Interpreting trace status summary and trace messages

This topic shows examples of the Trace Status Summary panel and the Trace Messages panel. You can use this information to assess the progress and success of an activated or completed collect task.

About this task

If you have selected the Display task status option on the Collect Report Data panel, the Trace Status Summary panel is displayed. The following is an example: 
 06/22/13 10:16    Collect Report Data for Buffer Pool Analysis

                               Trace Status Summary
   Command ===> ______________________________________________________________

   _  Display messages

   Task description . . . . : Collect data for buffer pool activity
   Data set name  . . . . . : 'NKA.COLLECT.TRACE'
   Data set status  . . . . : Closed
   Record format  . . . . . : Standard
   Data type  . . . . . . . : Summary
   Start trace  . . . . . . : Immediately
   Trace type . . . . . . . : Continuously
   Task activated . . . . . : 06/22/13 11:41:14.46
   Task stopped . . . . . . : 06/22/13 11:41:18.80
   DB2 Trace data started . : 06/22/13 11:41:15.71
   Last collected . . . . . : 06/22/13 11:41:15.71
   Records read . . . . . . : 1580
   Buffer overflow  . . . . : 0
   Records lost . . . . . . : 0

    F1=Help     F2=Split    F3=Exit     F9=Swap      F12=Cancel

This panel shows details of the collect task, for example, when the task was started and stopped.

Procedure

  1. Assess this information carefully with regard to the intended usage. For example:
    • The Records read count should show a reasonable number of collected trace records.
    • The Buffer overflow count gives an indication whether you should configure a larger OP Buffer size for this collect task.
    • The Records lost count should be less than 2% of the total number of records read (especially if the collected data is used for simulation).

      During data collection, trace records can get lost if the CRD task cannot keep up with reading the records at the speed that DB2® writes them. For most of the Buffer Pool Analyzer functions, this is not a grave situation. The only function that is sensitive to trace record loss is simulation.

      If the loss rate is too high, ensure that the Performance Expert address spaces are dispatched with a priority equal or higher than the Db2 database services address space (DBM1).

  2. Select Display messages.
    The Trace Messages panel is displayed. The following is an example: 
     06/22/13 10:16    Collect Report Data for Buffer Pool Analysis

                               Trace Status Summary

                   IBM DB2 Buffer Pool Analyzer for z/OS   Row 1 to 18 of 19
   Command ===> ______________________________________________________________


                           Trace Messages
   FPEM0800I Task started at 06/22/13 11:40:41.915 for DB2 subsystem D721
   FPEM0819I Task description...Collect data for buffer pool activity
   FPEM0811I Task trigger...Immediate start
   FPEM0518E Nonzero IFI return code. RC 8, REASON X'00E60820'
   DSNW135I   -D721 P TRACE ALREADY ACTIVE, TRACE NUMBER 04
   DSN9023I   -D721 DSNWVCM1 '-START TRACE' ABNORMAL COMPLETION
   FPEM0818E An error occurred starting the DB2 traces above
   FPEM0801I Task stopped at 06/22/13 11:40:43.090
   FPEM0800I Task started at 06/22/13 11:41:14.464 for DB2 subsystem D721
   FPEM0819I Task description...Collect data for buffer pool activity
   FPEM0811I Task trigger...Immediate start
   DSNW130I   -D721 P TRACE STARTED, ASSIGNED TRACE NUMBER 04
   DSN9022I   -D721 DSNWVCM1 '-START TRACE' NORMAL COMPLETION
   FPEM0813I DB2 traces to OP1  started at 06/22/13 11:41:15.710
   DSNW131I   -D721 STOP TRACE SUCCESSFUL FOR TRACE NUMBER(S) 04
   DSN9022I   -D721 DSNWVCM1 '-STOP TRACE' NORMAL COMPLETION
   FPEM0814I DB2 traces to OP1  stopped at 06/22/13 11:41:15.713
   FPEM0815I 9 records written to 'NKA.COLLECT.TRACE'

    This panel shows messages about the progress and success of the collect task.

    In this example, the message FPEM0518E indicates that Db2 returned with a bad return code, RC 8, and with reason code REASON X'00E60820'. The Db2 trace command STOP TRACE (P) TNO (4) was issued, thereafter the collect task completed successfully.

    If you have requested that the collected data is to be compressed into a separate data set, and if errors occur during the compression, you also see messages preceded by message identifier TERSEMVS. These messages are from the TRSMAIN utility, which is used to perform the compression. For these errors, use the system code and the following information to diagnose the error.

    For more information, see IBM DB2 10 for z/OS®: Messages and Codes or IBM DB2 11 for z/OS: Messages and Codes.