IBM Support

IT28091: Application intermittently receives MQRC_HOST_NOT_AVAILABLE error while connecting to the queue manager.

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APAR status

  • Closed as program error.

Error description

  • Attempts by an application to connect to a queue manager using
    a server connection SVRCONN channel with SHARECNV > 1
    specified, unexpectedly receives
    MQRC 2538 MQRC_HOST_NOT_AVAILABLE.
    .
    Application has several threads with working connections to the
    queue manager. Client connections in the application work fine
    for some time, then start to fail.
    

Local fix

  • Set SHARECNV(1) on the SVRCONN channel definition
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    All MQ client application users who use SVRCONN channels with
    SHARECNV value greater than 1.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    When shared conversation(SHARECNV) is set to any value greater
    than 1 then it means multiple logical connections
    (conversations) use the same channel instance. The channel
    instance is closed if all the conversations sharing the channel
    are disconnected.  A small timing window allowed a new
    conversation to pick the same channel instance  that was being
    ended by another thread and this results in the
    MQRC_HOST_NOT_AVAILABLE error.
    

Problem conclusion

  • The code has been modified to ensure that a new conversation
    request does not pick a channel instance that is being
    terminated.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.8
    v9.0 CD    9.1.0.0
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT28091

  • Reported component name

    IBM MQ BASE M/P

  • Reported component ID

    5724H7261

  • Reported release

    900

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2019-02-13

  • Closed date

    2019-08-19

  • Last modified date

    2020-03-16

  • 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

    IBM MQ BASE M/P

  • Fixed component ID

    5724H7261

Applicable component levels

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.0","Edition":"","Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
16 March 2020