diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index ad9e7ff8f05..672818f75ce 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -779,7 +779,8 @@ 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;
 			}
 		}