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CICS system is in a wait and not getting dispatched

Troubleshooting


Problem

You are running an application that made a EZASOKET call to TCP/IP, and is waiting for a response. This call puts the CICS QR TCB into a wait. The region is not getting dispatched.

Cause

The application is linked with the wrong socket module. See section Hung CICS region in the z/OS Communications Server IP Diagnosis Guide (GC31-8782-11).

Diagnosing The Problem

You can do the following:

  1. Using an MVS system dump of the region, use the IPCS Subcommand ST SYS to format the system status. The local and GMT time of day will be there.

  2. Then format the dump with the CICS verbexit using the 'CSA' keyword. The CICS local time of day will be in the CSA at offset x'50'. You will find that the MVS local time of day is ahead of the CICS time of day.

  3. Format the dump with the CICS verbexit using the 'TR=2'. The last trace entry may be under the quasi reentrant QR TCB. If not, search back up in the trace for an entry made under the QR TCB. Note the TCB address.

  4. Then format the dump with the SUMM FORMAT subcommand, and search for the QR TCB by using the address from the CICS trace. Once it is found, you will find that the top RB will have an OPSW address that is pointing to IEAVEWAT, the MVS wait routine.

    Now page down below the RB structure until you find the LINKAGE STACK ENTRIES. The first linkage stack will contain a PSW with it's address pointing into EZASOCKET. The second linkage stack will contain a PSW with it's address pointing into EZBSOH03. This is the module that requested the MVS wait.

The application requested an EZASOKET call to TCP/IP, and was waiting for a response. It turned out the application was linked with the batch EZASOKET module rather than the CICS version called EZACICAL. Both modules contain a CSECT called EZASOKET so the linkage editor does not encounter any errors with either module. EZACICAL will place the transaction into a wait, while the batch version EZASOKET will place the TCB into an SVC 1 wait.

Resolving The Problem

Relink the application with the EZACICAL module to prevent MVS waits for the QR TCB.

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Product Synonym

CICS/TS CICS TS CICS Transaction Server

Document Information

Modified date:
21 June 2018

UID

swg21054051