How The Idle Session Timeout Works

How the Idle Session Timeout Works

When the user API call leaves the engine (returns to the calling connection) a special idle timer associated with the current connection is started
When another user API call from that connection enters the engine, the idle timer is stopped and reset to zero
If the maximum idle time is exceeded, the engine immediately closes the connection in the same way as with asynchronous connection cancellation:
- all active statements and cursors are closed
- all active transactions are rolled back
- The network connection remains open at this point, allowing the client application to get the exact error code on the next API call.The network connection will be closed on the server side, after an error is reported or in due course as a result of a network timeout from a client-side disconnection.

Note

Whenever a connection is cancelled, the next user API call returns the error isc_att_shutdown with a secondary error specifying the exact reason.Now, we have

isc_att_shut_idle: Idle timeout expired

in addition to

isc_att_shut_killed: Killed by database administrator
isc_att_shut_db_down: Database is shut down
isc_att_shut_engine: Engine is shut down

Setting the Idle Session Timeout

Note	The idle timer will not start if the timeout period is set to zero.

An idle session timeout can be set:

At database level, the database administrator can set the configuration parameter ConnectionIdleTimeout, an integer value in minutes.The default value of zero means no timeout is set.It is configurable per-database, so it may be set globally in firebird.conf and overridden for individual databases in databases.conf as required.

The scope of this method is all user connections, except system connections (garbage collector, cache writer, etc.).
at connection level, the idle session timeout is supported by both the SET SESSION IDLE TIMEOUT statement and the API (setIdleTimeout).The scope of this method is specific to the supplied connection (attachment).Its value in the API is in seconds.In the SQL syntax it can be hours, minutes or seconds.Scope for this method is the connection to which it is applied.

Note	For more information about the API calls, consult theFirebird 4.0 Release Notes.