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PI53085: A MESSAGE FLOW CONTROL MECHANISM IN ME-TO-ME COMMUNICATIONS IN PUB/SUB ENVIRONMENTS TO PREVENT MESSAGE PILE UPS IN THE TARGET ME

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APAR status

  • Closed as program error.

Error description

  • In the ME-to-ME communication in complex Publish/Subscribe
    topologies, if the target messaging engine (ME) is running
    slow, then there might be a situation where large number of
    messages can pile up in the target ME waiting to be processed.
    This happens because the source ME sends off the messages as
    they are produced to the target ME without worrying about its
    current health condition. This APAR introduces message
    flow control that adjusts itself according to the current
    health state of the target ME. The source ME sends a certain
    number of messages to the target ME and checks whether it
    received sufficient acknowledgements for the messages it has
    sent so far. If sufficient acknowledgements are already
    received then it continues to send the messages. Otherwise it
    waits for these acknowledgements to arrive before sending the
    next batch of messages.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application      *
    *                  Server                                      *
    ****************************************************************
    * PROBLEM DESCRIPTION: In publish/subscribe topologies, when   *
    *                      messages flow across messaging          *
    *                      engines (MEs), the health of the        *
    *                      target ME needs to be considered for    *
    *                      flow control.                           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    When the target MEs receiving the messages becomes slow for
    any reason, the source ME can evaluate the situation by
    investigating the acknowledgements received for the messages
    already sent. These acknowledgements help to control the
    message flow. This can prevent further congestion of the
    target ME which has already become unhealthy.
    

Problem conclusion

Temporary fix

Comments

APAR Information

  • APAR number

    PI53085

  • Reported component name

    WEBS APP SERV N

  • Reported component ID

    5724H8800

  • Reported release

    850

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2015-11-26

  • Closed date

    2016-03-08

  • Last modified date

    2016-03-08

  • 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

    WEBS APP SERV N

  • Fixed component ID

    5724H8800

Applicable component levels

  • R800 PSY

       UP

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Document Information

Modified date:
28 April 2022