Enhancement for the processing of OTMA commit-then-send messages in shared-queues environments

This enhancement is added to IMS 15 by APAR PH02371.

Previously, when a back-end IMS system sent commit-then-send shared queues messages to a front-end IMS system, it first sent notification messages to the front-end IMS system to notify the presence of the outputs. The OTMA ITASK DFSYMOM0 in the front-end IMS system is used to manage these notification messages. However, when the ITASK was busy with processing shared queues notification messages from a back-end system, other jobs that are processed by the ITASK, such as the creation of transaction pipes (tpipes), could be delayed. This impacted the performance of IMS.

With this enhancement, a new OTMA ITASK DFSYDAD0 is created through OID TCB to separately process OTMA commit-then-send back-end messages in a shared queues environment. As a result, the main OTMA ITASK DFSYMOM0 can focus on other important jobs. This enhancement reduces delays and improves performance.

This enhancement also enhances tpipe flood control. The valid value of the MAXTPRL parameter in OTMA client descriptors and DFSOTMA client descriptors that defines the relief level of the MAXTP value was enhanced to 50 - 95, instead of 50 - 70. A new parameter MAXTPWN is added to OTMA client descriptors and DFSOTMA client descriptors. You can use the MAXTPWN parameter to define a warning threshold as a percentage of the MAXTP value. Before the MAXTP threshold is reached, a warning message DFS4515W is issued. You can specify a value in the range 50 - 95 for the MAXTPWN parameter. That is, the message DFS4515W can be issued before 50% - 95% of the MAXTP value is reached. After you see the warning message DFS4515W, you can remove idle tpipes to prevent tpipes from overflowing so that the IMS system can continue creating new tpipes. If the MAXTPWN value is not specified, the default tpipe flood warning level is 80% of the MAXTP threshold value.

Changes to troubleshooting for IMS

For a complete list of all of the new, changed, and deleted messages, and abend codes in IMS 15, see Message and code changes in IMS 15.

Changes to commands

The /DISPLAY TMEMBER command is enhanced to have SYW status and its description removed.

Documentation changes

The following table lists the publications that contain new or changed topics for the New function name enhancement. Publications that are not impacted by this enhancement are not included in the table.