How to see active connections and "current activity" in PostgreSQL 8.4

Question

I'm investigating an issue with DB connections being left open indefinitely, causing problems on the DB server. How do I see currently open connections to a PostgreSQL server, particularly those using a specific database? Ideally I'd like to see what command is executing there as well. Basically, I'm looking for something equivalent to the "Current Activity" view in MSSQL.

Answer 1

OK, got it from someone else. This query should do the trick:

select *
from pg_stat_activity
where datname = 'mydatabasename';

Answer 2

See also pg-top, which acts like top except it shows postgres activity.

• Install pg-top (in Debian, the package is called "ptop").
• Become the postgres user (e.g. sudo su postgres)
• Run pg_top

Answer 3

Reference taken from this article.

SELECT 
    pid
    ,datname
    ,usename
    ,application_name
    ,client_hostname
    ,client_port
    ,backend_start
    ,query_start
    ,query  
FROM pg_stat_activity
WHERE state <> 'idle'
AND pid<>pg_backend_pid();

Answer 4

Two ways to monitor in Ubuntu 18.04, just for reference

One using pg_top:

$ sudo apt-get install ptop
$ pg_top # similar to top as others mentioned

Two using pgAdmin4:

$ sudo apt-get install pgadmin4 pgadmin4-apache2
# type in password and use default url
$ pgadmin4

In the dashboard, check the total/active as

Answer 5

PostgreSQL ASH Viewer (PASH Viewer) provides graphical view of active session history data. https://github.com/dbacvetkov/PASH-Viewer It's free and open source.

ScreenShot

Answer 6

DBeaver is also showing the active/idle/total server sessions very nicely.