IBM Systems Magazine, Mainframe Edition - January/February 2011 - 43

pools with PGFIX(YES) and specify the LFAREA z/OS system parameter. LFAREA is the amount of real storage that z/OS uses for large frames.

RELEASE(DEALLOCATE)
The RELEASE(DEALLOCATE) option has been part of the DB2 \BIND/ REBIND command for a long time, but DB2 10 makes the function more useful. The dramatic Database Services Address Space Parameters (DBM1) virtual-storage constraint relief in DB2 10 achieved with rebind makes it possible to make more use of RELEASE (DEALLOCATE). This change saves up to 10 percent of CPU time for high-volume transactions with short-running SQL, without changing applications or Data Definition Language (DDL).

Distributed Applications
For Distributed Data Facility (DDF) work, after rebinding packages with RELEASE(DEALLOCATE), the customer must issue the MODIFY DDF PKGREL(BINDOPT) command to allow DB2 to use RELEASE(DEALLOCATE) processing for packages bound w it h R E L E A S E ( D E A L L O C AT E ) . DDF inactive thread processing ( C M T S TAT = I N A C T I V E ) t a k e s advantage of new high-performance database-access threads (DBATs) to increase distributed DBAT thread reuse. Implementing the MODIFY DDF PKGREL(COMMIT) command can commit behavior when, for example, you need to allow utilities to break in. With DB2 10 for Linux*, UNIX* and Windows* 9.7 Fix Pack 3, the Call Level Interface (CLI) and JDBC packages are bound with RELEASE(DEALLOCATE) by default. RELEASE(DEALLOCATE) assumes the use of well-behaved applications that adhere to required locking protocols and issue frequent commits. DB2 10 further improves overall Distributed Relational Database

Architecture (DRDA) application performance for result sets from SELECT statements that contain the FETCH FIRST 1 ROW ONLY clause. Simply combine the OPEN, FETCH and CLOSE requests into a single network request. DB2 10 also offers improved DDF performance through restructuring distributed processing on the server, particularly the interaction between the DDF and DBM1 address spaces. Migrating to DB2 10 Conversion Mode, rebinding packages, exploiting large page frames and exploiting RELEASE(DEALLOCATE) can save up to 10 percent of the CPU for transaction workloads and up to 20 percent for native SQL-procedure applications. Much greater CPU savings is possible for queries that contain large numbers of index Stage 1 predicates, as well as IN-list predicates. Also, more Stage 2 predicates can be pushed down to Stage 1.

number of members constant while increasing transaction throughput. If you were previously unable to increase the MAXKEEPD zparm value due to a DBM1 virtual-storage constraint in DB2 9, you may be able to increase MAXKEEPD since the localstatement cache is moved above the bar. Increasing the constraint value may reduce prepares for more SQL statements and provide additional CPU savings.

I/O Improvements
Other CPU improvements apply in more specific scenarios. Some of these are related to I/O improvements since I/Os are one of the significant consumers of CPU time. These include an improved, dynamic prefetch sequential-detection algorithm. List prefetch support for indexes helps minimize index I/Os when scanning a disorganized index. The number of log I/Os is also reduced and long-term page fixing of the log buffers saves CPU time as well.

Capacity Improvements
Since most of the thread storage has been moved above the bar, DB2 10 can support more threads than DB2 9, thereby making it possible to reduce the number of DB2 datasharing members, or at least hold the

zIIP and zAAP Exploitation
Buffer pool prefetch and deferred write Supervisor Request Blocks (SRBs) ordinarily aren’t big CPU consumers, but DB2 10 makes this

Figure 1
Average percent of CPU improvement

ibmsystemsmag.com/mainframe

JA N UA RY/ FE B RUA RY 2 011

43



IBM Systems Magazine, Mainframe Edition - January/February 2011

Table of Contents for the Digital Edition of IBM Systems Magazine, Mainframe Edition - January/February 2011

IBM Systems Magazine, Mainframe Edition - January/February 2011
Table of Contents
On the Web
Editor's Desk: Time is Expensive
Data Display: Utilities, Users and Devices Are Getting Energy Wise Are Getting Energy Wise
Think Smarter: Smart Storage Solutions Let You Have It All
Insider: Energy Efficiency is More Than an Optimized Server
Trends: Case Study Shows IBM’s zEnterprise System Reduces Costs Across the Business
Moving Forward: UniGroup Inc. develops a mainframe-based Web tool to create a more flexible business model.
Tipping the Scale: Labor expenses should influence IT acquisition decisions.
Four-Star Advantage: The Polaris Workshop maps out a custom platform strategy.
Tips and Techniques: Reduce Resource Consumption on DB2 10 for z/OS
Solutions
Advertisers' Index
Stop Run: System/360 Pioneer Fred Brooks Teaches Design That Still Shapes Computing
IBM Systems Magazine, Mainframe Edition - January/February 2011 - IBM Systems Magazine, Mainframe Edition - January/February 2011
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Cover2
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 1
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 2
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 3
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Table of Contents
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 5
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 6
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 7
IBM Systems Magazine, Mainframe Edition - January/February 2011 - On the Web
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 9
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 10
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 11
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Editor's Desk: Time is Expensive
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 13
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Data Display: Utilities, Users and Devices Are Getting Energy Wise Are Getting Energy Wise
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 15
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Think Smarter: Smart Storage Solutions Let You Have It All
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 17
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 18
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 19
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Insider: Energy Efficiency is More Than an Optimized Server
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 21
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 22
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 23
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Trends: Case Study Shows IBM’s zEnterprise System Reduces Costs Across the Business
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 25
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 26
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 27
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Moving Forward: UniGroup Inc. develops a mainframe-based Web tool to create a more flexible business model.
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 29
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 30
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 31
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Tipping the Scale: Labor expenses should influence IT acquisition decisions.
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 33
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 34
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 35
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Four-Star Advantage: The Polaris Workshop maps out a custom platform strategy.
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 37
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 38
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 39
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 40
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 41
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Tips and Techniques: Reduce Resource Consumption on DB2 10 for z/OS
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 43
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 44
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Solutions
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Advertisers' Index
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Stop Run: System/360 Pioneer Fred Brooks Teaches Design That Still Shapes Computing
IBM Systems Magazine, Mainframe Edition - January/February 2011 - 48
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Cover3
IBM Systems Magazine, Mainframe Edition - January/February 2011 - Cover4
IBM Systems Magazine, Mainframe Edition - January/February 2011 - RF1
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