POSTGRESQL 锁表的问题详解数据库

select 
    wait.pid, 
    wait.query as wait_query, 
    wait.query_start as wait_query_start, 
    wait.locktype, 
    granted.pid as waitfor_pid, 
    granted.relation, 
    granted.datname || '.' || d.nspname || '.' || c.relname as name, 
    granted.transactionid, 
    granted.virtualxid, 
    granted.usename, 
    granted.client_addr, 
    granted.query_start, 
    granted.query 
from 
    (select 
          a.query, 
          a.query_start, 
          b.pid, 
          b.relation, 
          b.transactionid, 
          b.page, 
          b.tuple, 
          b.locktype, 
          b.virtualxid 
     from 
          pg_stat_activity a, 
          pg_locks b 
     where 
          a.waiting = 't' 
          and a.pid = b.pid 
          and granted = 'f' 
    ) wait 
join 
    (select 
        b.pid, 
        b.usename, 
        b.client_addr, 
        b.backend_start, 
        b.query_start, 
        b.waiting, 
        b.query, 
        b.datname, 
        a.relation, 
        a.transactionid, 
        a.page, 
        a.tuple, 
        a.locktype, 
        a.virtualxid 
    from 
        pg_locks a, 
        pg_stat_activity b 
    where 
        a.pid = b.pid 
        and a.granted = 't' 
    ) granted 
on ( 
    ( wait.locktype = 'transactionid' 
    and granted.locktype = 'transactionid' 
    and wait.transactionid = granted.transactionid ) 
    or 
    ( wait.locktype = 'relation' 
    and granted.locktype = 'relation' 
    and wait.relation = granted.relation 
    ) 
    or 
    ( wait.locktype = 'virtualxid' 
    and granted.locktype = 'virtualxid' 
    and wait.virtualxid = granted.virtualxid ) 
    or 
    ( wait.locktype = 'tuple' 
    and granted.locktype = 'tuple' 
    and wait.relation = granted.relation 
    and wait.page = granted.page 
    and wait.tuple = granted.tuple ) 
) 
left join 
    pg_class c 
on ( c.relfilenode = wait.relation ) 
left join 
    pg_namespace d 
on ( c.relnamespace = d.oid ) 
order by 
granted.query_start 
;

select pg_terminate_backend(进程id)