A fix is available
APAR status
Closed as program error.
Error description
You have XA clients which call xa_open and xa_close in a loop, incrementing their rmid each time. When these clients are running against an MQ server, you see amqrmppa using 100% CPU and an increasing amount of RAM. A closer look at the trace shows that we are actually being held up by the processing being done in zswSaveRmid
Local fix
n/a
Problem summary
**************************************************************** USERS AFFECTED: Users of XA may be affected by this problem Platforms affected: MultiPlatform **************************************************************** PROBLEM DESCRIPTION: A function iterates over a linked list of structures, one of which is created for each different rmid that we encounter. Every time that the TM calls xa_open(), it is passing in a new rmid. This is potentially causing the queue manager to have to iterate over a very long linked list of structures, and it is this which is causing the high CPU usage.
Problem conclusion
The change will cause MQ to release any memory allocated on an xa_open(), when xa_close() is called. Since the change prevents the internal linked list from getting too big, the time spent iterating this list should be reduced. --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: Version Maintenance Level v7.1 7.1.0.9 v7.5 7.5.0.5 v8.0 8.0.0.2 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
IT03414
Reported component name
WMQ BASE MULTIP
Reported component ID
5724H7241
Reported release
750
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2014-07-30
Closed date
2014-10-21
Last modified date
2017-11-21
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
WMQ BASE MULTIP
Fixed component ID
5724H7241
Applicable component levels
R750 PSY
UP
[{"Line of Business":{"code":"LOB45","label":"Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSFKSJ","label":"WebSphere MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"7.5"}]
Document Information
Modified date:
25 September 2021