PostgreSQL provides function to terminate specific session on a server.
Find session ID (pid)
First we will identify the session we want to end. We do it by listing all sessions on the server with this query:
select * from pg_stat_activity;
Result shows active sessions on server.
Now we will use process ID (pid) to kill the session (18765 in our example):
select pg_terminate_backend(pid) from pg_stat_activity where pid = '18765';
PostgreSQL ends session and rolls back all transactions that are associated with it.