An exit is a point at which a user request temporarily leaves the existing code to perform a user-specified task before continuing on with normal processing. You can define routines to perform some function or alteration of normal processing.
You can customize the TDP to perform a user-defined exit routine. Customizing the TDP can assist you in collecting information for performance or functional analysis.
The TDP User Transaction Collection Exit (TDPUTCE) is a routine that allows you to collect statistics about all of the requests and responses that pass through the TDP. TDPUTCE is an exit taken from the Transaction Monitor.