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WebSphere MQ 7.0.1 and 7.1.0: Client channels using a shared listener and SHARECNV>1 may experience orphaned channel status entries, causing a build-up of rows in the CSQ.ADMIN_B_SCST table in DB2

Flash (Alert)


A WebSphere MQ (WMQ) Client using shared conversations connects to the queue manager through the shared listener (INDISP(GROUP)). An entry (row) is added into the shared channel status table CSQ.ADMIN_B_SCST. The shared status entry will be orphaned (not deleted) if the last conversation to end is not the first conversation started, when SHARECNV is greater than 1 on the SVRCONN definition.
The problem will be fixed by PM81116. The following details the steps required to avoid the problem and to cleanup the orphaned rows.


Reported symptoms have included:

  • Delayed responses when trying to do a STOP CHANNEL or DISPLAY CHSTATUS for a SVRCONN channel.
  • Displayed response when displaying the channels using the ISPF panels ('List Channels'), and the count of channels given in the Active column is higher than expected.
  • High CPU in the CHIN and MSTR address spaces.
  • A high count for the number of channel status in response to a DISPLAY CHSTATUS(..) SHORT command, e.g.
    CSQN205I COUNT= 149862, RETURN=00000000, REASON=00000000

    or the CSQOLCAA List Channels panel has a status with a high number such as
    149862 RUN
  • CSQX489E CSQXRESP Maximum instance limit 50 exceeded because the stop of the current channels is taking so long to complete

To prevent orphaned status entries, do one of the following:

Until the fix can be applied, circumventions include:

Clean up the orphaned status entries.

The work-arounds above will not clean up entries that were already orphaned. The options below will take a while depending on how many rows there are:

  • Restart the CHIN.
    Deletion of the orphaned entries will take place while the CHIN is terminating, so there may be a delay before it can be started again.
  • Run a SPUFI command:
    AND QSGNAME='<qsgname>';
    where <channelname> and <qsgname> are replaced as appropriate for your system.

    There might be contention for the table.

    You will get CSQX485E "Shared channel status error" and an FFST if a client ends after its entry has been deleted. These will not be a big impact, if there are not too many active clients at the time.
  • Delete and redefine the SVRCONN channel.
    This option will have more overhead than the SPUFI option due to the involvement of the MSTR and CHIN jobs in doing the clean-up.

Product Alias/Synonym


Document information

More support for: WebSphere MQ
Shared Channels

Software version: 7.0.1, 7.1

Operating system(s): z/OS

Reference #: 1625877

Modified date: 28 May 2013

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