Improve comment explaining how search_next_wal works with LSN

Michael Paquier · Michael Paquier · commit a66e683dd4da · 2013-12-25T08:26:25.000+09:00
This makes the explanation a bit clearer, as the LSN in this function
is used with the current timeline to generate the file name.
diff --git a/restore.c b/restore.c
@@ -1021,7 +1021,12 @@ search_next_wal(const char *path, XLogRecPtr *need_lsn, parray *timelines)
 			parray_remove(timelines, i + 1);
 		/* XXX: should we add a linebreak when we find a timeline? */
 
-		/* Move to next xlog segment */
+		/*
+		 * Move to next xlog segment. Note that we need to increment
+		 * by XLogSegSize to jump directly to the next WAL segment file
+		 * and as this value is used to generate the WAL file name with
+		 * the current timeline of backup.
+		 */
 		*need_lsn += XLogSegSize;
 	}
 }

Original file line number	Diff line number	Diff line change
`@@ -1021,7 +1021,12 @@ search_next_wal(const char path, XLogRecPtr need_lsn, parray *timelines)`
`1021`	`1021`	`parray_remove(timelines, i + 1);`
`1022`	`1022`	`/* XXX: should we add a linebreak when we find a timeline? */`
`1023`	`1023`
`1024`		`- /* Move to next xlog segment */`
	`1024`	`+ /*`
	`1025`	`+ * Move to next xlog segment. Note that we need to increment`
	`1026`	`+ * by XLogSegSize to jump directly to the next WAL segment file`
	`1027`	`+ * and as this value is used to generate the WAL file name with`
	`1028`	`+ * the current timeline of backup.`
	`1029`	`+ */`
`1025`	`1030`	`*need_lsn += XLogSegSize;`
`1026`	`1031`	`}`
`1027`	`1032`	`}`