APAR status
Closed as program error.
Error description
IIB v10 changed from using the MQGET API to the MQCTL-MQCB API. These behave very differently with respect to the management of the message buffer. Using the MQGET API, IIB allocated the message buffer storage and also monitored the size of the buffer, resizing it if it was no longer required to be very large. Using the MQCTL-MQCB API, MQ allocates the message buffer and does not provide a means for the application to manage this. The current MQ design for the MQCTL-MQCB API results in the following changes in behaviour that affect the storage usage for IIB message flows processing MQ input messages: 1. MQ allocates the message buffer. On z/OS this is in 31-bit storage. 2. MQ only resizes the buffer up, to the maximum message size that the thread has processed, but it does not resize the buffer down if only smaller messages are subsequently processed. 3. The message buffers remain allocated for the life of the message flow thread. As a result of these changes, an integration server (IS) that regularly processes very large MQ input messages on multiple message flow threads, might experience increased or excessive storage usage for the IS process. On z/OS this can be a particular problem because the MQ buffers are allocated in 31-bit storage which is considerably more limited than 64-bit storage. This can lead to the IS logging the following messages and an 878-10 abend loop: +BIP2628W (Msg 1/2) MQ20BRK EG3 76 EXCEPTION CONDITION DETECTED ON INPUT NODE 'MessageFlow.MQInput'. +BIP2680E (Msg 2/2) MQ20BRK EG3 76 FAILED TO SETUP A MQ CONTROL CALLBACK FOR COMPONENT 'MessageFlow.MQ Input' TO QUEUE 'INPUT' ON QUEUE MANAGER 'MQ20': MQCC=2; MQRC=2195. IEA794I SVC DUMP HAS CAPTURED: DUMPID=007 REQUESTED BY JOB (MQ20BRK ) DUMP TITLE=MQ20,ABN=878-00000010,U=WMQI20,C=W9700.800. MMC -CSQMALCH,M=CSQGFRCV,PSW=070C1000815F4CEE,ASID=00A7 CSQY291E CSQWDSDM SDUMPX FAILED, RC=00003E08,MQ20,ABN=878-00000010, PSW=070C1000815F4CEE,ASID=00A7
Local fix
N/A
Problem summary
**************************************************************** USERS AFFECTED: All users of IBM Integration Bus version 10 using MQInput nodes. Platforms affected: z/OS, MultiPlatform **************************************************************** PROBLEM DESCRIPTION: In version 10, IBM Integration Bus changed from using the MQGET API to the MQCTL-MQCB API. These behave very differently with respect to the management of the message buffer. When using the MQGET API, IBM Integration Bus allocated the message buffer storage and also monitored the size of the buffer, resizing it if it was no longer required to be very large. In contrast, when using the MQCTL-MQCB API, MQ allocates the message buffer and does not provide a means for the application to manage this. The current MQ design for the MQCTL-MQCB API results in the following changes in behaviour that affect the storage usage for IBM Integration Bus message flows processing MQ input messages: 1. MQ allocates the message buffer. On z/OS this is in 31-bit storage. 2. MQ only resizes the buffer upwards to the maximum message size that the thread has processed, but it does not resize the buffer downwards if only smaller messages are subsequently processed. 3. The message buffers remain allocated for the life of the message flow thread. As a result of these changes, an integration server (IS) that frequently processes very large MQ input messages on multiple message flow threads, might experience increased or excessive storage usage for the IS process. On z/OS, this can be a particular problem because the MQ buffers are allocated in 31-bit storage, which is considerably more limited than 64-bit storage. This can lead to the IS logging the following messages and an 878-10 abend loop: +BIP2628W (Msg 1/2) MQ20BRK EG3 76 EXCEPTION CONDITION DETECTED ON INPUT NODE 'MessageFlow.MQInput'. +BIP2680E (Msg 2/2) MQ20BRK EG3 76 FAILED TO SETUP A MQ CONTROL CALLBACK FOR COMPONENT 'MessageFlow.MQ Input' TO QUEUE 'INPUT' ON QUEUE MANAGER 'MQ20': MQCC=2; MQRC=2195. IEA794I SVC DUMP HAS CAPTURED: DUMPID=007 REQUESTED BY JOB (MQ20BRK ) DUMP TITLE=MQ20,ABN=878-00000010,U=WMQI20,C=W9700.800. MMC -CSQMALCH,M=CSQGFRCV,PSW=070C1000815F4CEE,ASID=00A7 CSQY291E CSQWDSDM SDUMPX FAILED, RC=00003E08,MQ20,ABN=878-00000010, PSW=070C1000815F4CEE,ASID=00A7
Problem conclusion
IBM Integration Bus has been modified to: * Resize the buffer on any active threads if it is large and has not been used for a period of time * On z/OS, disconnect from the Queue Manager and so release the buffer for additional instance threads that have idled out. This already occurred for non XA users. On z/OS MQ APAR PI90772 is required in conjunction with IBM Integration Bus APAR PI90759 for this APAR PI90759 to be effective. --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: Version Maintenance Level v10.0 10.0.0.12 The latest available maintenance can be obtained from: http://www-01.ibm.com/support/docview.wss?rs=849&uid=swg27006041 If the maintenance level is not yet available,information on its planned availability can be found on: http://www-1.ibm.com/support/docview.wss?rs=849&uid=swg27006308 ---------------------------------------------------------------
Temporary fix
Comments
APAR Information
APAR number
PI90759
Reported component name
IIB Z/OS
Reported component ID
5655AB100
Reported release
A00
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2017-11-29
Closed date
2018-03-21
Last modified date
2018-03-21
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
IIB Z/OS
Fixed component ID
5655AB100
Applicable component levels
[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSNQH8","label":"IBM Integration Bus for z\/OS"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"10.0","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}},{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG19M","label":"APARs - z\/OS environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"10.0","Edition":"","Line of Business":{"code":"","label":""}}]
Document Information
Modified date:
21 March 2018