PG_TRY_ADVISORY_LOCK

Obtain an exclusive session-level advisory lock without waiting for the lock to become available. This function either obtains the lock immediately and returns true, or returns false if the lock cannot be acquired immediately.

PG_TRY_ADVISORY_LOCK(lock_id)

where lock_id is a BIGINT value.

This function returns a BOOLEAN data type. For example:

premdb=# select pg_try_advisory_lock(32451240);
 pg_try_advisory_lock 
----------------------
 t
(1 row)

Note: Advisory lock functions are not supported in queries with table references in the FROM clause.