diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 009b877e471..b6d6c553d05 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -2707,7 +2707,7 @@ 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,
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 116be7ddcb7..12f736e403a 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -496,7 +496,7 @@ pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 		ereport(elevel,
 				(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,