IC94869: COORDINATOR AGENT MAY HANG WITH PENDING REMOTE REQUEST STATUS DUE TO DISCARDED BUFFER.

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • The FCM buffer discarded message can be seen in db2diag.log on a
    remote partition.
    
    2013-08-05-01.09.07.477149+480 I16501733A701      LEVEL: Error
    PID     : 2294174              TID  : 1543        PROC : db2sysc
    10
    INSTANCE: db2inst1             NODE : 010
    EDUID   : 1543                 EDUNAME: db2fcmr 10
    FUNCTION: DB2 UDB, fast comm manager,
    sqkfFastCommManager::RouteInboundBuffer, probe:30
    DATA #1 : <preformatted>
    rc = 0x0; buffer addr: 7800000a3a39080
    buffer info: channel ID=478015836, sender node=0, conduit ID=0,
    sequenceNo=4294967295, sessionId=0, priority=0,
    msgFlags=0x30009,
    msgType=1
    app_hdl=0-18506, app_stamp=594176, sourceNode=0, idtype=1,
    idflags=0, bdsCounter=28, nestedCounter=0
    (BDS) subtaskId=33, sendNode=0, intFlags=0x0, bdsFlags=0x2
    (BQS) counter=33, node=0
    
    DB2 has an internal unique counter called app_stamp based off
    epoch time for each incarnation of an app-handle. But due to the
    way DB2 calculates this unique number, it can wrap. Because the
    unique identifier wraps, it caused a problem in the logic of
    our code that ultimately lead to a buffer being discarded, and
    an application being hung.
    
    Note :
    - On DB2 Version 9.7 or higher, EDUNAME is db2pdbc and the
    FUNCTION is sqkfFastCommManager::DeliverBufferToTargetChannel,
    probe:30
    - This issue only applies to the DB2&#65449; partitioned database
    environment.
    - This issue also impacts pureScale instance.
    

Local fix

  • Recycle the db2 instance.
    

Problem summary

  • The FCM buffer discarded message can be seen in db2diag.log on a
    remote partition.
    
    2013-08-05-01.09.07.477149+480 I16501733A701      LEVEL: Error
    PID     : 2294174              TID  : 1543        PROC : db2sysc
    10
    INSTANCE: db2inst1             NODE : 010
    EDUID   : 1543                 EDUNAME: db2fcmr 10
    FUNCTION: DB2 UDB, fast comm manager,
    sqkfFastCommManager::RouteInboundBuffer, probe:30
    DATA #1 : <preformatted>
    rc = 0x0; buffer addr: 7800000a3a39080
    buffer info: channel ID=478015836, sender node=0, conduit ID=0,
    sequenceNo=4294967295, sessionId=0, priority=0,
    msgFlags=0x30009,
    msgType=1
    app_hdl=0-18506, app_stamp=594176, sourceNode=0, idtype=1,
    idflags=0, bdsCounter=28, nestedCounter=0
    (BDS) subtaskId=33, sendNode=0, intFlags=0x0, bdsFlags=0x2
    (BQS) counter=33, node=0
    
    DB2 has an internal unique counter called app_stamp based off
    epoch time for each incarnation of an app-handle. But due to the
    way DB2 calculates this unique number, it can wrap. Because the
    unique identifier wraps, it caused a problem in the logic of
    our code that ultimately lead to a buffer being discarded, and
    an application being hung.
    
    Note :
    - On DB2 Version 9.7 or higher, EDUNAME is db2pdbc and the
    FUNCTION is sqkfFastCommManager::DeliverBufferToTargetChannel,
    probe:30
    
    - This issue only applies to the DB2&#169; partitioned database
    environment.
    - This issue also impacts pureScale instance.
    

Problem conclusion

  • First fixed in DB2 Version 10.5 Fix Pack 3.
    

Temporary fix

  • Recycle the db2 instance.
    

Comments

APAR Information

  • APAR number

    IC94869

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    A50

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-08-13

  • Closed date

    2014-05-06

  • Last modified date

    2014-05-06

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

    IC94832

  • 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

  • RA50 PSY

       UP



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Document information


More support for:

DB2 for Linux, UNIX and Windows

Software version:

10.5

Reference #:

IC94869

Modified date:

2014-05-06

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