A fix is available
APAR status
Closed as program error.
Error description
After PM17542 SMF IO counting at the DB2 address space level is no longer available, which was not the intention.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All DB2 V10 users in z/OS 1.12 or higher. * * * * All DB2 V8 and V9 users with PM17542 * * (UK60887, UK60888) applied in z/OS 1.12 or * * higher. * **************************************************************** * PROBLEM DESCRIPTION: With PM17542 applied, DB2 users may be * * exposed to the z/OS problems: * * * * - Overlay of high private storage with * * a UCB address. ABENDC78-54 when the * * PPD eyecatcher for z/OS SIOTX cell * * pool is overlaid with a UCB address. * * SMCOVERLAY. * * * * Fixed by OA36101 (UA60221 UA60222). * * * * - SMF record type 30 I/O counting info * * at DBM1 address space level may have * * missing counts. SMF30TEP and * * SMF30TEX contain invalid (lower) * * values. * * * * Fixed by OA37361 and OA37362 (UA62296 * * UA62297) * * * * Note: PM17542 is in DB2 V10 base code. * **************************************************************** * RECOMMENDATION: * **************************************************************** PM17542 turns on SVC 99 parameter S99DASUP to suppress DD-level accounting when allocating a data set for a DB2 page set. In this path, the storage overlay problem may occur. The SMF record type 30 I/O counting at the DBM1 address space level is suppressed.
Problem conclusion
The APARs and actions to be taken below are pertaining to DB2 running in z/OS 1.12 or higher only. z/OS APAR OA36101 (allocation) must be installed as soon as possible to fix the potential storage overlay problem. z/OS APAR OA37361 (media manager) and OA37362 (VSAM) together will fix the missing address space level SMF I/O counting problem. DB2 users should install them when available. From the DB2 side, PM46045 is used to provide an alternative for DB2 users to turn off S99DASUP. The code is changed to tie S99DASUP to the setting of MEMDSENQMGMT when allocating a data set for a DB2 page set. S99DASUP is set to on only when MEMDSENQMGMT is enabled. So before the user could find a window to install z/OS fixes, PM46045 could be applied first. By setting MEMDSENQMGMT DISABLE, the two z/OS problems can be avoided. Once all APARs (PM46045, OA36101, OA37361, OA37362) are installed, it is recommended to set MEMDSENQMGMT ENABLE to get the performance benefit. Instructions on setting MEMDSENQMGMT to DISABLE or ENABLE: ========================================================== Work with your system programmer to complete one of the following actions: - Update the ALLOCxx parmlib member to set the SYSTEM MEMDSENQMGMT value. SYSTEM MEMDSENQMGMT(DISABLE) or SYSTEM MEMDSENQMGMT(ENABLE) - Issue system command SETALLOC SETALLOC SYSTEM,MEMDSENQMGMT=DISABLE or SETALLOC SYSTEM,MEMDSENQMGMT=ENABLE Note: 1. Updating the ALLOCxx parmlib is strongly recommended as it remains effective across IPLs. 2. If SETALLOC SYSTEM,MEMDSENQMGMT command is used, a DB2 restart is required to make the change effective. 3. System command D ALLOC,OPTIONS can be used to display the status of MEMDSENQMGMT in z/OS. Sample DISPLAY output: IEFA003I 15.35.15 ALLOC OPTIONS SPACE PRIMARY: 4 SECONDARY: 24 : SYSTEM IEFBR14_DELMIGDS: LEGACY TAPELIB_PREF: EQUAL REMIND_INTV: 90 VERIFY_UNCAT: FAIL TEMPDSFORMAT: INCLUDELABEL MEMDSENQMGMT: ENABLE APARs interactions: =================== The following summarizes the interactions of DB2 APARs PM17542, PM46045, and z/OS APARs OA36101, OA37361, and OA37362. It is intended to help you determine when to apply DB2 and z/OS APARs, and in what order. 1. PM17542 only - exposed to overlay and missing SMF I/O counting at address space level. MEMDSENQMGMT irrelevent. 2. PM17542 with OA36101 - exposed to missing SMF I/O counting at address space level only. MEMDSENQMGMT irrelevent. 3. PM17542 with OA36101, OA37361 & OA37362 - no longer exposed to either problem. 4. PM17542 with PM46045 - S99DASUP setting now only turned on when MEMDSENQMGMT is enabled. Exposed to overlay and missing SMF I/O counting at address space level ONLY when MEMDSENQMGMT is ENABLED. 5. PM17542 with PM46045 & OA36101 - S99DASUP setting now only turned on when MEMDSENQMGMT is enabled. Exposed to missing SMF I/O counting at address space level ONLY when MEMDSENQMGMT is ENABLED. 6. PM17542 with PM46045, OA36101, OA37361 & OA37362 - no longer exposed to either problem. Performance benefits for both features introduced with PM17542 only available when MEMDSENQMGMT is ENABLED.
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PM46045
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
910
Status
CLOSED PER
PE
YesPE
HIPER
YesHIPER
Special Attention
NoSpecatt
Submitted date
2011-08-18
Closed date
2011-10-27
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:
UK73300 UK73301 UK73302
Modules/Macros
DSNB1OST
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RA10 PSY UK73300
UP11/11/11 P F111 ®
R810 PSY UK73301
UP11/11/11 P F111 ®
R910 PSY UK73302
UP11/11/11 P F111 ®
Fix is available
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Document Information
Modified date:
02 December 2011