Preventing new connections

In certain emergencies, you may need to lock down a server completely, or just prevent specific users from accessing a database. It’s hard to foresee all the situations where you may need to do this, so we will present a range of options.

How to do it…

Connections can be prevented in several ways, as follows:

1. Pause and resume the session pool. See the Setting up a connection pool recipe, later in this chapter, on controlling connection pools.
2. Stop the server (although this is not recommended)! See the Stopping the server safely and quickly and the Stopping the server in an emergency recipes.
3. Restrict the connections for a specific database to 0 by setting the connection limit to 0:

   ALTER DATABASE foo_db CONNECTION LIMIT 0;
   

   This will limit normal users from connecting to that database, although it will still allow superuser connections.

4. Restrict the connections for a specific...