An application that commits changes regularly incurs some additional cost because DFSMStvs logs changes. DFSMStvs uses the z/OS® system logger, which keeps log entries in the coupling facility for as long as the size of the log permits.

However, an application that does not commit often enough could cause the log entries to spill from the coupling facility to disk. DFSMStvs regularly trims its system log entries when they are no longer needed after a commit. If a long time passes between commits, the effectiveness of this process is diminished. Should this occur, the cost of logging could rise significantly.

You should plan to review logging activity using the SMF type 88 records produced by the system logger.