如何检查PG数据库连接数

一 检查连接数

select

     to_char(now(),'yyyy-mm-dd hh24:mi:ss') "time"

    ,max_conn "max_conn(最大连接数)"

    ,now_conn "now_conn(当前连接数)"

    ,max_conn - now_conn "remain_conn(剩余连接数)"

from (

    select

         setting::int8 as max_conn

        ,(select count(*) from pg_stat_activity ) as now_con