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PI13499: GENERIC SERVER CLUSTER RETRY BEHAVIOR CAN RESULT IN INCORRECT APPLICATION ROUTING.

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APAR status

  • Closed as program error.

Error description

  • ODR may route requests to the wrong GSC when RulesOverAffinity
    is set. Lets's assume that there are two GSCs running
    different applications in an ODR cell: GSC1 has members
    hosting application A(with context root /A) and GSC2 has
    members hosting application B with context root(/A/B). Let's
    also assume that the ODR routing rules are configured
    appropriately. The sequence of events demonstrating the
    problem is given below:
    
    A request, /A/B/Ping, is made to application B(which is sent
    to GSC2). Application B responds with its affinity cookie
    JSESSIONIDB.
    A different request, /A/Ping, is made targetting application
    A. If a member of GSC1 is down and this request were to go to
    that as part of the load balancing algorithm, then a retry is
    triggered to select a different server.
    However, during the retry the request is sent to GSC2 member
    instead of another GSC1 member because of the affinity cookie,
    JSESSIONDB.
    

Local fix

  • N/A
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of WVE 7.0.0.4 and lower          *
    *                  versions are affected by this behaviour.    *
    ****************************************************************
    * PROBLEM DESCRIPTION: As mentioned in the error               *
    *                      description, a wrong server is chosen   *
    *                      during retry. This will result in an    *
    *                      incorrect routing behaviour.            *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    This problem was due to improper handling of
    RulesOverAffinity for the request during a retry attempt to
    select another member in the same cluster.
    

Problem conclusion

  • Changes have been made to handle RulesOverAffinity properly
    during retry attempt. This issue will be resolved in the next
    available fix pack for WebSphere Virtual Enterprise V.7.0.0.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PI13499

  • Reported component name

    WAS VIRTUAL ENT

  • Reported component ID

    5725C9203

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2014-03-11

  • Closed date

    2014-06-17

  • Last modified date

    2014-06-17

  • 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

    WAS VIRTUAL ENT

  • Fixed component ID

    5725C9203

Applicable component levels

  • R700 PSY

       UP

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Document Information

Modified date:
27 April 2022