postgresql lock table query

 pid 1 lookup table locks

select pid from pg_locks l join pg_class t on l.relation = t.oid where t.relkind = 'r' and t.relname = 'lockedtable';

2 Find the lock table statement

select pid, state, usename, query, query_start from pg_stat_activity where pid in ( select pid from pg_locks l join pg_class t on l.relation = t.oid and t.relkind = 'r' where t.relname =  'lockedtable');

3 Find all active locked tables

select pid, state, usename, query, query_start 
from pg_stat_activity 
where pid in (
  select pid from pg_locks l 
  join pg_class t on l.relation = t.oid 
  and t.relkind = 'r' 
  
);

4 Unlock

SELECT pg_cancel_backend(pid);

 

 5 batch (not to exclude themselves)

select pg_cancel_backend(pid)
from pg_stat_activity 
where pid in (
  select pid from pg_locks l 
  join pg_class t on l.relation = t.oid 
  and t.relkind = 'r' 
  
);

 

reference:

1 https://jaketrent.com/post/find-kill-locks-postgres/

2 https://www.postgresonline.com/journal/archives/134-Terminating-Annoying-Back-Ends.html