Data sharing at the database level with update activity
This type of sharing allows one IMS™ batch or online system to have update access. All other IMS systems must have read-only access.
For full-function databases, uncommitted data can be read. For Fast Path, uncommitted data does not exist, but all of the updates for a transaction might not yet have been written. This can cause invalid pointers to be referenced when Get Next processing is performed.
Normal application program isolation protects the integrity of the updating system. However, you can use IRLM for lock management on an IMS online system. The following figure illustrates an online system with update access sharing data with two batch systems that are authorized for read-only access to the same data.
Figure 1. Example of data
sharing at the database level with update access