Analyzing concurrency

You can analyze concurrency for an application that experiences problems with lock contention.

About this task

Begin program-specific programming interface information.In IBM® OMEGAMON® for Db2 Performance Expert on z/OS® , a report titled Trace corresponds to a single Db2 trace record; a report titled Report summarizes information from several trace records.

The example uses the following reports for problem analysis:

  • Accounting report - long
  • Locking suspension report
  • Lockout report
  • Lockout trace

In some cases, the initial and detailed stages of tracing and analysis presented in this information can be consolidated into one. In other cases, the detailed analysis might not be required at all.

Procedure

To investigate concurrency and locking and latching problems:

  1. Determine a period when the transaction is likely to encounter performance problems.
  2. When the period begins, start the GTF.
  3. Start the following traces, and specify the GTF as the destination:
    • Accounting Class(1, 2, 3, 7, 8).
    • Statistics Class(*)
    • Performance Class(1,2,3,6,7).
    You can specify the plan name, authorization ID, and package name associated with the problem transaction to reduce the volume of the trace information.
  4. Start the Db2 accounting classes 1, 2, and 3 to GTF to allow for the production of IBM OMEGAMON for Db2 Performance Expert on z/OS accounting reports.
  5. Stop GTF and the traces after a few minutes.
  6. Produce the following IBM OMEGAMON for Db2 Performance Expert on z/OS reports for analysis:
  7. Use the Db2 performance trace selectively for detailed problem analysis.
    End program-specific programming interface information.