gtpa2m1gApplication Programming

Checkpoint

All the memory queues and some channel data is filed to fixed file records (#IMQCK) on a regular basis. This is called MQSeries checkpointing. The file copy of the queues and channels, together with the data written to the recovery log, are how The TPF system ensures that all data is made persistent during an IPL of a TPF system. TPF restart will rebuild the queues and channels to exactly the same state as before the IPL by using the fixed file checkpoint with the data found on the recovery log.

The size of the recovery log must be enough to accommodate all logging activity for all TPF resource managers, (not just the TPF MQSeries resource manager) between each successful completed checkpoint. The checkpoint interval is 5 seconds.

Ensure that you have enough fixed file checkpoint records (#IMQCK) to fit all the queues and channel data. See TPF System Generation for information on how to determine the correct number of records to allocate for checkpointing.