Rollback TPS

A Rollback TPS can only have one Tcl proc.

If in a state the Action TPS returns {ERROR $mh}, then DTC calls every Rollback TPS for the current step and all previous steps in reverse order. The DATA message of that step is stored in the staging database as an input argument.

The Rollback TPS should always return {CONTINUE $mh}. $mh is the input DATA message.