This section produces "invalid SQL query", I can't seem to figure out why? I have been unable to get this process to work CREATE OR REPLACE FUNCTION schedule_jobs() RETURNS VOID AS $$ BEGIN -- Schedule retry job SELECT cron.schedule( 'retry_failed_jobs' , '*/10 * * * *' , $$ SELECT retry_failed_jobs(); $$ ); -- Schedule first job PERFORM cron.schedule( 'process_current_jobs_if_unlocked_job_1' , '* * * * *' , $$ SELECT process_current_jobs_if_unlocked(); $$ ); -- Schedule second job with a 20-second delay PERFORM pg_sleep( 20 ); PERFORM cron.schedule( 'process_current_jobs_if_unlocked_job_2' , '* * * * *' , $$ SELECT process_current_jobs_if_unlocked(); $$ ); -- Schedule third job with another 20-second delay PERFORM pg_sleep( 20 ); PERFORM cron.schedule( 'process_current_jobs_if_unlocked_job_3' , '* * * * *' , $$ SELECT process_current_jobs_if_unlocked(); $$ ); END ; $$ LANGUAGE plpgsql;