A fix is available
APAR status
Closed as program error.
Error description
A region has suffered an out of space condition on the auxiliary temporary storage dataset. Right after this condition occurred there are multiple exception monitoring records being cut. Upon further review of CICS Internal Trace shows a task being purged and all the tasks waiting for AUX_SPACE are given the chance to run again. This is the design mechanism that temporary storage uses when giving other tasks the chance to run. The logic in DFHTSWQ will make an exception data put call to monitoring domain, and this is in turn visible in the trace entries for APEX for XMNOUT. Giving every task the chance to run again allows the CICS dispatcher to honor dispatching priorities when allocating which task gets the chance to run next and get the resource in question. Normally there are relatively few waiters and the effect of resuming them all does not have that great of impact on a system. For this instance the logic path for recovery following a timeout on a write invokes the same method as used for basic delete processing. In the case of a queue deletion it makes sense to resume all waiters for storage on DFHTEMP. But in the case of a write that has timed out it will not have freed up storage on DFHTEMP. In this particular case, there is no benefit to resuming any waiters, and doing so would indeed lead to unfavorable conditions. Additional Symptom(s) Search Keyword(s): KIXREVRHC
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All * **************************************************************** * PROBLEM DESCRIPTION: Unnecessary resumes of tasks waiting * * for TSAUX storage. * **************************************************************** * RECOMMENDATION: * **************************************************************** When a writeq times out or is purged while waiting for auxiliary temporary storage to become available, routine tsaux_delete will resume all waiters for TSAUX. These tasks are redispatched, but will typically fail to find any freed-up space on DFHTEMP, so have to resuspend on TSAUX once more. This leads to churn within CICS and unnecessary CPU being used.
Problem conclusion
DFHTSQR has been changed to only resume waiters if space has been freed up as part of the tsaux_delete processing.
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PM48753
Reported component name
CICS TS Z/OS V4
Reported component ID
5655S9700
Reported release
600
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2011-09-27
Closed date
2011-11-21
Last modified date
2011-12-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK73953 UK73954
Modules/Macros
DESTSAM DESTSQR DFHTSAM DFHTSAMC DFHTSBR DFHTSCL DFHTSDM DFHTSDUC DFHTSDUF DFHTSDUS DFHTSPT DFHTSQR DFHTSRM DFHTSST
Fix information
Fixed component name
CICS TS Z/OS V4
Fixed component ID
5655S9700
Applicable component levels
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 2011