Question & Answer
Question
Why am I having problems purging hung tasks in my CICS Transaction Server for z/OS (CICS TS) regions? Purge, Force, and Kill commands result in "DEFERRED" responses. Our monitor shows that the tasks are in an External ECB Wait. The CICS regions have to be cycled to resolve the hung tasks.
I also see this message in the logs:
DFHAP1900 CEMT SET TASK(12345) PURGETYPE(FORCEPURGE) RESP(NORMAL) RESP2(13).
The RESP2(13) response indicates the task is not in a valid state for purging.
Answer
The problems with these hung tasks should be resolved after applying UNICOM MACRO 4 PTF TM01963.
A dump taken while the tasks are hung shows that the tasks have been suspended with EXEC CICS WAIT EXTERNAL requests. The WAIT requests are issued by MACRO4 module XT00DFH1.
The register save areas (RSA) provided by module XT00DFH1 on the EXEC CICS WAIT EXTERNAL requests are being prematurely freed and often reused by other tasks. The RSAs are allocated in shared storage. The ECB list provided for the WAIT EXTERNAL might also be freed or reused. Once this happens, the original task is essentially orphaned -- the task can not be woken up, and it also can not be purged.
Product Synonym
CICS/TS CICSTS CICS TS CICS Transaction Server
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Document Information
Modified date:
18 April 2017
UID
dwa1365450