DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

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10.1 DB2 Estimator DB2 Estimator V8 is a no charge tool provided by DB2 to help you predict the performance and cost of running DB2 applications and utilities under DB2 UDB for z/OS. This tool can be downloaded from the URL: http://www.ibm.com/software/data/db2/zos/estimate/ With DB2 Estimator you create definitions of DB2 objects, SQL statements, transactions, utilities, and system configurations. You also have the option to combine elements to form a workload which can be a representative sampling of an application. DB2 Estimator uses this information as input to provide performance estimates which you can use for tuning and also for capacity planning. You can also estimate the disk space used for tables and indexes. DB2 Estimator calculates CPU time, I/O time, and elapsed time for utilities, SQL statements, transactions, and whole applications. The tool gives you the ability to experiment with DB2 applications and utilities on a PC without the need to use DB2. If you want to estimate DB2 V8 functions, then you need to create a new project and specify that you are using DB2 V8. Tip: This can be done in two ways. You can create a new project or copy an existing project using “save as”. In both cases, specify you are using DB2 V8. The DB2 Estimator formulas have been updated to reflect DB2 V8 CPU times. There is support for a limited number of new DB2 V8 features. Check the Web site for an up-to-date list. 10.2 DB2 Performance Expert One of the premier products for performance monitoring is the DB2 Performance Expert (PE). This product has many different components providing a robust set of monitoring functions for viewing your DB2 subsystems. Here is a list of some of the most important functions DB2 PE provides as a monitoring tool: ► ISPF host online monitor ► Workstation online monitor with the capability to monitor all of your DB2 subsystems in a single view ► Exception processing which handles both event and periodic exceptions ► Batch reporting capability for all sorts of reports using DB2 trace data as input ► Performance Database which is a repository for DB2 trace data controlled by the user ► Performance Warehouse which is a repository for DB2 accounting and statistics trace data controlled by PE ► Buffer Pool Analysis to analyze your buffer pool configuration and make recommendations for improvement For more information about this DB2 tool, see: http://www.ibm.com/software/data/db2imstools/ or refer to the book, DB2 Performance Expert for z/OS Version 2, SG24-6867-01, for details on the tool. 364 DB2 UDB for z/OS Version 8 Performance Topics
The following changes to DB2 V8 have been incorporated into the batch reporting function of DB2 PE after publication of that book: ► Performance Expert PTF UQ90726 for APAR PQ88224 supports the ACCUMACC parameters in Batch Accounting reports, such that fields which are not valid for roll-up are shown as N/P or N/C (not present or not calculated). These fields are shown in the latest version of the DB2 Performance Expert Reporting User's Guide, SC18-7978, in Appendix D. Note: The recent DB2 APAR PQ90547 contains some rework on the roll-up mechanism which will be reflected in a Performance Expert PTF targeted for March/April 2005. ► Performance Expert PTF UQ93207 for APAR PQ94872 supports new counters of IFCID 225 for real storage statistics and dynamic statement caching introduced recently by DB2 in PQ91101. In addition, the PTFs provide enhanced support for V8 changes available in Record Trace, System Parameter and EXPLAIN reports. The following new major PE functions have been delivered with PTF UQ95694 for APAR PQ95989 in December 2004: ► READS support of IFCID 225 in Workstation Online Monitor ► Enhancements in Locking Suspension Reports to accumulate additional locking data and write it into a file which can be imported into a spreadsheet for further analysis ► Enhancements in SQL Activity Reports for displaying information on host variables ► Enhancements in I/O Activity Reports supporting new ORDER functionality Virtual storage layout With PQ91101, DB2 introduces new counters in IFCID 225 for real storage statistics and dynamic statement caching. DB2 Performance Expert V2.1 supports this functionality with PTF UQ93207 for APAR PQ94872. See also 4.3, “Monitoring DBM1 storage” on page 157, and Appendix B, “The DBM1 storage map” on page 393. Here is a summary of the features: ► Record Trace The report block for IFCID 225 has been rearranged to better match the layout in the statistics reports. ► Statistics Report and Trace (long format) The report blocks have been implemented as follows: – DBM1 AND MVS STORAGE BELOW 2 GB This block contains the new fields related to dynamic statement caching. Two new fields AVERAGE THREAD FOOTPRINT (MB) and MAX NUMBER OF POSSIBLE THREADS have been added. Here are the formulas: Average Thread Footprint: (QW0225VR - QW0225AS) / (QW0225AT + QDSTCNAT) Max number of possible threads: ((QW0225RG – QW0225EL) – (200 * (1024 * 1024)) – (QW0225GM + QW0225GS + QW0225FX)) / average thread footprint (The block has been split up because the page size limit has been reached.) – DBM1 STORAGE ABOVE 2 GB The block has been extended to contain the field QW0225SJ with label STAR JOIN MEMORY POOL (MB). Chapter 10. Performance tools 365
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ibm.com/redbooks Front cover DB2 UD
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Note: Before using this information
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2.5.3 Increased number of deferred
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4.5.2 Conclusion . . . . . . . . .
