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

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time Figure 10-1 DB2 HPU vs. UNLOAD utility Case 1 through Case 5 Figure 10-2 shows Case 6 through Parallel. time 70 60 50 40 30 20 10 Figure 10-2 DB2 HPU vs. UNLOAD utility Case 6 through Parallel HPU and DSNTIAUL We show two sets of measurements, one with DSNTIAUL not using multi-row fetch, and another one using multi-row fetch. Note that DSNTIAUL in V8 always uses multi-row fetch. 374 DB2 UDB for z/OS Version 8 Performance Topics 0 70 60 50 40 30 20 10 0 DB2 HPU vs. UNLOAD HPU CPU UNLOAD CPU HPU ET UNLOAD ET Case 1 Case 2 Case 3 Case 4 Case 5 DB2 HPU vs. UNLOAD HPU CPU UNLOAD CPU HPU ET UNLOAD ET Case 6 Case 7 Case 8 Case 9 Case 10 Parallel
DSNTIAUL without multi-row fetch The results of the performance measurement between HPU and DB2 V8 DSNTIAUL are summarized in Table 10-6 for the case where DSNTIAUL is not using multi-row fetch. Table 10-6 HPU V2.2 vs. DB2 V8 DSNTIAUL (no multi-row) Test case HPU V2.2 DB2 V8 DSNTIAUL % Difference CPU Elapsed CPU Elapsed CPU Elapsed Case 1 11.89 62 186.99 239 1472.66 285.48 Case 2 9.44 61 N/A N/A N/A N/A Case 3 13.57 59 186.77 238 1276.34 303.38 Case 4 9.67 46 148.46 166 1435.26 260.86 Case 5 18.00 58 184.71 236 926.16 306.89 Case 6 13.93 46 146.33 163 950.46 254.34 Case 7 12.87 45 8.23 45 -36.05 0 Case 8 17.80 59 191.34 237 974.94 301.69 Case 9 12.51 45 1.75 22 -86.01 -51.11 Case 10 2.39 22 1.75 22 -26.77 0 Parallel 15.33 24 N/A N/A N/A N/A DSNTIAUL can use an index so one would assume that DSNTIAUL may have a slight advantage over the UNLOAD utility. However, the measurement cases illustrate otherwise. DSNTIAUL was the larger consumer of CPU time and also typically had the longer elapsed time, although two test cases showed DSNTIAUL being the better performer. However, when you compare DSNTIAUL with HPU, the results are extraordinary. HPU outperformed DSNTIAUL by using less than 10% of the CPU time. Nearly every unload product is written with the assumption that users will unload a large percentage of the available data, usually in the 50 - 100% range. In these instances, it may be better to scan the entire table rather than using an index. However, there are times when you may want to unload a small percentage of the rows, perhaps 10 - 20% and you know an index exists that allows access to the table data. In this case, a scan of the table may result in worse performance than if an SQL statement were executed directly by DB2; you may then see better performance with DSNTIAUL than with HPU. If you are using HPU and you have a query where using the SQL might perform better than a table space scan, use the DB2 FORCE parameter. This causes HPU to pass the query to DB2 for execution and may result in better performance. This is evident in case 10 which is the same as case 9 except DB2 FORCE is used. The results are once again dramatic; there is a 6X improvement in CPU time with the exact same elapsed time. Note: DSNTIAUL cannot unload from an image copy data set so the results are N/A for case 2. Chapter 10. Performance tools 375
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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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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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A second role of the managed server
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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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Page 372 and 373: 340 DB2 UDB for z/OS Version 8 Perf
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 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
Page 402 and 403: In DB2, the IBM Data Encryption too
Page 404 and 405: The utilities ran on a G7 Turbo wit
Page 408 and 409: DSNTIAUL with multi-row fetch The r
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
Page 444 and 445: Column Type Content SORTC_ORDER BY
Page 446 and 447: Column Type Content OPTHINT CHAR(8)
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Page 450 and 451: Example: D-1 Creating DSN_STATEMENT
Page 452 and 453: 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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