A fix is available
APAR status
Closed as new function.
Error description
REAL STORAGE usage statistics. (44080)
Local fix
n/a
Problem summary
**************************************************************** * USERS AFFECTED: All DB2 z/OS V11 users. Requires z/OS * * APAR OA50366 be installed and IFCID0503 * * enabled before non-zero values are returned * * for the new IFCID0225 record fields. * * * * OA50366 may be installed before or after * * PI82191. * **************************************************************** * PROBLEM DESCRIPTION: IFCID225 Real Storage statistics record * * shows the total number of Real Frames * * charged to DB2, but many of these * * frames may have been discarded and are * * available for steal. * **************************************************************** * RECOMMENDATION: * **************************************************************** The IFCID0225 storage statistics record contains field values for the number of Real Storage pages charged to DB2 for 31 and 64-bit virtual. These values are the current high water values and would only be the actual frames in use if the system were actively paging and stealing all of the discarded frames, or the frames have been stolen to replenish the frame available queues. Systems that have large amounts of REAL MAIN MEMORY and never page would likely always display the high water value. When DB2 ZPARM RealStorage_Management is ON or AUTO, contracted pages or pages freed during thread termination, are DISCARDDATA KEEPREAL(YES) and remain backed and charged against DB2 until or unless they are stolen.
Problem conclusion
Temporary fix
Comments
The IFCID0225 record will now contain a new bit flag, QW0225DPGS, indicating this record contains return values for the following new fields: - QW0225ShrStkstg_dpage - QW0225PriStg_dpage - QW0225ShrStg_dpage - QW0225ComStg_dpage These fields will be zero in all records if QW0225DPGS is OFF, or if macro call result return count is zero, or if OA50366 is not applied. The IARV64 COUNTPAGES option, which contains the new DISCARDPAGES(YES) keyword, will be issued only once each day at approximately midnight local time, if new IFCID0503 is active. At the time this function is performed, an increase in DB2 MSTR TCB time will be observed. This increase may be many times the normal observed and is dependent on the amount of 64-bit storage in-use by this member. The collection occurs only once per day due to the cost of the serialization and instructions to return these values for each non-bufferpool object. If RealStorage_management = OFF, or IFCID0503 is OFF, this request will not be issued since there would be no discarded frames or user does not want the data. The above new fields represent the count of DISCARDED frames which have not been stolen or re-referenced since the DISCARD was performed. The actual Real Frames in use at this interval, may be calculated by the following where xxx = any one of the four different new count fields above: QW0225xxxStg_Real + QW0225xxxStg_Aux - QW0225xxxStg_dpage
APAR Information
APAR number
PI82191
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
B10
Status
CLOSED UR1
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2017-05-25
Closed date
2017-07-27
Last modified date
2017-09-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI49142
Modules/Macros
DSNDQWHS DSNDQW03 DSNLTMSC DSNTXSTB DSNVMON DSNWDFSM DSNWVINT DSNWVZXT DSNYASCP
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RB10 PSY UI49142
UP17/08/12 P F708
Fix is available
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Document Information
Modified date:
02 September 2017