A fix is available
APAR status
Closed as new function.
Error description
ALLOW ECSA storage used by threads to be limited. * Additional information: Regarding messages added by this APAR: CSQ3202E may be seen for batch applications (including RRS applications, e.g. DB2 stored procedures and WAS)), whereas CSQM078E may be seen for CICS and the CHIN, and as well as for RRS applications. . SMF 115 subtype 5 records produced by statistics CLASS(3) trace can be be used to monitor the size of the 'ACE/PEB' storage pool, and hence set an appropriate value for ACELIM. The total amount of ECSA storage used by the queue-manager can be obtained from SMF 115 subtype 7 records written by statistics CLASS(2) trace (the first two elements in QSRSPHBT added together).
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 * * Release 1 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: WebSphere MQ does not provide a * * suitable mechanism to set a hard limit * * on the amount of ECSA used for control * * blocks that are allocated for * * application connections. * **************************************************************** * RECOMMENDATION: * **************************************************************** Each application that connects to WebSphere MQ requires a small amount of ECSA storage to contain various thread-related control blocks pertaining to that connection. In addition, DB2 stored procedures using RRS and MQ may generate a very large number of these connections. In extreme cases, the high usage of ECSA by these connections may be enough to exhaust all of the free ECSA storage in an LPAR which can result in an LPAR outage. The PTF for this APAR introduces a new ACELIM Queue Manager property that can set a hard limit on the amount of storage allocated to thread-related control blocks. While this will not prevent problems from occurring in WebSphere MQ if the usable pool of ECSA storage is depleted, it does allow an administrator to ensure that such an event will not lead to an LPAR-wide EXSA shortage.
Problem conclusion
Temporary fix
Comments
A new Queue Manager property, ACELIM has been added. The following changes to the WebSphere MQ Knowledge Center will be made: WebSphere MQ 7.1.0 > WebSphere MQ > Reference > Administration reference > MQSC reference > The MQSC commands > SET SYSTEM The "Parameter Block" section will be updated with the following entry: ACELIM Size of ACE storage pool in 1 KB blocks. ---------------------------------------------------------------- WebSphere MQ 7.1.0 > WebSphere MQ > Configuring > Configuring z/OS > Customizing your queue managers > Task 17: Tailor your system parameter module > Using CSQ6SYSP Table 1. Default values of CSQ6SYSP parameters will be updated as follows: Parameter: ACELIM Description: Size of ACE storage pool in 1 KB blocks. Default value: 0 (no limit). SET command: X ACELIM Specifies the maximum size of the ACE storage pool in 1 KB blocks. The number must be in the range 0-999999. The default value of zero means no imposed constraint, beyond what is available in the system. You should only set a value for ACELIM on queue managers that have been identified as using exorbitant quantities of ECSA storage. Limiting the ACE storage pool has the effect of limiting the number of connections in the system, and so, the amount of ECSA storage used by a queue manager. Once the queue manager reaches the limit it is not possible for applications to obtain new connections. The lack of new connections causes failures in MQCONN processing, and applications coordinated through RRS are likely to experience failures in any WebSphere MQ API. Note that, you should consider setting ACELIM as a mechanism to protect a z/OS image from a badly behaving queue manager, rather than as a means to control application connections to a queue manager. ---------------------------------------------------------------- WebSphere MQ 7.1.0 > WebSphere MQ > Planning > Planning your WebSphere MQ environment on z/OS > Planning your storage and performance requirements > Address space storage The section on "Common Storage" will be updated as follows: You can set a limit to the common storage, used by logical connections to the queue manager, with the ACELIM configuration parameter. The ACELIM control is primarily of interest to sites where DB2 stored procedures cause