Eliminar bloqueos sin un pid en postgres

intenta identificar quién te bloquea exactamente con esta declaración :

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,
         blocked_activity.application_name AS blocked_application,
         blocking_activity.application_name AS blocking_application
   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;

blocking_pid es pid que desea terminar

Puede verificar si su estado de cuenta está bloqueado por smbd con una consulta más corta:

t=# select datname,pid,usename,query from pg_stat_activity where waiting ;
 datname |  pid  | usename  |        query
---------+-------+----------+---------------------
 t       | 30930 | postgres | select * from so24;
(1 row)

Actualización:para la espera de la columna 9.6 era reemplazado con wait_event y wait_event_type, por lo que la consulta será

select datname,pid,usename,query from pg_stat_activity where wait_event is not null;