flodubois 270000K6H5 Visits (308)
A new version of MEMU2 for DB2 10 is now available. MEMU-V10-V2.zip can be downloaded from the developerWorks website.
Michael_D. 1100004WAH Visits (775)
Michael_D. 1100004WAH Visits (1524)
DB2 10 can reduce the total DB2 CPU demand from 5-20% when you take advantage of all the enhancements. Many CPU reductions are built in directly to DB2, requiring no application changes. Some enhancements are implemented through normal DB2 activities through rebinding, restructuring database definitions, improving applications, and utility processing. The CPU demand reduction features have the potential to provide significant total cost of ownership savings based on the application mix and transaction types.
Improvements in optimization reduce costs by processing SQL automatically with more efficient data access paths. Improvements through a range-list index scan access method, list prefetch for IN-list, more parallelism for select and index insert processing, better work file usage, better record identifier (RID) pool overflow management, improved sequential detection, faster log I/O, access path certainty evaluation for static SQL, and improved distributed data facility (DDF) transaction flow all provide more efficiency without changes to applications. These enhancements can reduce total CPU enterprise costs because of improved efficiency in the DB2 10 for z/OS.
DB2 10 includes numerous performance enhancements for Large Objects (LOBs) that save disk space for small LOBs and that provide dramatically better performance for LOB retrieval, inserts, load, and import/export using DB2 utilities. DB210 can also more effectively REORG partitions that contain LOBs.
This IBM Redbooks® publication® provides an overview of the performance impact of DB2 10 for z/OS discussing the overall performance and possible impacts when moving from version to version. We include performance measurements that were made in the laboratory and provide some estimates.
Keep in mind that your results are likely to vary, as the conditions and work will differ.
In this book, we assume that you are somewhat familiar with DB2 10 for z/OS.
See DB2 10 for z/OS Technical Overview, SG24-7892-00, for an introduction to the new functions.
Michael_D. 1100004WAH Visits (2825)
PM56845: PROVIDE OPTION FOR OPTIMIZE FOR 1 ROW TO ALLOW SOME SORT ACCESS PATHhtt
In all versions of DB2, the OPTIMIZE FOR 1 ROW clause requests DB2 to choose an access path that avoids a sort. In DB2 versions prior to 10, there is a possibility to obtain an access path with a sort even though that path is strongly discouraged. In DB2 10, DB2 will not compete access paths with sorts and will instead choose the lowest cost access path that does not require a sort.
This APAR provides an option to return to the previous version OPTIMIZE FOR 1 ROW behavior. As such, it does not eliminate the risk of an inefficient access path being chosen with OPTIMIZE FOR 1 ROW when the efficient access requires a sort. However, it does limit that exposure to what already existed in DB2 prior to DB2 10.
For queries that need sorts, the recommended solution is to avoid coding the OPTIMIZE FOR 1 ROW clause. Without the OPTIMIZE FOR 1 ROW clause, DB2 will choose access paths based on cost and will not make an effort to avoid sorts.
Local work around:
For queries that need sorts for efficient access, the solution is to avoid coding the OPTIMIZE FOR 1 ROW clause.
Change application to code OPTIMIZE FOR 2 ROWS
Wait for APAR PM56845 that is now open to provide option for OPTIMIZE FOR 1 ROW to allow sort access plans
Michael_D. 1100004WAH Visits (2415)
PM24723: IFCID 225 REAL STORAGE STATISTICS ENHANCEMENTS IFCID225
DB2 APAR PM24723 is very important and supports REAL STOARAGE monitoring issue via a new extension to IFCID 225
See z/OS APAR z/OS APAR OA37821 and corresponding DB2 APAR PM49816 for this issue
OA37821: NEW FUNCTION IARV64 REQUEST=COUNTPAGES SUPPORT FOR UNSERIALIZED PROCESSING.
Useful commands monitoring the use of 1MB size real storage page frames on z10 and z196 :
DISPLAY BUFFERPOOL(BP1) SERVICE=4
Display provides output via DSNB999I messages of how many 1MB size page frames are being used
This z/OS command shows the total LFAREA, allocation and splits it across 4KB and 1MB size frames, via IAR019I message
Michael_D. 1100004WAH Visits (2536)
agburke 060001QPDN Visits (143)
Here are some informational APARs regarding DB2 11 and distributed processing.
