diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 6f972be0d7f..e6eb7075d0b 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -2633,7 +2633,7 @@ dblink_res_error(const char *conname, PGresult *res, const char *dblink_context_
 	ereport(level,
 			(errcode(sqlstate),
 			 message_primary ? errmsg_internal("%s", message_primary) :
-			 errmsg("unknown error"),
+			 errmsg("could not obtain message string for remote error"),
 			 message_detail ? errdetail_internal("%s", message_detail) : 0,
 			 message_hint ? errhint("%s", message_hint) : 0,
 			 message_context ? errcontext("%s", message_context) : 0,