Question & Answer
Question
Why do I experience response time delays of 15 to 20 seconds in my application transaction whenever a DB2 thread terminates in CICS Transaction Server for z/OS (CICS TS)? I am using BMC MainView and DB2 V11.
The response time delays occur when there are no protected threads defined on the DB2Entry. If I change the DB2Entry to include protected threads, the task ends normally (sub-second). But in this scenario, when the thread is terminated for inactivity under transaction CEX2 (the DB2 protected thread purge mechanism) , I still see that 15-20 second delay.
I can see that the delay is in the DB2 terminate thread by looking at the time stamps in a CICS auxiliary trace that I took when the transaction was experiencing the high response time:
AP 3267 D2D2 EVENT - ABOUT_TO_ISSUE_DB2_TERMINATE_THREAD_FOR_PLAN(PLANNAME)
TASK-17285 KE_NUM-0056 TCB-L800H/009950E0 RET-BC5E04F6 TIME-13:37:33.3718059531
AP 3268 D2D2 EVENT - RETURN_FROM_DB2_TERMINATE_THREAD_FOR_PLAN(PLANNAME)
TASK-17285 KE_NUM-0056 TCB-L800H/009950E0 RET-BC5E04F6 TIME-13:37:53.8644332111
Answer
Looking at the CICS auxiliary and the addresses from the trace in a snap dump taken at the same time reveals that there is a loop in BMC module IODXGQBB that delays DB2 thread termination. A fix was provided as BMC PTF BPU8591 which resolved the response time delays.
A new version of the BMC software was installed just before the application started reporting the long response time for the CICS transaction.
Contact BMC Software if you need additional assistance.
Information APAR II14804 documents APAR BPU8591 as "Those running Mainview with DB2 V11 experiencing intermittent high CPU in the MSTR address space. "
Product Synonym
CICS/TS CICSTS CICS TS CICS Transaction Server
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Document Information
Modified date:
21 June 2016
UID
dwa1283088