diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 3a0beaa88e7..824d301aad8 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -2799,7 +2799,8 @@ dblink_res_error(PGconn *conn, const char *conname, PGresult *res,
 
 	ereport(level,
 			(errcode(sqlstate),
-			 message_primary ? errmsg_internal("%s", message_primary) :
+			 (message_primary != NULL && message_primary[0] != '\0') ?
+			 errmsg_internal("%s", message_primary) :
 			 errmsg("could not obtain message string for remote error"),
 			 message_detail ? errdetail_internal("%s", message_detail) : 0,
 			 message_hint ? errhint("%s", message_hint) : 0,
diff --git a/contrib/postgres_fdw/connection.c b/contrib/postgres_fdw/connection.c
index 03c7843f15b..1c7c76d1d4c 100644
--- a/contrib/postgres_fdw/connection.c
+++ b/contrib/postgres_fdw/connection.c
@@ -805,7 +805,8 @@ pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
 
 		ereport(elevel,
 				(errcode(sqlstate),
-				 message_primary ? errmsg_internal("%s", message_primary) :
+				 (message_primary != NULL && message_primary[0] != '\0') ?
+				 errmsg_internal("%s", message_primary) :
 				 errmsg("could not obtain message string for remote error"),
 				 message_detail ? errdetail_internal("%s", message_detail) : 0,
 				 message_hint ? errhint("%s", message_hint) : 0,