 
             DELETE FROM system.job_queue WHERE job_id = result.id;
         END IF;
-
-        PERFORM pg_advisory_unlock(0);
 
         RETURN result;
     ELSE

    result integer;
BEGIN
    -- Acquire locks
    LOCK TABLE system.job IN ACCESS EXCLUSIVE MODE;
    LOCK TABLE system.job_queue IN ACCESS EXCLUSIVE MODE;
    LOCK TABLE transform.state IN ACCESS EXCLUSIVE MODE;

    -- Drop constraints on dependent tables
    ALTER TABLE system.job_queue DROP CONSTRAINT job_queue_job_id_fkey;

DECLARE
    result system.job_type;
BEGIN
    IF pg_try_advisory_xact_lock(0) THEN
        SELECT job.id, job.type, job.description, job.size, js.config INTO result
            FROM system.job_queue
            JOIN system.job ON job_id = id
