Today I Learned

hashrocket A Hashrocket project

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);

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

select pg_terminate_backend(
from pg_stat_activity
where pg_stat_activity.datname = 'sample_db'
  and pid <> pg_backend_pid();

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


See More #sql TILs
Looking for help? Hashrocket developers believe that data quality is as important as code quality. We enjoy all the challenges of relational databases, from finding the fastest index, to structuring data to fit the needs of an application. We're eager to share our experiences; check out PG Casts, our series of free PostgreSQL screencasts.