PM73905: DEADLOCK BETWEEN RTS AND A MASS DELETE APPLICATION

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

  • RTS was updating sysibm.sysindexspacestats .
    At the same time, within the same commit scope, an application
    was doing a MASS DELETE and updating sysindexspacestats also.
    The RTS thread was updating sysindexspacestats in ASCENDING
    order.
    The mass delete application was updating sysindexspacestats in
    DESCENDING order.
    This lead to a deadlock.
    eg
    DSNT375I  -DSN  PLAN=(mass delete application plan)
              ...
              IS DEADLOCKED WITH PLAN=         WITH
              CORRELATION-ID=014.RTSTST00
    .
    DSNT501I  -DSN  DSNILMCL RESOURCE UNAVAILABLE
              ...
              REASON 00C90088
              TYPE 00000304
              NAME DSNDB06 .SYSRTSTS.X'00011C' '.X'0D'
    Looking at the LKTR:
     The RTS thread (Corrid: 014.RTSTST00) is updating dbid(0006)
     obid(0366) sysibm.sysindexspacestats rows, in ASCENDING order.
     Last few rows for example:
    page x'00011C' id x'0B' S ->U ->X
    page x'00011C' id x'0C' S ->U ->X
    page x'00011C' id x'0D' S ->U ->X
    page x'00011C' id x'0E' Fails to get S lock, fails to get U lock
    .
     The thread doing mass delete is also updating dbid(0006)
     obid(0366) sysibm.sysindexspacestats rows, in DESCENDING order.
     Last few rows for example:
    page x'00011C' id x'0F' S ->U ->X
    page x'00011C' id x'0E' S ->U ->X (so RTS thread can't have it)
    page x'00011C' id x'0D' Fails to get S lock, fails to get U
                            lock. (RTS thread has X lock).
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: DB2 9 for z/OS, DB2 10 for z/OS, and         *
    *                 DB2 11 for z/OS users who may run a mass     *
    *                 delete operation.                            *
    ****************************************************************
    * PROBLEM DESCRIPTION: Deadlock between RTS daemon and an      *
    *                      application doing a mass delete may     *
    *                      occur when the application accesses     *
    *                      SYSTABLESPACESTATS or                   *
    *                      SYSINDEXSPACESTATS table in descending  *
    *                      OBID order.                             *
    ****************************************************************
    * RECOMMENDATION: Apply corrective PTF when available          *
    ****************************************************************
    A deadlock between RTS daemon and an application doing a mass
    delete operation occurs when the application is accessing
    SYSIBM.SYSTABLESPACESTATS or SYSIBM.SYSINDEXSPACESTATS
    table in descending OBID order while the
    RTS daemon accesses the tables in ascending order.
    

Problem conclusion

  • DB2 is updated to avoid deadlock situations between RTS daemon
    and applications with mass delete operations.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM73905

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-09-28

  • Closed date

    2013-10-26

  • Last modified date

    2013-12-02

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

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

    UI12034 UI12036 UI12037

Modules/Macros

  • DSNICMT2 DSNIRTSU DSNIRTSX
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RA10 PSY UI12034

       UP13/11/15 P F311

  • RB10 PSY UI12036

       UP13/11/15 P F311

  • R910 PSY UI12037

       UP13/11/15 P F311

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:

910

Reference #:

PM73905

Modified date:

2013-12-02

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