Inconsistent behaviour calling pg_try_advisory_xact_lock with sub-query and when JOIN'ing

Hi all.
 
The following query returns and locks 1 row as expected (only one row in
pg_locks with locktype='advisory' and objid=sequence_id):
 
begin; select qe.entity_id, qe.version, qe.queue_id, qe.sequence_id, qe.tx_id
fromorigo_queue_entry qe WHERE qe.queue_id = (SELECT q.entity_id FROM
origo_queue qWHERE q.name = 'EMAIL_IMPORT_STORE') AND pg_try_advisory_xact_lock(
sequence_id) ORDER BY qe.sequence_id ASC LIMIT 1 FOR UPDATE ;  
But when JOIN'ing with origo_queue instead of using a sub-query:
 
begin; select qe.entity_id, qe.version, qe.queue_id, qe.sequence_id, qe.tx_id
fromorigo_queue_entry qe JOIN origo_queue q ON q.entity_id = qe.queue_id WHERE
q.name = 'EMAIL_IMPORT_STORE' AND pg_try_advisory_xact_lock(sequence_id) ORDER
BYqe.sequence_id ASC LIMIT 1 FOR UPDATE ;  
it returns 1 row, but locks all of them; pg_locks is now full af
advisory-locks for all "sequence_id" in origo_queue_entry

 
Is this by design?
 
Thanks.

 
-- Andreas Joseph Krogh
CTO / Partner - Visena AS
Mobile: +47 909 56 963
andreas(at)visena(dot)com <mailto:andreas(at)visena(dot)com>
www.visena.com <https://www.visena.com>
<https://www.visena.com>