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7.4.1 ODBC Unicode support . . . .
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x DB2 UDB for z/OS Version 8 Perfor
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3-48 Consistency query - 31 New . .
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xiv DB2 UDB for z/OS Version 8 Perf
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8-5 CF Request Batching - DB2 CPU .
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xviii DB2 UDB for z/OS Version 8 Pe
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Trademarks The following terms are
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Added information The following APA
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► Added reference to June 15, 200
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Michael Parbs is a DB2 Specialist w
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Hugh Smith Jim Teng John Tobler Yoi
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xxx DB2 UDB for z/OS Version 8 Perf
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1.1 Overview 1.1.1 Architecture IBM
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- Column data type changes can be d
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1.1.3 Data warehouse 1.1.4 Performa
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Volatile (or cluster) tables, used
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In this chapter we anticipate the a
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2.1.3 I/O time 2.1.4 Virtual storag
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► The performance benchmarks for
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application that can have great pot
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Because you can significantly incre
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The possible increase in thread foo
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2.5.9 Unicode parser Important: Con
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You can keep the DBRMs in EBCDIC fo
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Macro Parameter Old value New value
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28 DB2 UDB for z/OS Version 8 Perfo
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► Parallel sort enhancement Paral
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Characteristics of the host variabl
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3.1.4 Performance Update 10 rows us
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► Complexity of the fetch. The fi
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► More rows per one SQL statement
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3.2.1 Creating MQTs MQTs compared t
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Special register CURRENT REFRESH AG
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the materialized query table. If it
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Figure 3-9 MQTs and short running q
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► The elapsed time is 22 times sm
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Figure 3-13 Regrouping on MQT resul
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EVE.EXT = 'ADD BILL' AND EVE.TXC =
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Star Schema Figure 3-15 Star schema
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merge joins and work file usage. DB
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Star join access path without a spa
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3.3.4 Performance Sparse index for
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V8 Star Join Access Path Figure 3-2
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3.3.5 Conclusion Star join workload
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. SELECT * FROM PAOLO.TORDER WHERE
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But not all mismatched numeric type
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V8 shows that PL is joined with CV
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Query performance problem Lack of m
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3.5.1 Performance SORTDEVT SYSDA IN
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3.5.2 Conclusions Figure 3-31 Acces
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Mismatched data types SELECT COUNT(
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3.7.1 Performance In V8 the paralle
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3.7.2 Conclusions Example 3-9 Multi
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3.8.2 Performance We show three exa
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3.8.3 Conclusion The measurements s
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100 Inserts activated trigger 100 t
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3.10.2 Conclusion 100 Inserts activ
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stores the selected columns from ea
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While there is no optimistic lockin
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FETCH FROM Figure 3-45 FETCH syntax
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► Measurement data collected with
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application has decidedly higher Cl
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Static updatable cursor You can see
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Multi-row FETCH with a static curso
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3.12.5 Conclusion Multi-row FETCH a
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While, for or SELECT ... FROM ...
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3.14.2 Conclusion Percent reduction
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3.15.1 Installation commands. Of co
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Figure 3-47 Explain of the old cons
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in ms = 1 and the CPU cost is 16 se
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Figure 3-50 Suggested RUNSTATS stat
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Looking at the explanation, we can
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The Plug-In Options screen of Stati
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Before the introduction of MQTs, DB
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126 DB2 UDB for z/OS Version 8 Perf
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► Larger VSAM CI sizes: DB2 V8 in
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4.1.1 Performance support caused al
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Regression is about 5% better than
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The results indicate no significant
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Important: 4.1.2 Conclusion If you
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However, the combined impact of oth
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Frees up space below the bar for ot
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from the hiperpools, they were not
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So, we advise you to not overalloca
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See 4.3, “Monitoring DBM1 storage
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Table 4-4 System storage configurat
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Stack 11356 21033 85% 8648 19799 12
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KB 600 500 400 300 200 100 0 Figure
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For the same buffer pool size and o
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4.2.3 Conclusion Nondistributed per
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Important: With PTFs UK04394 (DB2 V
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- DATASPACE BP CONTROL BLOCKS = 0 M
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The EXTENDED REGION SIZE (MAX) is t
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RDS OP POOL (MB) N/A RID POOL (MB)
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As you can now appreciate, it is im
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Megabytes A V7 Customer DBM1 Thread
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4.5.1 Performance The most buffer p
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4.6.1 Performance maintained in a 2
