Report expected contrecord length on mismatch

alvherre · alvherre · commit f43e295f68c3 · 2020-09-04T14:58:32.000-04:00
When reading a WAL record fails to find continuation record(s) of the proper length, report what it expects, for clarity. Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/20200903212152.GA15319@alvherre.pgsql
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
@@ -464,8 +464,9 @@ XLogReadRecord(XLogReaderState *state, char **errormsg)
 				total_len != (pageHeader->xlp_rem_len + gotlen))
 			{
 				report_invalid_record(state,
-									  "invalid contrecord length %u at %X/%X",
+									  "invalid contrecord length %u (expected %lld) at %X/%X",
 									  pageHeader->xlp_rem_len,
+									  ((long long) total_len) - gotlen,
 									  (uint32) (RecPtr >> 32), (uint32) RecPtr);
 				goto err;
 			}

Original file line number	Diff line number	Diff line change
`@@ -464,8 +464,9 @@ XLogReadRecord(XLogReaderState state, char *errormsg)`
`464`	`464`	`total_len != (pageHeader->xlp_rem_len + gotlen))`
`465`	`465`	`{`
`466`	`466`	`report_invalid_record(state,`
`467`		`- "invalid contrecord length %u at %X/%X",`
	`467`	`+ "invalid contrecord length %u (expected %lld) at %X/%X",`
`468`	`468`	`pageHeader->xlp_rem_len,`
	`469`	`+ ((long long) total_len) - gotlen,`
`469`	`470`	`(uint32) (RecPtr >> 32), (uint32) RecPtr);`
`470`	`471`	`goto err;`
`471`	`472`	`}`