Use the PowerExchange Logger to log all PowerExchange activity.
You do not normally restore the PowerExchange Logger.
When you restore the source database because of application failures, you typically reset the application extraction start points to the relevant point.
To identify the correct point to start, use the Event Marker utility, EDMXLUTL, to put markers into the Logger on a regular basis. When you add these markers, they appear in the PowerExchange log.