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IC83661: APPLICATION ISSUING XA CONNECTIONS TO DB2/Z MAY RECEIVE -913 ERRORS OR MAY HANG

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Some TM eg MQ uses dual transport model.  In this model, a
    transaction, over transport A, is tied to a member from xa_start
    to xa_end, but xa_prepare(readonly), xa_prepare plus xa_commit
    or xa_rollback, or xa_rollback comes in over transport B,
    possibly from another application process.  If the end server is
    zOS, Syncpoint manger (DB2 connect server) with connection
    concentrator is required to support XA applications. Becuase of
    the APAR,  requests to end the transaction by
    TM(xa_prepare,xa_commit,xa_rollback) was not forwarded to the
    zDB2, and  resrouces locked by the transaction were not released
    on server, eventhough TM completed the transaction. When
    application tried to run other transaction, resultsed SQLCODE
    913 (deadlock, locktimeout)
    
    The problem can only happen with DB2 Version 9.7 Fix Pack 5
    client.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All users utilizing XA connections against DB2/z using DB2   *
    * Version 9.7 Fix Pack 5 client.                               *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * Because of the defect, DB2 Connection concentrator did not   *
    * switched out the connection at the end of transaction ie on  *
    * xa_commit/xa_rollback. The same connection was used to       *
    * receive new set to XA request instead of picking the agent   *
    * associated with XID. As wrong agent was used to process the  *
    * XID, it resulted NOTA  on DB2 connect server (SYNCPOINT      *
    * manager). The request was not forwarded to the end server    *
    * (zOS) and transaction remain incomplete on zOS. When another *
    * transaction (with different XID) tried to use the same       *
    * resources resulted with lock-timeout. .                      *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Upgrade to DB2 Version 9.7 Fix Pack 6.                       *
    ****************************************************************
    

Problem conclusion

  • The problem is first fixed in DB2 Version 9.7 Fix Pack 6 and all
    subsequent Fix Packs.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC83661

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-05-22

  • Closed date

    2012-06-07

  • Last modified date

    2012-06-07

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

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

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP

  • R980 PSN

       UP

  • RA10 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC83661

Modified date: 07 June 2012