PM62281: OMEGAMON DB2 Near Term History file management and initialization improvements

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Message KO2Z999E "OMPE V510 Service Error XSM=*UNKNOWN/ZSHIFT
  ABEND=S878 RSN=000E0000 MODE=ABEND"
  or Message KO2Z999E "OMPE V510 Service error SSM=OMPEXCF
  /OMPEXCF  ABEND=.S878 RSN=0000000C MODE=ABEND"
  
  
  
  Performance improvements:
  1. Ensure all NTH tasks are ready before accepting DB2
     instrumentation records reducing exposure to S878
     abends at NTH initialization
  2. Reduce below-the-line storage related to NTH VSAM
     file allocations for z/OS 1.12 users
  

Local fix

• The following options have provided relief until the PTF for
  this APAR can be applied
  
  - Edit the OMPE start-up member. This is the member by the same
    name as the started task in the RKD2PAR library.
    Move the command that opens the VTAM interface to the last
    command in the list - this commmand is of the form
    EXEC RVTMxxxxx
    Insert a line prior to EXEC RVTMxxxx that reads WAIT 30
    This will delay users ability to logon until all
    initialization is complete
  
  - Edit the OMPE00 member of RKD2PAR
    Add or change the following line
    XCFTASKS=4
    The default is 16 and may be changed to 4.  This would help
    reduce storage usage.
  
  - Reduce BUFSIZE from 4 meg to 2 meg.
    This is the size of the OPx buffers,   This is specified in
    the COPTxxxx members as BUFSIZE(2048).
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: OMEGAMON XE for DB2 PE/DB2PM                 *
  *                 users of component:                          *
  *                 -   OMEGAMON collector                       *
  ****************************************************************
  * PROBLEM DESCRIPTION: Abend S878 and high CPU observed        *
  *                      shortly after NTH started.              *
  *                                                              *
  ****************************************************************
  * RECOMMENDATION: Apply this PTF                               *
  *                                                              *
  ****************************************************************
  PROBLEM SUMMARY:
  1. A CPU hotspot is observed which does not appear to actually
  benefit the processing of NTH VSAM IO.
  2. SMF recording of DD-related statistics is an unnecessary
  overhead which may be eliminated during startup processing.
  3. Allocation-related control blocks occupy very limited
  below-the-line storage areas.
  4. Data recorded from the DB2 IFI traces may build up in
  storage if the output process is blocked or slowed in any way.
  5. Possible unlimited storage consumption causing abend S878.
  
  PROBLEM CONCLUSION:
  1. Remove the CPU hotspot.
  2. For zOS V1.12 and above, specify an allocation parameter
  which will eliminate DD-related SMF accounting for the NTH VSAM
  files.
  3. Specify allocation parameters which will cause
  allocation-related control blocks to be placed in 31-bit
  storage.
  4. Wait until the output process is fully initialized before
  issuing the DB2 -START TRACE commands.  This will help to
  prevent the build up of data waiting to be output to the VSAM
  linear datasets.
  5. Place a hard limit on storage occupied by the data waiting
  to be written to the VSAM files.
  

Problem conclusion

• 1. Remove the CPU hotspot.
  2. For zOS V1.12 and above, specify an allocation parameter
  which will eliminate DD-related SMF accounting for the NTH VSAM
  files.
  3. Specify allocation parameters which will cause
  allocation-related control blocks to be placed in 31-bit
  storage.
  4. Wait until the output process is fully initialized before
  issuing the DB2 -START TRACE commands.  This will help to
  prevent the build up of data waiting to be output to the VSAM
  linear datasets.
  5. Place a hard limit on storage occupied by the data waiting
  to be written to the VSAM files.
  
  KEYWORDS : DB2 -START TRACE CPU NTH IFI VSAM
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UK79043 PM68880

Modules/Macros

• KO2HDTPB KO2HINTB KO2HSQIB KO2PLIOF KO2PUTLF
  

Fix information

• Fixed component name

  OM XE DB2PE/PM

• Fixed component ID

  5655OPE00

Applicable component levels

• R510 PSY UK79043

     UP12/05/26 P F205

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.