Properly access a buffer's LSN using existing access macros instead of abusing

alvherre · alvherre · commit 089ae3bc9aa2 · 2008-10-20T21:11:15.000Z
knowledge of page layout.

Stolen from Jonah Harris' CRC patch
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.238 2008/09/17 13:15:55 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.239 2008/10/20 21:11:15 alvherre Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -48,7 +48,7 @@
 
 /* Note: these two macros only work on shared buffers, not local ones! */
 #define BufHdrGetBlock(bufHdr)	((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))
-#define BufferGetLSN(bufHdr)	(*((XLogRecPtr*) BufHdrGetBlock(bufHdr)))
+#define BufferGetLSN(bufHdr)	(PageGetLSN(BufHdrGetBlock(bufHdr)))
 
 /* Note: this macro only works on local buffers, not shared ones! */
 #define LocalBufHdrGetBlock(bufHdr) \

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.238 2008/09/17 13:15:55 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/storage/buffer/bufmgr.c,v 1.239 2008/10/20 21:11:15 alvherre Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -48,7 +48,7 @@`
`48`	`48`
`49`	`49`	`/* Note: these two macros only work on shared buffers, not local ones! */`
`50`	`50`	`#define BufHdrGetBlock(bufHdr) ((Block) (BufferBlocks + ((Size) (bufHdr)->buf_id) * BLCKSZ))`
`51`		`-#define BufferGetLSN(bufHdr) (((XLogRecPtr) BufHdrGetBlock(bufHdr)))`
	`51`	`+#define BufferGetLSN(bufHdr) (PageGetLSN(BufHdrGetBlock(bufHdr)))`
`52`	`52`
`53`	`53`	`/* Note: this macro only works on local buffers, not shared ones! */`
`54`	`54`	`#define LocalBufHdrGetBlock(bufHdr) \`