til/postgres/terminating-a-connection.md

Terminating A Connection

Consider the scenario where you are trying to drop a database, but there are existing connections.

$ dropdb sample_db
dropdb: database removal failed: ERROR:  database "sample_db" is being accessed by other users
DETAIL:  There is 1 other session using the database.

If you don't know where these connections are, you can terminate them within a psql session. You just have to figure out the pid of those connections. In List Connections To A Database, I explained how to get at the pid values of connections. Using the pid value and pg_terminate_backend(), you can terminate a connection.

> select pg_terminate_backend(12345);
 pg_terminate_backend
----------------------
 t

To terminate all connections to a particular database, use a query like the following:

select pg_terminate_backend(pg_stat_activity.pid)
from pg_stat_activity
where pg_stat_activity.datname = 'test_drop'
  and pid <> pg_backend_pid();
 pg_terminate_backend
----------------------
 t

This excludes the current session, so you'll need to exit psql as well before dropping the database.

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