PM63219: REPORT XES FALSE CONTENTIONS ACCURATELY IN DB2 ACCOUNTING AND STATS REPORTS

A fix is available

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • XES false contention on resource lock requests are not accounted
    for correctly in QTGSFLMG.
    These get included in XES heuristic async to async count as
    QTGSFLSE. IFCID0002 IFCID2
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All DB2 V10 data sharing users SYSPLEXDS.    *
    ****************************************************************
    * PROBLEM DESCRIPTION: 1. DB2 stats provided in IFCID 2        *
    *                        reports, in the field QTGSFLMG,       *
    *                        could be inaccurate.                  *
    *                      2. During DB2 restart, lock requests    *
    *                        may timeout prematurely if they wait  *
    *                        for retained locks (RETLWAIT is set). *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    1. DB2 statistical data for reporting false XES contentions in
    the field QTGSFLMG, are incorrectly summed together in the field
    QTGSFLSE. This field, QTGSFLSE, is the count of sync to async
    heuristic conversions for LOCK requests in XES.  As a result of
    this error, a monitoring tool may report inaccurate False
    Contention rate observed in DB2.
    
    2. During DB2 restart, a lock request in IRLM may get timeout
     before IRLMRWT threshold is reached where RETLWAIT is 1.
     As a result, the request waiting for held retain locks, may
    fail sooner with reason RESOURCE UNAVAILABLE waiting for held
    locks.
    

Problem conclusion

  • This APAR corrects the count of False XES Contentions recorded
    in the field QTGSFLMG of IFCID2 reports.
    
    This APAR also corrects DB2 Timeout logic for threads waiting
    for incompatible retained locks held in the system. DB2 threads
    will not timeout before the IRLMRWT interval when RETLWAIT is
    set.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM63219

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-04-24

  • Closed date

    2012-06-06

  • Last modified date

    2012-07-02

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

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

    UK79368

Modules/Macros

  •    DSNTLSUS DSNTLTIM
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RA10 PSY UK79368

       UP12/06/21 P F206

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


More support for:

DB2 for z/OS

Software version:

A10

Reference #:

PM63219

Modified date:

2012-07-02

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