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PM67558: High DBM1 pre-emptible SRB CPU for RTS system thread in DSNGERTS

A fix is available

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APAR status

  • Closed as unreproducible in next release.

Error description

  • High DBM1 pre-emptible SRB CPU usage can be observed in DB2 V10
    (any mode), triggered by RTSTST service task (RTS) having to
    process a huge number of control blocks that represent
    information when a package was last used. A dump shows high
    CPU usage in module DSNGERTS.
    

Local fix

  • Set ZPARM DISABLE_EDMRTS=YES and recycle DB2
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: DB2 user of real time statistics for         *
    *                 last used information to SYSPACKAGE          *
    ****************************************************************
    * PROBLEM DESCRIPTION: Customer may hit high CPU usage from    *
    *                      real time statistics (RTS)              *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    DB2 maintains a list of real time statistic (RTS)
    control blocks to keep track of package execution. The RTS
    service task periodically externalizes the last used
    information to the SYSPACKAGE table. If the table SYSPACKAGE
    is accessed by another job concurrently, updating the last used
    information may not be successful, as a result, the RTS control
    blocks can accumulate, which could cause high CPU usage.
    

Problem conclusion

Temporary fix

Comments

  • DB2 has been changed to purge RTS control blocks if the total
    number reach the threshold.
    

APAR Information

  • APAR number

    PM67558

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    A10

  • Status

    CLOSED UR1

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-06-25

  • Closed date

    2012-08-03

  • Last modified date

    2012-09-05

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

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

    UK80828

Modules/Macros

  • DSNGERTS
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RA10 PSY UK80828

       UP12/08/21 P F208

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.

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Document Information

Modified date:
05 September 2012