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4.6.2 Conclusion We can conclude th
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service for Unicode conversions, an
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overcome this, when DB2 Connect is
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INSERT HV1 1200 HV2 1200 SELECT HV1
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AIX C-program Conversion Routines P
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4.7.1 Performance The improvements
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In October 2003, a new enhancement
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UseServerEncoding data source prope
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4.8.1 Performance 4.8.2 Conclusion
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Multilevel security with row-level
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► The security level that defines
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DB2 must call RACF for this dominan
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4.9.2 Conclusion The CPU increase c
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4.10.1 Performance VSAM does not kn
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4.10.2 Conclusion 4.10.3 Striping A
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5 4 3 2 1 0 9109TLLB 4 Parallel DB2
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This message is completed with the
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This enhancement is introduced by P
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This record is activated by: -START
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an online transaction with very sim
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5.1 System level point-in-time reco
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BACKUP SYSTEM During backup DB2 rec
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Figure 5-1 FRBACKUP PREPARE elapsed
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Figure 5-4 BACKUP SYSTEM FULL measu
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5.1.2 Conclusion The BACKUP SYSTEM
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Figure 5-7 shows the sliding scale
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Maybe you have implemented a space
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For dynamically prepared queries, D
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► CHAR(8) to VARCHAR(8) ► CHAR(
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Before ALTER INDEX add column, a ta
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30 25 20 15 10 Figure 5-12 FETCH CP
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Percent of index pages Avg. Index L
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300 250 200 time in seconds 150 100
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REORG REBALANCE We executed and mea
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5.4 Volatile table 5.4.1 Conclusion
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If explicit clustering for a table
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Load table of 20M rows, 10 partitio
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Times in seconds 20 18 16 14 12 10
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RUNSTATS INDEX PARTITION of a DPSI
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Note that when the qualified partit
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► “NO” - Values in such colum
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5.6.10 Support for more than 245 se
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6.1 Online CHECK INDEX Online CHECK
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SORTOUT DD UNIT=SYSDA,SPACE=(CYL,(5
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- SORT 6 indexes in parallel - CHEC
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make DB2 take the maximum paralleli
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6.3 LOAD and UNLOAD delimited input
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6.3.2 Conclusion We measured the CP
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Options for cardinality and distrib
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► Number of column groups: 1 ►
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cases is the total time of RUNSTATS
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6.4.5 Conclusion Statistics Advisor
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goals for end-user services. We sho
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alanced across all members. With th
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method. Prior to DB2 V8 those array
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when compared to DB2 V7. At the ser
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7.2.2 Performance - Distributed cli
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Recommendation If you currently do
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► The DB2 Universal JDBC type 4 D
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WebSphere z/OS - DB2 z/OS V8 - Serv
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DB2 Universal Type 4 Driver - JDBC
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Use DB2 Connect when a high amount
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JCC Type 4 Direct 4:3 Concentration
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The SYSIBM.INDOUBT table and the pa
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Batch updates A batched update is a
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Example In DB2 V8 SQL/XML publishin
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INSERT INTO PUB_TAB(DOC) SELECT XML
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7.5.3 Conclusion The new XML publis
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Page 352 and 353: Impact on coupling facility: You do
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Page 366 and 367: Table 8-12 DB2 I/O CI Limit Removal
Page 368 and 369: 8.5 Miscellaneous items In this sec
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Page 374 and 375: 9.1 Unicode catalog DB2 for z/OS su
Page 376 and 377: that all applications are converted
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Page 380 and 381: From these measurements we observe
Page 382 and 383: Class 1 CPU time (MSEC) 200 150 100
Page 384 and 385: dynamic statement cache. If activat
Page 386 and 387: that everything is ready. This step
Page 388 and 389: Table Number of rows SYSDATABASE 75
Page 390 and 391: In Figure 9-7 we describe the perfo
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Page 410 and 411: A.1 Maintenance for DB2 V8 The APAR
Page 412 and 413: APAR # Area Text PTF and Notes PQ88
Page 416 and 417: APAR # Area Text PTF and Notes PK21
Page 426 and 427: B.1 DB2 PE Storage Statistics trace
Page 428 and 429: Storage heading Description 24 BIT
Page 432 and 433: C.1 DB2 SQL PA additional reports N
Page 434 and 435: |is the last matching predicate. Ap
Page 436 and 437: |ANL6052I *** NOTE: | |This index i
Page 438 and 439: PREDICATE ANALYSIS ----------------
Page 440 and 441: D.1 DB2 EXPLAIN EXPLAIN describes t
Page 442 and 443: Table D-2 PLAN_TABLE contents and b
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Column Type Content OPTHINT CHAR(8)
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D.1.3 DSN_FUNCTION_TABLE You can us
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Example: D-1 Creating DSN_STATEMENT
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Column Type Content BIND_QUALIFIER
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ICF integrated catalog facility ICF
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► DB2 UDB for z/OS V8: Through th
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character set 174 CHECK DATA 262 CH
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Equi-join predicates 54, 402 Equiva
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MINSTOR 145-146 Mismatched data typ
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PQ84160 378, 387 PQ85764 387 PQ8584
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Sort tree nodes 144 SORTDATA 268 SO
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306 Universal Driver for SQLJ and J
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DB2 UDB for z/OS Version 8 Performa
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