BUG #16197: pg_advisory_xact_lock error

The following bug has been logged on the website:

Bug reference: 16197
Logged by: andy ye
Email address: andy(dot)ye(at)gtssz(dot)net
PostgreSQL version: 9.5.12
Operating system: ubuntu 16.04
Description:

error log:
2020-01-07 09:45:21 UTC:172.21.1.126(41882):daladmin(at)mobime-pre:[21636]:LOG:
statement: BEGIN
2020-01-07 09:45:21 UTC:172.21.1.126(41882):daladmin(at)mobime-pre:[21636]:LOG:
statement: SELECT pg_advisory_xact_lock(10006, 498408);
2020-01-07 15:43:14 UTC:172.21.1.126(41882):daladmin(at)mobime-pre:[21636]:LOG:
duration: 21472423.193 ms

Hello:
I found that the official documentation seems to introduce very little about
pg_advisory_xact_lock. When I check the postgresql log, I find that it can't
acquire the lock for a long time. Does this mean that the last lock was not
released or not released completely? At present I may need some help:
1. View the SQL that exists in the database pg_advisory_xact_lock and the
SQL that was manually released
2. Corresponds to the fact that I have not obtained the lock for a long
time. Can I set the lock lifetime and automatically release it for a long
time without release, that is, if the lock has not been released for a long
time last time, it will not affect the acquisition of the next lock. What
should I do? Do, since the official documentation is less, I need your
help
Sincere thanks
Dear's Andy