Force client disconnect using PostgreSQL

Question

Is there a way to force clients to disconnect from PostgreSQL? I\'m looking for the equivlent of DB2\'s force application all.

I\'d like to do this on my development

Answer 1

I post my answer because I couldn't use any of them in my script, server 9.3:

psql -U postgres -c "SELECT pid, (SELECT pg_terminate_backend(pid)) as killed from pg_stat_activity WHERE datname = 'my_database_to_alter';"

In the next line, you can do anything yo want with 'my_database_to_alter'. As you can see, yo perform the query from the "postgres" database, which exists almost in every postgresql installation.

Doing by superuser and outside the problem-database itself worked perfect for me.

Answer 2

Kills idle processes in PostgreSQL 8.4:

SELECT procpid, (SELECT pg_terminate_backend(procpid)) as killed from pg_stat_activity
   WHERE current_query LIKE '<IDLE>';

Answer 3

probably a more heavy handed approach then should be used but:

for x in `ps -eF | grep -E "postgres.*idle"| awk '{print $2}'`;do kill $x; done

Answer 4

Combine pg_terminate_backend function and the pg_stat_activity system view.

Answer 5

I found this thread on the mailing list. It suggests using SIGTERM to cause the clients to disconnect.

Not as clean as db2 force application all.

Answer 6

This SO answer beautifully explains (full quote from araqnid between the horizontal rules, then me again):

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To mark database 'applogs' as not accepting new connections:

update pg_database set datallowconn = false where datname = 'applogs';

Another possibility would be to revoke 'connect' access on the database for the client role(s).

Disconnect users from database = kill backend. So to disconnect all other users from "applogs" database, for example:

select pg_terminate_backend(procpid)
from pg_stat_activity
where datname = 'applogs' and procpid <> pg_backend_pid();

Once you've done both of those, you are the only user connected to 'applogs'. Although there might actually be a delay before the backends actually finish disconnecting?

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Update from MarkJL: There is indeed a delay before the backends finish disconnecting.

Now me again: That being said, mind that the procpid column was renamed to pid in PostgreSQL 9.2 and later.

I think that this is much more helpful than the answer by Milen A. Radev which, while technically the same, does not come with usage examples and real-life suggestions.