When you recover a real-time session, the Integration Service reads and processes the cached messages. After the Integration Service reads all cached messages, it ends the session.
For sessions with JMS and WebSphere MQ sources, the Integration Service uses the message ID in the recovery file to retrieve the message from the source.
The Integration Service clears the recovery file after the flush latency period expires and at the end of a successful session. If the session fails after the Integration Service commits messages to the target but before it removes the messages from the recovery file, targets can receive duplicate rows during recovery.