查看pg中正在执行的语句

1.背景

有时候代码写的不好，会导致sql性能比较差，比如乱用in_。这时候就需要查看pg中正在执行的语句，看哪些语句执行时间过长。

2.sql语句

select pid,
       datname,
       usename,
       client_addr,
       application_name,
       state,
       backend_start,
       xact_start,
       xact_stay,
       query_start,
       query_stay,
       replace(query, chr(10), ' ') as query
from
  (select pgsa.pid as pid,
          pgsa.datname as datname,
          pgsa.usename as usename,
          pgsa.client_addr client_addr,
          pgsa.application_name as application_name,
          pgsa.state as state,
          pgsa.backend_start as backend_start,
          pgsa.xact_start as xact_start,
          extract(epoch
                  from (now() - pgsa.xact_start)) as xact_stay,
          pgsa.query_start as query_start,
          extract(epoch
                  from (now() - pgsa.query_start)) as query_stay,
          pgsa.query as query
   from pg_stat_activity as pgsa
   where pgsa.state != 'idle'
     and pgsa.state != 'idle in transaction'
     and pgsa.state != 'idle in transaction (aborted)') idleconnections
order by query_stay desc;