Remember that DB2 Connect V10.5 FP2 is the recommended level to exploit DB2 11 new features.
flodubois 270000K6H5 Visits (458)
OMPE recently delivered a very useful functionality for anyone who wants to track the evolutionary trend of key performance metrics. The new OMPE Spreadsheet Input Data Generator can be used to generate a CSV (comma-separated value) file containing a chosen subset of statistics or accounting indicators. The default field selection includes all the fields that have a column in the associated OMPE Performance database (PDB) table, but these lists can easily be customized to meet your own needs for reporting. This CSV data can then be transferred to workstations and imported into spreadsheets to improve DB2 performance analysis using graphical representations or pivot tables.
Requirements: APAR PM73732 and OMPE v510 PTF UK90267 / OMPE v511 PTF UK90268
flodubois 270000K6H5 Visits (707)
To help you convert your plans and packages from using private protocol to using DRDA protocol, DB2 provides a priv
The tool will inserts a '*' in place of an empty value in the location part of any PKLIST entry. If you use an asterisk, at run time the location comes from the special register CURRENT SERVER and DB2 checks privileges to use the SQL statements in the package at that location. This could result in a significant increase in authorization checks and lead to an important CPU overhead.
Michael_D. 1100004WAH Visits (702)
Michael_D. 1100004WAH Visits (872)
DB2 9, which GA'd back in March 2007, is replaced by DB2 10 for z/OS (5605-DB2). For further information, please refer to the announcement letters accessible via these links:
Michael_D. 1100004WAH Visits (1275)
PM42528: SUPPORT FOR DELETING A MEMBER FROM A DATA SHARING GROUP
To use this support:
- The APAR or PTF providing delete member support must be applied to all members. Since deleting a member requires all members to be stopped, there is no pre-conditioning APAR / PTF.
- The member being deleted must be quiesced with no outstanding units of work, active utilities or retained locks.
- There should be no objects in restricted states. Use the -DISPLAY DATABASE(*) RESTRICT to verify.
- All surviving members must be DB2 10 New Function Mode
- The member to be deleted must be quiesced at some point before the surviving members are stopped so that the quiesced state is saved in all the surviving members' BSDSs.
- Stop all members of the data sharing group.
- Make backup copies of all BSDSs.
- Run the change log inventory (DSNJU003) DELMBR control statement against all the group members' BSDSs to deactivate the member that is to be deleted.
- Restart the surviving members of the group.
- When the logs of the member to be deleted are no longer needed, proceed.
- Stop all members of the data sharing group.
- Make backup copies of the BSDSs.
- Run the change log inventory (DSNJU003) DELMBR command against all the group members' BSDSs to destroy the member that is to be deleted.
- Restart the surviving members of the group.
- After all surviving members have been restarted, the logs and BSDS of the deleted member are no longer needed.
DELETE data sharing member related APAR's and PTF's
APAR : PM31003, PM31004, PM31006, PM31009
PTF : UK67512, UK67958, UK69286, UK65750
GZJ 1100006WMT Visits (106)
Customers who are using VSAM log striping for the DB2 active log datasets with DB2 10 for z/OS or DB2 11 for z/OS should pay attention to recently opened APAR PI10353, which is now marked HIPER. There is no exposure for DB2 for z/OS customers running DB2 V9.1 or earlier. Neither is there any cause for alarm, as the exposure for DB2 10 or 11 is very small. There is no data loss involved and no loss of data integrity.
KateWheat 060000T8JC Visits (166)
Access to IBM information centers will soon be redirected to IBM Knowledge Center, so take time now to explore your favorite IBM information in its new home at ibm.biz/IBMKCgo. If you've explored IBM Knowledge Center during its open beta, you have probably noticed some differences from the IBM information centers that you used in the past. With time and practice, using IBM Knowledge Center will become second nature. In the mean time, here are a few tips and techniques that you might be delighted to discover!
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Remember that access to IBM information centers will soon be redirected to IBM Knowledge Center, so take time now to explore your favorite IBM information in its new home at ibm.biz/IBMKCgo.
agburke 060001QPDN Visits (130)
IFCID 199 statistics are externalized on boundaries based on the statistics interval and a grouping of data sets having more than 1 I/O per second. Thus statistics for that data set may not be externalized at the statistics interval boundary. This can cause some confusion when monitoring for specific data sets requiring I/O.
From the APAR text:
New field QW0199SC has been added to the data section 3 of the IFCID 199. This field contains the timestamp of the last time the corresponding dataset statistics were externalized. If this is the first time statistics for this dataset are externalized, this value is a timestamp of when this dataset was opened.