operations on WebSphere MQ queues. When driven from a stored procedure, each WebSphere MQ operation can result in a new logical connection to the queue manage. Large DB2 units of work, for example due to table load, can result in an excessive demand for common storage. ACELIM is intended to limit common storage use and to protect the z/OS system. Using ACELIM causes WebSphere MQ failures when the limit is exceeded. ---------------------------------------------------------------- WebSphere MQ 7.1.0 > WebSphere MQ > Reference > Messages > Messages and reason codes for z/OS > Messages for WebSphere MQ for z/OS > Initialization procedure and general services messages (CSQY...) > CSQY101I, CSQY102I, CSQY103I, CSQY104I, CSQY105I, CSQY106I, CSQY107I, CSQY108I, CSQY109I, CSQY130I: csect-name parms Message CSQY134I is added to the list of messages that are listed as follows: CSQY101I, CSQY102I, CSQY103I, CSQY104I, CSQY105I, CSQY106I, CSQY106I, CSQY107I, CSQY108I, CSQY109I, CSQY130I, CSQY134I: csect-name parms ---------------------------------------------------------------- The following messages have been added to WebSphere MQ: CSQ3202E CONNECTION FOR jobname FAILED, INSUFFICIENT ECSA STORAGE TO CREATE ACE Explanation jobname attempted to connect to WebSphere MQ using the MQCONN, or MQCONNX, API call. There was insufficient common storage available to build the control blocks to represent the connection and the connection attempt failed. There might be a system wide ECSA shortage, or the storage available for creating new queue manager connections might be limited by the ACELIM system parameter. System action The MQCONN or MQCONNX API call, used by jobname returns MQCC_FAILED, together with reason code MQRC_Q_MGR_NOT_AVAILABLE 2059 Queue manager processing continues. CSQY228E ACE pool cannot be extended, ACELIM reached Explanation The internal storage pool used to manage control blocks representing new connections to the queue manager has reached the limit defined by the ACELIM system parameter. System action Queue manager processing continues. New connection requests might have failed, message CSQ3202E or CSQM078E give further information about the affected jobs. CSQM078E csect-name Unable to create thread structures for connection-type connection from jobname, insufficient ACE storage Severity 8 Explanation jobname attempted to create a new connection to WebSphere MQ as the result of issuing the first WebSphere MQ API call on a new thread. The connection-type is likely to be RRSBATCH. There was insufficient common storage available to build the control blocks to represent the connection and the connect attempt failed. There might be a system wide ECSA shortage, or the storage available for creating new queue manager connections might be limited by the ACELIM system parameter. System action WebSphere MQQ API request fails with return code MQRC_STORAGE_NOT_AVAILABLE 2071. Queue manager processing continues ×**** PE15/05/14 FIX IN ERROR. SEE APAR PI21198 FOR DESCRIPTION ×**** PE15/07/10 FIX IN ERROR. SEE APAR PI44704 FOR DESCRIPTION ×**** PE15/08/12 FIX IN ERROR. SEE APAR PI46796 FOR DESCRIPTION
APAR Information
APAR number
PI07502
Reported component name
WMQ Z/OS V7
Reported component ID
5655R3600
Reported release
100
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2013-12-05
Closed date
2014-07-22
Last modified date
2016-04-12
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI19842 UI19843 UI19844 UI19845 UI19846 UI19847
Modules/Macros
CMQCFA CMQCFC CMQCFP CSQFMDIC CSQFMDIE CSQFMDIF CSQFMDIK CSQFMDIU CSQFMTXC CSQFMTXE CSQFMTXF CSQFMTXK CSQFMTXU CSQFSTXC CSQFSTXE CSQFSTXF CSQFSTXK CSQFSTXU CSQFXTXC CSQFXTXE CSQFXTXF CSQFXTXK CSQFXTXU CSQFYDIC CSQFYDIE CSQFYDIF CSQFYDIK CSQFYDIU CSQF3DIC CSQF3DIE CSQF3DIF CSQF3DIK CSQF3DIU CSQJC00A CSQJC00B CSQJC00D CSQJC009 CSQMCNTH CSQMCPRH CSQSFBK CSQYSCMD CSQZINIT CSQ3AMI2 CSQ3CT30 CSQ3ID50 CSQ3SSES CSQ3SSI2 CSQ6SYSP CSQ9SCNA
Fix information
Fixed component name
WMQ Z/OS V7
Fixed component ID
5655R3600
Applicable component levels
R100 PSY UI19842
UP14/08/30 P F408
R101 PSY UI19843
UP14/08/30 P F408
R102 PSY UI19844
UP14/08/30 P F408
R103 PSY UI19845
UP14/08/30 P F408
R104 PSY UI19846
UP14/08/30 P F408
R105 PSY UI19847
UP14/08/30 P F408
Fix is available
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Document Information
Modified date:
12 April 2016