Partition definition control blocks and partition definitions in the RECON data set

The online IMS system creates an internal partition definition control block for each HALDB partition that you define.

Any time you change HALDB partition definitions in the RECON data set, IMS must rebuild the partition definition control blocks of all the partitions that are affected by the change before the partitions can be used.

To detect when IMS needs to rebuild a partition definition control block, IMS tracks changes to HALDB databases using a change version number. Each time you change the partition definitions recorded in the RECON data set, DBRC increases the change version number for the HALDB master database by one. When the online IMS system detects an increase in the change version number for a HALDB database, IMS rebuilds the partition definition control block of each partition affected by the change.

Online change is not used to change HALDB partition definitions or rebuild partition definition control blocks. IMS recognizes any increases in HALDB change version numbers and dynamically reflects the new definitions in the online IMS system.

If you are using XRF, the alternate IMS system sees the dynamic change and automatically updates the definitions in the alternate system.