A fix is available
APAR status
Closed as program error.
Error description
When a queue manager recovers the CF structure (following a cancel of the QMGR and deletion of the structure) it does so by reading through the logs of all QMGRs in the QSG and replaying them. Then the latest backup from the QMGR log which took it is restored. While log replay completes quickly the QMGR recovery of the backup takes much longer. Recovery failure in this scenario is due to insufficient storage in the CF. To avoid this recovery failure of the CF structure the QMGR should connect to the CF structure with a 2:1 element to entry ratio at the time of structure initialization. This will be allowed if at least one of the offloading rules has a threshold and size of zero. ADDITIONAL SYMPTOM 2192 MQRC_STORAGE_MEDIUM_FULL CSQE022E CSQERCF2 Structure x unusable, size is too small ABEND5C6 00C51173 CSQERCF2+000020F0 CSQE035E CSQEQSR1 Structure x in failed state,recovery needed
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 * * Release 1 Modifcation 0. * **************************************************************** * PROBLEM DESCRIPTION: When using SMDS offload with at least * * one of the offload rules having the * * size and threshold set to zero, all of * * the messages will be offloaded and for * * each entry used in the CF structure, * * only 2 elements will be used. When * * ALLOWAUTOALT is not set on the CFRM * * policy, about 60% of space in the * * structure remains unused. * **************************************************************** * RECOMMENDATION: * **************************************************************** The entry to element ratio for a structure is set on the first IXLCONN call. MQ has a fixed 1:6 ratio. However, if all the messages are offloaded to SMDS, each message will use 1 entry and 2 elements to be stored, leaving 4 elements unused per message. If ALLOWAUTOALT is set, the system will determine if the ratio can be optimised when the FULLTHRESHOLD value is reached and reorganise the structure if possible. This would change the entry to element ratio to 1:2 in the mentioned use case. This operation takes time however, and could cause applications to receive 2192 return codes.
Problem conclusion
A service parm was added in this fix to initialise the CF Structure with a 1:2 entry to element ratio if all of the following conditions are true: - The service parm is set - SMDS offload is used, "OFFLOAD(SMDS)" - At least one of the offloading rules has the threshold and size values set to zero, for example "OFFLD1TH(0) OFFLD1SZ(0K)". The service parm should only be used under guidance of IBM support. MQSMDS/K 100Y CSQECONN
Temporary fix
Comments
APAR Information
APAR number
PM77094
Reported component name
WMQ Z/OS V7
Reported component ID
5655R3600
Reported release
100
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2012-11-14
Closed date
2012-12-11
Last modified date
2013-02-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK90218
Modules/Macros
CSQECONN
Fix information
Fixed component name
WMQ Z/OS V7
Fixed component ID
5655R3600
Applicable component levels
R100 PSY UK90218
UP13/01/16 P F301
Fix is available
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Document Information
Modified date:
04 February 2013