A fix is available
APAR status
Closed as program error.
Error description
In CICS TS 3.2 the size of the handle table block increase beyond 2K which is beyond the limit of the quickcell getmain. This fix will implement an alternative caching mechanism to improve the performance of HTB handling.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All. * **************************************************************** * PROBLEM DESCRIPTION: Performance degradation due to HTBs * * exceeding the 2K size limit for * * quickcell GETMAINs. * **************************************************************** * RECOMMENDATION: * **************************************************************** In CICS TS 3.2 the size of the handle table block (HTB) increased beyond 2K, which is beyond the limit of the quickcell GETMAIN. Whenever a HTB was required a domain call to SMGF was issued for the GETMAIN. The pathlength for a full domain call getmain is significantly more than the quickcell GETMAIN. HTBs are required for program links which issue EXEC CICS HANDLE commands, therefore the cumulative effect of this can be significant. In performance testing an increase of up to 0.5% CPU was observed compared with previous releases. Additional keywords: performance program link HTB HANDLE PUSH AID CONDITION degradation
Problem conclusion
This fix is to implement a caching mechanism for HTBs. When HTBs are released they are saved on a chain for the task. Where possible, HTBs are obtained from the task chain rather than an SMGF GETMAIN. For programs with multiple links which issue EXEC CICS HANDLE or EXEC CICS PUSH HANDLE commands, this will significantly reduce the cost of acquiring an HTB. The CICS Transaction Server for z/OS Version 3 Release 2 Supplementary Data Areas manual, GC34-6864-00, has been altered on page 286 to add new field HTB_NEXT_FREE to the Handle Table Block (HTB). HTB_NEXT_FREE overlays the existing field HTB_PREV_TABLE, therefore the following has been added infront of HTB_PREV_TABLE at offset X'10': Offset Type Len Name (Dim) Description Hex (10) ADDRESS 4 HTB_NEXT_FREE -> next free htb The same manual has also been altered on page 774 to add new field PTA_FREE_HTB_CHAIN to the end of the PTA (PG Transaction Area) control block at offset X'50' as follows: Offset Type Len Name (Dim) Description Hex (50) ADDRESS 4 PTA_FREE_HTB_CHAIN -> htbs (54) CHARACTER 0 *
Temporary fix
********* * HIPER * ********* FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PK48164
Reported component name
CICSTS V3 Z/OS
Reported component ID
5655M1500
Reported release
500
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt
Submitted date
2007-07-02
Closed date
2007-08-20
Last modified date
2007-09-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK28329
Modules/Macros
DESHMDC DESHMP DESPGDC DESPGDUF DESPGHM DESPGXM DFHHMDCC DFHHMDCD DFHPGDCC DFHPGDCD DFHPGDM DFHPGDUF DFHPGHM DFHPGXM
GC34686400 |
Fix information
Fixed component name
CICSTS V3 Z/OS
Fixed component ID
5655M1500
Applicable component levels
R500 PSY UK28329
UP07/08/24 P F708
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:
04 September 2007