Collecting data for general performance problems

For performance problems that are not related to access path issues, collect a description of the problem symptoms, SMF data, RMF data, and a supervisor call (SVC) dump.

To collect diagnostic data for general performance problems:

1. Write a description of the problem and include answers to these questions:
   1. What are the names of packages, user IDs, and subsystems that are experiencing performance problems?
   2. If a job abended, what were the abend codes?
   3. Has anything recently changed in the environment that caused the problem?
   4. How do you reproduce the problem?
2. Collect SMF type 100-102 trace records by issuing Db2 START TRACE commands for both a successful and an unsuccessful run.
   For example, start both accounting and statistics traces:

   

   -START TRACE(ACCTG) CLASS(1,2,3,7,8) DEST(SMF)
   -START TRACE(STAT) CLASS(1,3,4,5,6)  DEST(SMF) 

   

   Separate accounting data from other transactions to prevent accumulation. In a Resource Recovery Services (RRS) or distributed data facility (DDF) attach environment, set the ACCUMACC subsystem parameter to NO.

3. Collect RMF Monitor I and RMF Monitor II SMF type 70-79 trace records by issuing RMF commands for both a successful and unsuccessful run:
   1. Start RMF Monitor I:

      MODIFY RMF, START ZZ
      

   2. Start RMF Monitor II:

      MODIFY RMF, START session-id

      In this example, session-id is two alphanumeric characters (not ZZ) to start RMF Monitor II.
4. Issue the z/OS DUMP command to dump Db2 associated address spaces:

     DUMP COMM=(title),
     JOBNAME=(ssnmIRLM,ssnmMSTR,ssnmDBM1,ssnmDIST),
     SDATA=(RGN,CSA,SQA,LPA,LSQA,SWA,PSA,ALLNUC,XESDATA,TRT,GRSQ,SUM),END
   

   where title is the title of the dump data set and ssnm is the Db2 subsystem name.
5. If IBM® Support asks you to do so, issue this command:

   

   DISPLAY DATABASE(database-name) SPACENAM(space-name) PART(part-num) LRSN

   

   This command is used for diagnosis of performance problems that are related to over-locking or inefficient space reuse.

   
6. Collect service SQL documentation that describes the environment for the SQL statement, as described in Collecting service SQL documentation.