How to select list of active connections to a PostgreSQL database

问题

Is there a command in PostgreSQL to select active connections to a given database?

psql states that I can't drop one of my databases because there are active connections to it, so I would like to see what the connections are (and from which machines)

回答1:

Oh, I just found that command on PostgreSQL forum:

SELECT * FROM pg_stat_activity;

回答2:

Following will give you active connections/ queries in postgres DB-

SELECT 
    pid
    ,datname
    ,usename
    ,application_name
    ,client_hostname
    ,client_port
    ,backend_start
    ,query_start
    ,query
    ,state
FROM pg_stat_activity
WHERE state = 'active'

You may use 'idle' instead of active to get already executed connections/queries.

来源：https://stackoverflow.com/questions/27435839/how-to-select-list-of-active-connections-to-a-postgresql-database