A fix is available
APAR status
Closed as program error.
Error description
Old title: "AFTER MIGRATION TO MQ 9.2, MQPUT1 RESPONSE TIMES MAY TAKE 10 SECONDS TO COMPLETE" . After migration to MQ 9.2 an application experiences a response time of 10 seconds for PUT calls. Time gap symptoms can be seen for example in CICS AUX trace such as this entry > AP abcd MQTRU ENTRY - APPLICATION-REQUEST - MQPUT1 -> TIME- <> AP abcd MQTRU EXIT - APPLICATION-REQUEST - MQPUT1. Development finds this occurs due to an error remaking a cluster subscription for a 'stale' QMGR object. Cluster objects can go stale if they've not been used for a long time. A code defect causes this subscription to be made for the wrong object. The MQOPEN processing subsequently waits for a maximum of 10 seconds to see if the subscription has been created properly, but due to the subscription having been made for the wrong object, it will always end up waiting the full 10 seconds. . ** PH38014 fixes a similar 10-second delay on a full repository. . Additional symptoms and keywords: If the puts to cluster queues are being done by channels, messages might build up on remote transmission queues (xmitq). If enough incoming channels are affected, that can cause contention for adapter or dispatcher TCBs in the CHIN job. There might also be contention for latches in the BUFFPOOL. These points of contention can affect other processing, including outgoing channels. . A receiver (RCVR) channel putting to a cluster queue might receive error: CSQX208E CSQXRESP Error receiving data, channel <channel-name> connection <connection-name> (queue manager <queue-manager-name>) TRPTYPE=TCP RC=00000480 reason=00000000 . Another symptom was that messages built up on SYSTEM.QSG.TRANSMIT.QUEUE when IGQ(ENABLED) was used. The messages were targeted for cluster queues, and the IGQ thread (IGQAGN00) had 10-second delays in CSQMZLOO during MQPUT processing.
Local fix
ALTER CHANNEL for the cluster receiver channels will allow the subscription to be made correctly, even if the ALTER is only done to the DESCR field. . Before the PTF is applied, it is best to do this command at least every 5 days as one path of this problem can allow the problem to happen again after 6 days.
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 2 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: If a cluster object hasn't been used * * for more than 30 days, then attempts to * * open it on partial repositories may * * result in 10 second delays. Depending * * on the type of the cluster object, the * * delays may persist for later MQOPEN * * calls. * **************************************************************** Partial cluster repositories use subscriptions to keep track of cluster objects. The full repositories publish new definitions for the objects when required. If an object hasn't been used for over 30 days, then attempts to open the object may result in the cluster subscriptions being remade. A defect in the code causes these cluster subscriptions to be remade incorrectly. The open processing then waits for the subscription to complete, but since the subscription was remade incorrectly, it results in a 10 second wait.
Problem conclusion
The code has been changed to correctly remake cluster subscriptions for cluster objects.
Temporary fix
Comments
APAR Information
APAR number
PH34589
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
200
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2021-02-17
Closed date
2021-06-30
Last modified date
2022-12-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI74363
Modules/Macros
CSQMZLOO CSQXRRMF
Fix information
Fixed component name
IBM MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
R200 PSY UI74363
UP21/04/01 P F103
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
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Document Information
Modified date:
02 December 2022