Cómo obtener las queries bloqueadas y liberarlas en PostgreSQL

Se debe ejecutar la siguiente consulta sobre la base de datos bloqueada:

SELECT blocked_locks.pid     AS blocked_pid,
         blocked_activity.usename  AS blocked_user,
         blocking_locks.pid     AS blocking_pid,
         blocking_activity.usename AS blocking_user,
         blocked_activity.query    AS blocked_statement,
         blocking_activity.query   AS current_statement_in_blocking_process
FROM  pg_catalog.pg_locks         blocked_locks
JOIN pg_catalog.pg_stat_activity blocked_activity  ON blocked_activity.pid = blocked_locks.pid
JOIN pg_catalog.pg_locks         blocking_locks
        ON blocking_locks.locktype = blocked_locks.locktype
        AND blocking_locks.DATABASE IS NOT DISTINCT FROM blocked_locks.DATABASE
        AND blocking_locks.relation IS NOT DISTINCT FROM blocked_locks.relation
        AND blocking_locks.page IS NOT DISTINCT FROM blocked_locks.page
        AND blocking_locks.tuple IS NOT DISTINCT FROM blocked_locks.tuple
        AND blocking_locks.virtualxid IS NOT DISTINCT FROM blocked_locks.virtualxid
        AND blocking_locks.transactionid IS NOT DISTINCT FROM blocked_locks.transactionid
        AND blocking_locks.classid IS NOT DISTINCT FROM blocked_locks.classid
        AND blocking_locks.objid IS NOT DISTINCT FROM blocked_locks.objid
        AND blocking_locks.objsubid IS NOT DISTINCT FROM blocked_locks.objsubid
        AND blocking_locks.pid != blocked_locks.pid
JOIN pg_catalog.pg_stat_activity blocking_activity ON blocking_activity.pid = blocking_locks.pid
WHERE NOT blocked_locks.GRANTED;

Nos devolverá los siguientes datos:

blocked_pid: id de la query bloqueada
blocked_user: usuario que ejecutó la query bloqueada
blocked_statement: query bloqueada
blocking_pid: id de la query bloqueadora
blocking_user: usuario que ejecutó la query bloqueadora
current_statement_in_blocking_process: query bloqueadora

Para liberar una query bloqueadora, se debe ejecutar la siguiente función de Postgres:

SELECT pg_terminate_backend(pid);

Nota: el pid es el de la query bloqueadora. Dependerá de las sentencias, cual se elimina primero. Se deben de estudiar.