Dependent region occupancy and OTMA
A send-then-commit transaction remains in a dependent region while the output is being sent (before a sync point occurs). You can get additional information about a specific dependent region that is in an OTMA-related wait state by using the DISPLAY ACT command.
The following states (from the STATUS response field) indicate that an OTMA-related activity is in progress:
- WAIT-CALLOUT
- WAIT-RRS PC
- WAIT-SYNCPOINT
- TERM-WAIT SYNCPT
- TERM-WAIT RRS
If the region is waiting for a synchronous program switch response, the amount of time remaining before the region times out the request is displayed in the END TIME field of the output from the DISPLAY ACT REGION command.
Recommendations:
- If many of your transactions are send-then-commit (CM1) transactions, increase the number of dependent regions to improve throughput performance.
- For the CM1 messages that use synclevel=confirm or synclevel=syncpt, specify a timeout interval to free dependent regions if an OTMA client does not provide the required ACK or NAK response within a reasonable amount of time.
- Use as many commit-then-send (CM0) OTMA transactions as possible.
