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

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6.4.5 Conclusion Statistics Advisor tool This tool is a function of the new Visual Explain and it can help you cut down the effort in determining what kind of distribution statistics you need to run and set up the RUNSTATS control statements. For information about the Statistics Advisor tool refer to 3.15.3, “Statistics Advisor” on page 116. V8 RUNSTATS with distribution statistics achieves a better performance compared to V7 RUNSTATS and the DSTATS tool. You no longer need to run the separate DSTATS program to collect distribution statistics, in V8 RUNSTATS will do it and cut down CPU and elapsed time. Measurements show that increasing the number of columns or column groups to collect statistics may significantly impact CPU and elapsed time. However, access path improvements provided by distribution statistics can be quite remarkable. 6.4.6 Recommendations 6.5 Cross Loader To get good performance when using RUNSTATS distribution statistics in V8, it is important to be current with maintenance, apply the fixes for PQ90884 and PQ94147 (dynamic prepare). We also recommend you use the Statistics Advisor tool to define the right statistics for your application: The Statistics Advisor suggests what RUNSTATS and DSTATS are needed for your queries. The CPU overhead observed when there are hundreds of frequency values in SYSCOLDIST can be reduced by deleting unnecessary information from the catalog table. The Cross Loader function enables you to use a single LOAD job to transfer data from one location to another location or from one table to another table at the same location. You can use either a local server or any DRDA-compliant remote server as a data input source for populating your tables. Your input can even come from other sources besides DB2; you can use IBM Information Integrator for access to data from other relational or non-relational data sources. For more information abut the cross loader function of the LOAD utility, see DB2 UDB for z/OS Version 8 Utility Guide and Reference, SC18-7427. 6.5.1 Performance APAR APAR PQ84160, opened on V7, has optimized the code reducing the path length by a large percentage. Prior to this fix, the cross loader took longer than the normal LOAD and UNLOAD utilities. With two times performance improvement provided by this rework, the cross loader is now at the same level as LOAD and UNLOAD in terms of performance. PTFs are available for both V7 and V8: ► V7: UQ91416 ► V8: UQ91422 280 DB2 UDB for z/OS Version 8 Performance Topics
Chapter 7. Networking and e-business 7 This chapter describes enhancements related to distributed processing and e-business applications. ► DDF enhancements: A requester database alias, a server location alias and member routing in a TCP/IP network are provided in DDF. The DRDA architecture allows larger query blocks: the number of network exchanges between the workstation and a DB2 for z/OS V8 server is about half that when accessing the DB2 for z/OS V7 server. ► Multi-row FETCH and INSERT in DRDA: Multi-row FETCH and INSERT have a significant positive impact on performance in a DRDA client/server environment. However, that performance impact differs when DB2 for z/OS V8 acting as a DRDA application server is being accessed from a DB2 Connect Client running on Linux, Unix and Windows or another DB2 for z/OS V8 acting as a DRDA application requester. ► WebSphere and DB2 Universal Driver for SQLJ and JDBC: In the past, access to a Linux, UNIX and Windows server and a z/OS server used different database connection protocols. To provide transparent access across the DB2 Family, these protocols are now standardized, and all of them use the Open Group’s DRDA Version 3 standard. This new architecture is called the Universal Driver. The first deliverable of this new architecture is the IBM DB2 Universal Driver for SQLJ and JDBC Version 1.0, also known as the IBM Java Common Connectivity. ► ODBC enhancements: Several DB2 ODBC enhancements such as Unicode support, improved authentication, long name support, 2 MB SQL statements and SQLcancel are briefly presented in this section. ► XML support in DB2 for z/OS: In DB2 V7, you could use the XML extender feature for manipulating XML data in and out of DB2. The SQL/XML Publishing Functions become available in DB2 V8 and provide a set of SQL built-in functions that allow applications to generate XML data from relational data with high performance. It reduces application development efforts in generating XML data for data integration, information exchange, and web services, thus enhancing the leadership position of DB2 for z/OS as the enterprise database server. This is the first step DB2 for z/OS takes to more tightly integrate XML into the database engine. ► Enterprise Workload Manager: Enterprise Workload Manager (EWLM) enables you to automatically monitor and manage multi-tiered, distributed, heterogeneous or homogeneous workloads across an IT infrastructure to better achieve defined business © Copyright IBM Corp. 2005. All rights reserved. 281
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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
Page 262 and 263: Maybe you have implemented a space
Page 264 and 265: For dynamically prepared queries, D
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Page 268 and 269: Before ALTER INDEX add column, a ta
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Page 272 and 273: Percent of index pages Avg. Index L
Page 274 and 275: 300 250 200 time in seconds 150 100
Page 276 and 277: REORG REBALANCE We executed and mea
Page 278 and 279: 5.4 Volatile table 5.4.1 Conclusion
Page 280 and 281: If explicit clustering for a table
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Page 286 and 287: RUNSTATS INDEX PARTITION of a DPSI
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Page 292 and 293: 5.6.10 Support for more than 245 se
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Page 298 and 299: - SORT 6 indexes in parallel - CHEC
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Page 302 and 303: 6.3 LOAD and UNLOAD delimited input
Page 304 and 305: 6.3.2 Conclusion We measured the CP
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Page 324 and 325: Recommendation If you currently do
Page 326 and 327: ► The DB2 Universal JDBC type 4 D
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Page 332 and 333: Use DB2 Connect when a high amount
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Page 336 and 337: The SYSIBM.INDOUBT table and the pa
Page 338 and 339: Batch updates A batched update is a
Page 340 and 341: Example In DB2 V8 SQL/XML publishin
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Page 344 and 345: 7.5.3 Conclusion The new XML publis
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esolve any contention. This extra a
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There is also no need to use RELEAS
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Table 8-12 DB2 I/O CI Limit Removal
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8.5 Miscellaneous items In this sec
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DB2 V8 improves Restart Light. If i
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9.1 Unicode catalog DB2 for z/OS su
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that all applications are converted
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- CLASST: Specifies the threshold a
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From these measurements we observe
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Class 1 CPU time (MSEC) 200 150 100
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dynamic statement cache. If activat
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that everything is ready. This step
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Table Number of rows SYSDATABASE 75
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In Figure 9-7 we describe the perfo
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Old - Query 5 New - Query 5 CPU (se
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Query 35 36 Old DSNTESQ CPU 1 hr 1
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10.1 DB2 Estimator DB2 Estimator V8
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- REAL AND AUXILIARY STORAGE This i
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Another use is during back out of a
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In DB2, the IBM Data Encryption too
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The utilities ran on a G7 Turbo wit
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time Figure 10-1 DB2 HPU vs. UNLOAD
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DSNTIAUL with multi-row fetch The r
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A.1 Maintenance for DB2 V8 The APAR
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APAR # Area Text PTF and Notes PQ88
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APAR # Area Text PTF and Notes PK21
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B.1 DB2 PE Storage Statistics trace
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Storage heading Description 24 BIT
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C.1 DB2 SQL PA additional reports N
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|is the last matching predicate. Ap
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|ANL6052I *** NOTE: | |This index i
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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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