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

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– SORT 6 indexes in parallel – CHECK 6 indexes in parallel time in seconds Figure 6-2 SHRLEVEL CHANGE vs. SHRLEVEL REFERENCE with FlashCopy SHRLEVEL CHANGE w/o FlashCopy vs. SHRLEVEL REFERENCE This test case measures the CPU and elapsed time comparing CHECK INDEX with option SHRLEVEL CHANGE without FlashCopy to CHECK INDEX with option SHRLEVEL REFERENCE. DFSMSdss does not find FlashCopy V2 enabled in the ESS and reverts to concurrent copy. In this case the elapsed time of SHRLEVEL CHANGE increases significantly. The results are shown in Figure 6-3. 266 DB2 UDB for z/OS Version 8 Performance Topics 900 800 700 600 500 400 300 200 100 0 Check Index SHRLEVEL CHANGE with FlashCopy versus SHRLEVEL REFERENCE PI (10 partitions) NPI 6 indexes CPU SHRLEVEL(REFERENCE) CPU SHRLEVEL(CHANGE) Elapsed time SHRLEVEL(REFERENCE) Elapsed time SHRLEVEL(CHANGE)
time in seconds 6.1.2 Conclusion 180 160 140 120 100 Figure 6-3 SHRLEVEL CHANGE vs. SHRLEVEL REFERENCE w/o FlashCopy Online CHECK INDEX (SHRLEVEL CHANGE) dramatically cuts down elapsed time. The first reason is that the parallel processing structure minimizes elapsed time in cross checking the data and indexes. The second reason is using FlashCopy V2. Compared to online CHECK INDEX with a non-partitioned index, online CHECK INDEX with a partitioned index could provide better performance. The most important aspect from the availability point of view is that using CHECK SHRLEVEL(CHANGE) with FlashCopy 2 the table and the indexes are available for RW after a few seconds, while with SHRLEVEL(REFERENCE) they are both in UTRO for most of execution time. Another study shows the better performance of CHECK INDEX with SHRLEVEL CHANGE in one task, when compared to CHECK INDEX with SHRLEVEL REFERENCE as concurrent jobs of each table space partition. It means you should always choose SHRLEVEL CHANGE for shorter CPU and elapsed time, rather than SHRLEVEL REFERENCE, when FlashCopy V2 is available. The two options have a different behavior: ► SHRLEVEL REFERENCE Unload phase unloads keys from the indexes and then the Check phase compares sorted keys against the data via tablespace scan. ► SHRLEVEL CHANGE Unload phase does a tablespace scan extracting keys and then the Check phase compares sorted keys against the keys in the index. 6.1.3 Recommendations 80 60 40 20 0 Check Index SHRLEVEL CHANGE versus SHRLEVEL REFERENCE no FlashCopy PI NPI CPU SHRLEVEL(REFERENCE) CPU SHRLEVEL(CHANGE) Elapsed time SHRLEVEL(REFERENCE) Elapsed time SHRLEVEL(CHANGE) Use online CHECK INDEX whenever availability is needed. You should use online CHECK INDEX in conjunction with FlashCopy V2, otherwise concurrent copy is invoked which increases elapsed time and elongates the time when the data and index are read-only. To Chapter 6. Utilities 267
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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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--------------------------- -------
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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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Page 250 and 251: 5.1 System level point-in-time reco
Page 252 and 253: BACKUP SYSTEM During backup DB2 rec
Page 254 and 255: Figure 5-1 FRBACKUP PREPARE elapsed
Page 256 and 257: Figure 5-4 BACKUP SYSTEM FULL measu
Page 258 and 259: 5.1.2 Conclusion The BACKUP SYSTEM
Page 260 and 261: 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
Page 266 and 267: ► CHAR(8) to VARCHAR(8) ► CHAR(
Page 268 and 269: Before ALTER INDEX add column, a ta
Page 270 and 271: 30 25 20 15 10 Figure 5-12 FETCH CP
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
Page 282 and 283: Load table of 20M rows, 10 partitio
Page 284 and 285: Times in seconds 20 18 16 14 12 10
Page 286 and 287: RUNSTATS INDEX PARTITION of a DPSI
Page 288 and 289: Note that when the qualified partit
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Page 292 and 293: 5.6.10 Support for more than 245 se
Page 294 and 295: 6.1 Online CHECK INDEX Online CHECK
Page 296 and 297: SORTOUT DD UNIT=SYSDA,SPACE=(CYL,(5
Page 300 and 301: make DB2 take the maximum paralleli
Page 302 and 303: 6.3 LOAD and UNLOAD delimited input
Page 304 and 305: 6.3.2 Conclusion We measured the CP
Page 306 and 307: Options for cardinality and distrib
Page 308 and 309: ► Number of column groups: 1 ►
Page 310 and 311: cases is the total time of RUNSTATS
Page 312 and 313: 6.4.5 Conclusion Statistics Advisor
Page 314 and 315: goals for end-user services. We sho
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Page 322 and 323: 7.2.2 Performance - Distributed cli
Page 324 and 325: Recommendation If you currently do
Page 326 and 327: ► The DB2 Universal JDBC type 4 D
Page 328 and 329: WebSphere z/OS - DB2 z/OS V8 - Serv
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Page 332 and 333: Use DB2 Connect when a high amount
Page 334 and 335: JCC Type 4 Direct 4:3 Concentration
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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7.6.3 Performance The following inf
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Impact on coupling facility: You do
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Table 8-1 shows extracts from DB2 P
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and secondary GBP structures have t
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DB2 member already has the table sp
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8.2.1 Performance We ran a number o
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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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DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

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