A fix is available
APAR status
Closed as program error.
Error description
Enhance Db2 real storage management when using ZPARM REALSTORAGE_MANAGEMENT = AUTO (default).
Local fix
N/A
Problem summary
**************************************************************** * USERS AFFECTED: * * All Db2 12 for z/OS users. * **************************************************************** * PROBLEM DESCRIPTION: * * Enhance Db2 REALSTORAGE_MANAGEMENT * * subsystem parameter * **************************************************************** * RECOMMENDATION: * * Apply corrective PTF when available * **************************************************************** There are Db2 users who saw significant increase in Db2 system service address space (SRB) CPU time. This has been observed as one of the effects when processing excessive IARV64 REQUEST(DISCARDDATA) requests.
Problem conclusion
The use of the Db2 REALSTORAGE_MANAGEMENT subsystem parameter was enhanced as follows: * introduce a new option AUTO1: This new option will have the same behavior as AUTO prior to applying this PTF (PH47163) * modified behavior of option AUTO: Option AUTO will now check the available real storage on the LPAR. REALSTORAGE_MANAGEMENT=AUTO was specified but Db2 detected that the available real storage on the LPAR is more than the calculated threshold (REALAVAIL > MAXSPACE*1.2), Db2 switches behavior as if option OFF is specified, and does not discard unused real storage. Otherwise, Db2 will behave as if AUTO1 is specified * new message DSNS006I: New message, DSNS006I, will be issued when Db2 switches behavior The recommendation is to continue to use the current REALSTORAGE_MANAGEMENT setting, whether it be OFF, AUTO or ON. This PTF only changes the behavior for users whose current REALSTORAGE_MANAGEMENT setting is AUTO. After applying this PTF (PH47163), those users will see more dynamic use of discarddata processing. This is expected to have positive effect on Db2 MSTR CPU time. Users executing with REALSTORAGE_MANAGEMENT=AUTO, who want to continue to have identical REALSTORAGE_MANAGEMENT behavior prior to applying this PTF (PH47163), must change the REALSTORAGE_MANAGEMENT subsystem parameter setting to AUTO1. DSNS006I csect DB2 WILL START TO BEHAVE AS REALSTORAGE_MANAGEMENT = value Explanation This message is issued when Db2 has detected one of the following conditions was satisfied and caused Db2 to change its behavior OFF = REALSTORAGE_MANAGEMENT=AUTO was specified but Db2 detected that available real storage on the LPAR is more than the calculated threshold (REALAVAIL > 1.2*MAXSPACE) AUTO1 = REALSTORAGE_MANAGEMENT=AUTO was specified but Db2 was behaving as if REALSTORAGE_MANAGEMENT=OFF. Now, the available real storage on the LPAR is no longer more than the calculated threshold (REALAVAIL < 1.2*MAXSPACE), Db2 will behave as REALSTORAGE_MANAGEMENT=AUTO1 OR REALSTORAGE_MANAGEMENT=AUTO but the available real storage on the LPAR is less than or equal to the calculated threshold (REALAVAIL < 1.2*MAXSPACE), Db2 will behave as REALSTORAGE_MANAGEMENT=AUTO1 Where REALAVAIL The amount of real storage currently available on the LPAR MAXSPACE z/OS setting that restricts the virtual storage available to the DUMPSRV address space to capture SVC dumps. For more information about this enhancement, see the description of this APAR in the Db2 for z/OS documentation: https://www.ibm.com/docs/en/SSEPEK_12.0.0/wnew/src/tpc/ db2z_12_newfunctionapars.html Additional Keywords: DSNS006I REALSTORAGE_MANAGEMENT
Temporary fix
Comments
×**** PE23/03/15 FIX IN ERROR. SEE APAR PH53275 FOR DESCRIPTION
APAR Information
APAR number
PH47163
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
C10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2022-06-13
Closed date
2023-01-25
Last modified date
2023-05-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI90276
Modules/Macros
DSN6SPRM DSNFSDIR DSNSVSFM DSNSVSVP DSNSCON2 DSNDQWPZ DSNWZIFC DSNFCDIR DSNVMON DSNDSPRM DSNTIPE1
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RC10 PSY UI90276
UP23/02/14 P F302
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:
03 May 2023