Here we show how to learn if a certain database user is currently connected to database.
Make sure that you are logged in as a superuser.
Issue the following query to see if the user
bob is connected:
SELECT datname FROM pg_stat_activity WHERE usename = 'bob';
If this query returns any rows, then database user
bob is connected to database. The returned value is the name of the database to which the user is connected.
PostgreSQL system view
pg_stat_activity keeps a track of all running PostgreSQL backends, including what queries are running, who is connected and when they were connected, and when the current transaction and current query were started.
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