These are the commands I have run in the terminal psql (17.0) Type "help" for help.
postgres=# SELECT pg_advisory_lock_shared(1001); //initialising the shared lock pg_advisory_lock_shared ------------------------- (1 row) postgres=# SELECT pg_advisory_lock(1001); //exclusive lock pg_advisory_lock ------------------ (1 row).... now i have logged in session 2 to check whether both locks are granted without conflict, heres the output : postgres=# SELECT * FROM pg_locks WHERE locktype = 'advisory'; locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid | virtualtransaction | pid | mode | granted | fastpath | waitstart ----------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+------+---------------+---------+----------+----------- advisory | 5 | | | | | | 0 | 1001 | 1 | 3/0 | 7126 | ShareLock | t | f | advisory | 5 | | | | | | 0 | 1001 | 1 | 3/0 | 7126 | ExclusiveLock | t | f | (2 rows) UNDERSTANDING : The same resource ( oid and pid) are allocate to both exclusive and shared lock . I am also attaching the screenshots. On Tue, 11 Feb 2025 at 14:01, Álvaro Herrera <alvhe...@alvh.no-ip.org> wrote: > Hello > > On 2025-Feb-11, PG Doc comments form wrote: > > > ISSUE : According to the above paragraph , locks should either be shared > or > > exclusive. But when I tried assigning a shared lock and exclusive lock > > without unlock of the shared lock , it doesn't show a conflict. I think > this > > may contradict what is said in above paragraph of documentation. Can you > > enlighten me more on this , regarding the understanding if my assumption > is > > wrong. > > Your understanding is correct -- there should be a conflict. The lack > of one suggests that you're using the lock interfaces incorrectly. > Please show the exact commands you're running. Maybe there's something > about the documentation text that needs to be made clearer. > > > I could have attached snaps of the same but I don't find an > > attachment option. > > True. You can reply to this email with attachments. However, I would > instead suggest to copy and paste text from terminal window(s), rather > than screenshots. > > -- > Álvaro Herrera PostgreSQL Developer — > https://www.EnterpriseDB.com/ >
