A transaction can time-out if the adapter does not receive a Adapter::endTransaction event within a certain amount of time after the receipt of a Adapter::beginTransaction event. If a transaction times out, the adapter will rollback the transaction, causing an error to be returned from the first request event (not the Adapter::beginTransaction event).

If an adapter is shut down before the time-out interval expires and then is restarted, it may reset the time-out interval.

The time-out interval is defined when the adapter is configured. For more information, refer to the documentation for the particular adapter you are using.