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

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In Figure 9-7 we describe the performance of the migration from V8 CM to V8 NFM, with that you can find out how long it will take you to migrate your catalog from CM to NFM. You just need to find the size of your catalog. Time in Seconds 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 Figure 9-7 Migration from CM to NFM Note: The major component of job DSNTIJNE is the Online Reorg of SPT01 and the 17 catalog table spaces. Job DSNTIJNE performs several functions: ► Saves the current RBA or LRSN in the BSDS ► Changes types and lengths of existing catalog columns ► Converts catalog data to Unicode ► Changes buffer pools for several catalog table spaces ► Changes catalog indexes with varying length columns to NOT PADDED ► Changes page size of several catalog table spaces This job can be run at any time. To stop it, you cannot use a - TERM UTIL command, you need to use job DSNTIJNH. When you want to resume running DSNTIJNE, you do not need to make any change, just run the job again. Just execute the steps as defined and you can stop and start it as needed. Do not take long though to migrate your catalog, you will use the new functions only after completing migration and you do not want to keep your DB2 subsystems not aligned for too long. 358 DB2 UDB for z/OS Version 8 Performance Topics Migration V8 CM to V8 NFM CPU Time Elapsed Time 0 5 10 15 20 25 30 Gigabytes Catalog Size
Summary and recommendations Migration from V7 to V8 CM takes from 0.2 to 10 minutes depending on the size of the catalog and directory (medium to large). Before the catalog migration, it is recommended that you clean up your catalog doing a MODIFY on all table spaces: The result will be a cleanup on the SYSCOPY.SYSLGRNX entries. It is also useful to free the old version of packages that are not being used any more. Note: When you execute a MODIFY, do not forget to take a look at the tables that will be in copy pending, because your application might not be expecting the DB2 return code. Reorg Catalog and Directory before migrating to NFM. Migration from V8 CM to V8 NFM takes from 0.1 to 2 hours depending on the size of the catalog and directory (medium to large). The longest step is the catalog reorg DSNTIJNE, and the execution of that job can be divided. The size of the catalog, both data and index, has been observed to increase between 1% and 10%. Online REORG SHRLEVEL REFERENCE of SPT01 and 17 catalog tables is the most time-consuming component. A very rough Rule-of-Thumb on estimating the time for a medium to large catalog and directory in non-data sharing is: 6 min. + 3 to 7 min. per GB of SPT01, SYSPKAGE, SYSDBASE, etc. The time is heavily dependent on the DASD and channel model used. Allocate larger work files for online REORG of large tables such as SYSDBASE, SYSPKAGE. Allocate work files on separate DASDs, LCUs for online REORG of tables with parallel sort/build indexes such as SYSHIST, SYSPKAGE, SYSSTATS, and SPT01. 9.5 Catalog consistency query DSNTESQ The DSNTESQ sample job is provided to DB2 users so that they can check the consistency of their DB2 catalogs. This sample job consists of DDL, INSERT and 65 queries to verify the integrity of the catalogs and directories. The SQL can be run from SPUFI or DSNTEP2 and contains DDL which creates copies of the catalog using segmented table spaces. In some cases, the queries in DSNTESQ run faster when run on copies of the catalog instead of the actual catalog because the copies have additional indexes. Some of these catalog consistency queries can run for extended periods of time on subsystems with large amounts of catalog data. In order to improve the performance of most of these DSNTESQ catalog consistency queries, they were rewritten to use non correlated subqueries on table columns that are in index keys. In the past, some queries in DSNTESQ have had very poor performance. In DB2 V6, a customer introduced a subset of queries rewritten from DSNTESQ which performed very well against IBM supplied DSNTESQ queries. In DB2 V8, some queries from DSNTESQ were rewritten for performance and retrofitted to DB2 V7. On Table 9-7 we have an example of retrofitted queries followed by other rewritten queries. Table 9-5 Queries 5 and 18 rewritten for better performance Query (DB2 V8 - New Function Mode) Old (V8 NFM) New (V8 NFM) Chapter 9. Installation and migration 359
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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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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
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Page 384 and 385: dynamic statement cache. If activat
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Page 388 and 389: Table Number of rows SYSDATABASE 75
Page 392 and 393: Old - Query 5 New - Query 5 CPU (se
Page 394 and 395: Query 35 36 Old DSNTESQ CPU 1 hr 1
Page 396 and 397: 10.1 DB2 Estimator DB2 Estimator V8
Page 398 and 399: - REAL AND AUXILIARY STORAGE This i
Page 400 and 401: Another use is during back out of a
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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
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Page 438 and 439: PREDICATE ANALYSIS ----------------
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D.1 DB2 EXPLAIN EXPLAIN describes t
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Table D-2 PLAN_TABLE contents and b
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Column Type Content SORTC_ORDER BY
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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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DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

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