Collecting data about ESAF and DB2 ESS interface problems

ESAF (External Subsystem Attach Facility) interface problems can be diagnosed by using the external trace data set. You can use the IMS /TRACE command to direct and control the tracing of internal IMS events.

The IMS external subsystem (ESS) trace impacts performance. Activate the trace only when you notice a problem or if you need to re-create a problem. IBM® software support may ask you to provide dumps of IMS CTL, z/OS® SVC and the IMS online log data set.

To document problems that involve the Db2 for z/OS ESS interface:

Procedure

  1. Use the following TRACE command to turn on the IMS ESS trace and to direct its output to the external trace data set:
    /TRACE SET ON TABLE SUBS OPTION LOG
  2. Obtain dumps of the IMS CTL and involved dependent regions, before and after the failure, by issuing this series of commands:
    DUMP COMM=(dump title)
    R id JOBNAME=(j1,j2,j3,j4,j5),
    SDATA=(CSA,PSA,RGN,SQA,SUM,TRT),END
  3. Obtain a z/OS SVC dump of the DB2® MSTR and DBM1 regions by issuing this series of commands:
    DUMP COMM=(dump title)
    R id JOBNAME=(dbtmstr,dbwdbm1),
    SDATA=(CSA,PSA,RGN,SQA,SUM,TRT),END
  4. Save the IMS online log data set that was active during the failure because IMS TYPE5501, 08, 07, 56 and other log records can be critical to diagnosis. The IMS TYPE5501 records are updated by DB2. The internal buffer for these records is stored at the location described by the CDE entry named WAL in the IMS regions.
  5. If the IMS monitor is started, issue the following command to monitor the IMS data set:
    /TRACE SET ON MONITOR ALL