IBM Support

IC82293: SUBAGENT TRAPS OR HANGS AFTER DETECTING WLM THRESHOLD VIOLATION

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • Subagent may trap or hang after detecting WLM threshold
    violation while it is in FCM wait.  In the trap case, a subagent
    may trap in function ReceiveBuffer (callstack 1 below).  In the
    hang case, the application will become unresponsive and cannot
    be forced off.  The subagent will remain stuck waiting on a
    waitpost in function WaitSendReady (callstack 2 below) or
    WaitRecvReady (callstack 3 below).  Check to see if the database
    has a reactive threshold that applies to the trap/hung
    application's current activity.  If so, check the event monitor
    table to see if the activity has violated the threshold.  This
    trap/hang is only possible on V9.7 FP5 on DPF instances with
    reactive WLM thresholds enabled.
    
    Callstack 1 - Trap case:
    
    sqkfChannel::ReceiveBuffer
    sqkdBdsBufferTable::getNextBuffer
    sqlkd_rcv_buffer
    sqlkd_rcv_get_next_buffer
    sqlkd_rcv_data
    sqlkdReceiveReply
    sqleInformCoordRequest
    sqleRemoteLobBuffer
    ...
    sqlrr_subagent_router
    sqleSubRequestRouter
    sqleProcessSubRequest
    sqeAgent::RunEDU
    
    Callstack 2 - Hang case (WaitSendReady):
    
    sqloWaitEDUWaitPost
    sqkfChannel::WaitSendReady
    sqkfChannel::SendDataBuffer
    sqlkqsnd
    sqlktsnd
    sqlkt_pack_tuple
    sqlktins
    sqlritqb
    sqlriSectInvoke
    sqlrr_dss_router
    sqlrr_subagent_router
    sqleSubRequestRouter
    sqleProcessSubRequest
    sqeAgent::RunEDU
    
    Callstack 3 - Hang case (WaitRecvReady):
    
    sqloWaitEDUWaitPost
    WaitRecvReady
    ReceiveBuffer
    sqlkqrcv
    sqlktrcv
    sqlkt_unpack_tuple
    sqlktftc
    sqlritqa
    sqlriSectInvoke
    sqlrr_dss_router
    sqlrr_subagent_router
    sqleSubRequestRouter
    sqleProcessSubRequest
    sqeAgent::RunEDU
    

Local fix

  • The workaround is to kill and restart the instance, and disable
    reactive WLM thresholds.  The permanent fix is to apply V9.7 FP6
    or above.
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * DPF with reactive WLM thresholds                             *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * See Error Description                                        *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Customers on V9.7 FP5 should upgrade to V9.7 FP6 or above.   *
    ****************************************************************
    

Problem conclusion

  • This problem only exists in V9.7 FP5.  A fix for this issue is
    delivered to V9.7 FP6.  The hang should no longer be possible
    after fix is applied.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC82293

  • 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

    2012-03-27

  • Closed date

    2012-06-04

  • Last modified date

    2012-06-04

  • 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

[{"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSEPGG","label":"DB2 for Linux, UNIX and Windows"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.7","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Document Information

Modified date:
04 June 2012