Make multixact error message more explicit

alvherre · alvherre · commit 2cf41cd30997 · 2022-11-24T10:45:10.000+01:00
There are recent reports involving a very old error message that we have no history of hitting -- perhaps a recently introduced bug. Improve the error message in an attempt to improve our chances of investigating the bug. Per reports from Dimos Stamatakis and Bob Krier. Backpatch to 11. Discussion: https://postgr.es/m/CO2PR0801MB2310579F65529380A4E5EDC0E20A9@CO2PR0801MB2310.namprd08.prod.outlook.com Discussion: https://postgr.es/m/17518-04e368df5ad7f2ee@postgresql.org
diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
@@ -799,7 +799,8 @@ MultiXactIdCreateFromMembers(int nmembers, MultiXactMember *members)
 			if (ISUPDATE_from_mxstatus(members[i].status))
 			{
 				if (has_update)
-					elog(ERROR, "new multixact has more than one updating member");
+					elog(ERROR, "new multixact has more than one updating member: %s",
+						 mxid_to_string(InvalidMultiXactId, nmembers, members));
 				has_update = true;
 			}
 		}

Original file line number	Diff line number	Diff line change
`@@ -799,7 +799,8 @@ MultiXactIdCreateFromMembers(int nmembers, MultiXactMember *members)`
`799`	`799`	`if (ISUPDATE_from_mxstatus(members[i].status))`
`800`	`800`	`{`
`801`	`801`	`if (has_update)`
`802`		`- elog(ERROR, "new multixact has more than one updating member");`
	`802`	`+ elog(ERROR, "new multixact has more than one updating member: %s",`
	`803`	`+ mxid_to_string(InvalidMultiXactId, nmembers, members));`
`803`	`804`	`has_update = true;`
`804`	`805`	`}`
`805`	`806`	`}`