You can't concurrently execute queries from within a single connection. Perhaps you should use multiple connections, while understanding the implications of having each operate within a separate snapshot. Don't forget to free memory with PQclear() . I guess you omitted that because it's just pseudo-code. -- Regards, Peter Geoghegan -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general