Print WAL position correctly in pg_rewind error message.

hlinnaka · hlinnaka · commit d8b094dabb0f · 2019-07-30T21:14:14.000+03:00
This has been wrong ever since pg_rewind was added. The if-branch just
above this, where we print the same error with an extra message supplied
by XLogReadRecord() got this right, but the variable name was wrong in the
else-branch. As a consequence, the error printed the WAL position as
0/0 if there was an error reading a WAL file.

Backpatch to 9.5, where pg_rewind was added.
diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c
@@ -89,8 +89,7 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex,
 						 errormsg);
 			else
 				pg_fatal("could not read WAL record at %X/%X",
-						 (uint32) (startpoint >> 32),
-						 (uint32) (startpoint));
+						 (uint32) (errptr >> 32), (uint32) (errptr));
 		}
 
 		extractPageInfo(xlogreader);

Original file line number	Diff line number	Diff line change
`@@ -89,8 +89,7 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex,`
`89`	`89`	`errormsg);`
`90`	`90`	`else`
`91`	`91`	`pg_fatal("could not read WAL record at %X/%X",`
`92`		`- (uint32) (startpoint >> 32),`
`93`		`- (uint32) (startpoint));`
	`92`	`+ (uint32) (errptr >> 32), (uint32) (errptr));`
`94`	`93`	`}`
`95`	`94`
`96`	`95`	`extractPageInfo(xlogreader);`