A fix is available
APAR status
Closed as program error.
Error description
WMQ Client using shared conversation connect to the queue manager through the shared listener . 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 primary conversation (the primary conversation has rriSession.pSharedStatus set, but the other conversations do not). When the last conversation ends, rriFreeSess is invoked with rriWork.pSess containing the address of the conversation being ended. If this is not the primary conversation, i.e. the first conversation that started, then the shared status entry will not be deleted from DB2. . Additional symptoms: - You see high CPU and delayed response from DISPLAY CHSTATUS() SHORT This may be done from the command line or the CSQOREXX panel. Additionally, the channel status count is high, e.g. CSQN205I COUNT= 149862, RETURN=00000000, REASON=00000000 or the CSQOLCAA List Channels panel has a status of 149862 RUN - CSQX489E CSQXRESP Maximum instance limit 50 exceeded because the stop of the current channels is taking so long to complete (CSQXSTPC / CSQXSTOP / CSQXISTC / CSQMRM5F)
Local fix
To prevent orphaned status entries, do one of the following: - Do not connect WMQ clients through a shared listener as advised at http://publib.boulder.ibm.com/infocenter/wmqv7/v7r0/topic/com .ibm.mq.csqsat.doc/zc10560_.htm - Specify SHARECNV(0) in the SVRCONN channel definition See the "Performance implications of sharing conversations on client-connection channels" at http://publib.boulder.ibm.com/infocenter/wmqv7/v7r0/topic/com. ibm.mq.csqzaf.doc/mi12240_.htm - Obtain a ++APAR from the support center. . These work-arounds will not clean up entries that were already orphaned. There are a few clean-up options, but they could take a while like the DIS CHSTATUS did: . - 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: DELETE FROM CSQ.ADMIN_B_SCST WHERE CHLNAME='<channelname>' AND QSGNAME='<qsgname>'; where <channelname> and <qsgname> are replaced as appropriate for your system. . There may 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.
Problem summary
**************************************************************** * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 * * Release 0 Modification 1 and Version 7 * * Release 1 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: Orphaned shared channel status entries * * cause performance problems. * **************************************************************** * RECOMMENDATION: * **************************************************************** When issuing a DISPLAY CHSTATUS(*) SHORT command there is a delayed response and high CPU in that qmgr. Similar performance problems when trying to STOP a SVRCONN channel which connects to clients over a shared listener. This is caused by a large number of orphaned entries in the shared channel status table CSQ.ADMIN_B_SCST. These have been created when a WMQ client connects to a qmgr by a channel which is capable of running multiple conversations (SHARECNV > 1 in the SVRCONN definition) over a shared listener (defined with INDISP (GROUP)). When the last conversation ends the shared status entry should be deleted, but it is not deleted if the last conversation to end is not the first conversation to be started.
Problem conclusion
CSQXMMSA (CMQXRMSA at V710) has been updated to make sure the primary conversation points to the shared status entry. CSQXRCSI has been updated to use the primary conversation when deleting the shared status entry, if the pSharedStatus for the current session is null. 010Y 100Y CMQXRMSA CSQXRCSI CSQXRMSA
Temporary fix
Comments
APAR Information
APAR number
PM81116
Reported component name
WMQ Z/OS V7
Reported component ID
5655R3600
Reported release
010
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2013-01-22
Closed date
2013-02-26
Last modified date
2013-05-06
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK92011 UK92012
Modules/Macros
CMQXRMSA CSQXRCSI CSQXRMSA
Fix information
Fixed component name
WMQ Z/OS V7
Fixed component ID
5655R3600
Applicable component levels
Fix is available
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Document Information
Modified date:
06 May 2013