Question & Answer
Why is my CICS Transaction Server for z/OS (CICS TS) region reaching the Maxtask limit and experiencing very slow response times due to TASKs in ICWAITs? Task are being placed in ICWAITs due to EXEC CICS DELAY requests. I am using ADABAS DATABASE MANAGEMENT SYSTEM from Software AG.
Looking at the system dump, if you enter IPCS command VERBX DFHPD700 'DS=1' (where "700" is for CICS TS 5.3) to display the Dispatcher domain, you will see many tasks suspended with Resource Type ICWAIT. If a task is waiting on ICWAIT this means the task issued an EXEC CICS DELAY. In this case, the program that is doing the EXEC CICS DELAY SECONDS is CCSDUTL0. This is a Software AG program that is in load module CORKRN.
I can tell from SMF data that the tasks are put into an ICWAIT by an EXEC CICS DELAY for 1 second. Tasks are put into a 1-second delay multiple times. For instance, one task has an IC Delay of 102 seconds, it did a 1-second delay 102 times.
In this case, the ADABAS code in CICS is waiting on something (like a request of the ADABAS server to complete or I/O to complete). After 1 second, the task wakes up, finds that whatever it is waiting on has not completed, and then does another 1-second delay.
If you are seeing similar symptoms, you should contact Software AG for a solution for why CCSDUTL0 is issuing the EXEC CICS DELAY for 1 second multiple times.
CICS/TS CICSTS CICS TS CICS Transaction Server
18 September 2018