page page = (Page) pagedata;`
`1036`	`1036`
`1037`		`- mask_page_lsn(page);`
	`1037`	`+ mask_page_lsn_and_checksum(page);`
`1038`	`1038`
`1039`	`1039`	`mask_page_hint_bits(page);`
`1040`	`1040`
Original file line number	Diff line number	Diff line change
`@@ -541,7 +541,7 @@ generic_redo(XLogReaderState *record)`
`541`	`541`	`void`
`542`	`542`	`generic_mask(char *page, BlockNumber blkno)`
`543`	`543`	`{`
`544`		`- mask_page_lsn(page);`
	`544`	`+ mask_page_lsn_and_checksum(page);`
`545`	`545`
`546`	`546`	`mask_unused_space(page);`
`547`	`547`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1941,7 +1941,7 @@ ResetSequenceCaches(void)`
`1941`	`1941`	`void`
`1942`	`1942`	`seq_mask(char *page, BlockNumber blkno)`
`1943`	`1943`	`{`
`1944`		`- mask_page_lsn(page);`
	`1944`	`+ mask_page_lsn_and_checksum(page);`
`1945`	`1945`
`1946`	`1946`	`mask_unused_space(page);`
`1947`	`1947`	`}`