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

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Table 4-4 System storage configuration DB2 V7 vs. DB2 V8 DB2 V7 uses a data space for the dynamic statement cache. In addition, there is a negligible use of the Sort pool, RID pool, and global dynamic statement cache in the EDM pool (less than 1 MB). The parameter KEEPDYNAMIC was set to NO so there is no local dynamic statement cache. Here are the different types of workloads we examined to understand the impact of static vs. dynamic SQL: ► Dynamic SQL using CLI and OBDC on AIX, connecting to DB2 Connect and using DRDA to communicate with DB2. ► Dynamic SQL using the DB2 Universal Driver Type 4 on AIX, connecting to DB2 Connect and using DRDA to communicate with DB2. ► Static SQL embedded in a local application running on AIX, connecting to DB2 Connect and using DRDA to communicate with DB2. ► Static SQL using the DB2 Universal Driver Type 4 on AIX, using DRDA to directly connect to DB2. ► A local IRWW OLTP workload directly connecting to DB2 using IMS attach. ► A local IRWW OLTP workload directly connecting to a two member data sharing group running DB2 using IMS attach. During the performance tests, RMF storage statistics were gathered as well as DB2 storage statistics using IFCID 225. In order to validate the storage statistics reported by DB2 PE, and storage information collected from the RMF monitor reports, system dumps were taken of all DB2 address spaces. In addition, SDSF DA (Display Active) real storage usage was captured. As a result, we were able to compare the difference between DB2 V7 and V8 DBM1 and DIST virtual and real storage per DBAT and active connection. The results are presented here. Remember that your results may be very different as most customer workloads do not resemble this configuration; usually customers have a mix of different applications all running in a single DB2 subsystem. Take this into consideration as you examine the potential impact of your migration to DB2 V8. Virtual and real storage comparison for DBM1 We first look at virtual storage used by the DBM1 address space. Figure 4-4 compares the total virtual storage usage for the DBM1 address space for all of these different workloads with DB2 V7 vs. V8. However, to be fair, the virtual buffer pools were removed from the equation; you can see that GETMAINed storage is represented by GM - BP in the graph where the storage for these buffer pools were removed. A significant decrease in storage below the 2 GB bar is possible. With V8, several DBM1 address space structures that consume large amounts of storage below the bar, have moved 148 DB2 UDB for z/OS Version 8 Performance Topics DB2 V7 DB2 V8 BP type Primary (MB) Above 2 GB bar (MB) 4 KB BPs 438 438 8 KB BPs 16 16 KB BPs 16 EDM pool 146 146
to above the bar, for example, buffer pools, compression dictionaries, DBDs in the EDM pool and some Sort pool and RID list storage. These all come from GETMAINed storage. The GETMAINed storage after the virtual buffer pools are subtracted in DB2 V7 does not change significantly. The predominant storage areas that increase as you migrate from V7 to V8 in all cases are stack and variable storage. This is primarily thread-related storage which must be larger to support new V8 functionality such as long names, Unicode support and some 64-bit addressing requirements. In addition, in V8 the RDS OP Pool used during bind has been replaced by thread variable storage. Getmained area is shown as constant for all distributed workloads, but in reality V8 is smaller. The problem is that virtual pool size is artificially subtracted without accounting for an overhead associated with data space buffer pool, such as lookaside buffer and data space buffer control blocks. KB 450000 400000 350000 300000 250000 200000 150000 100000 50000 0 DBM1 below 2 GB Virtual Storage Comparison V7 CLI V8 CLI Figure 4-4 DBM1 below 2 GB virtual storage comparison for different workloads Non-distributed performance Here we report on the IRWW workload for a non-distributed environment comparing the DBM1 virtual storage consumption for the different main virtual storage areas in V7 and V8 for a non-data sharing environment and a data sharing environment. Table 4-5 Non-distributed DBM1 virtual storage comparison V7 JDBC V8 JDBC V7 EMB V8 EMB V7 SQLJ V8 SQLJ V7 IRWW V8 IRWW V7 IRWW DSHR V8 IRWW DHSR V7 IRWW V8 IRWW % change V7 IRWW V8 IRWW % change Non-data sharing Data sharing GM - BP 33075 21146 -36% 50248 22830 -55% Variable 47565 71967 51% 38738 33669 -13% Stack Fixed Variable GM-BP Fixed 102 328 322% 87 195 124% Chapter 4. DB2 subsystem performance 149
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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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Page 138 and 139: 3.12.5 Conclusion Multi-row FETCH a
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Page 142 and 143: 3.14.2 Conclusion Percent reduction
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Page 160 and 161: ► Larger VSAM CI sizes: DB2 V8 in
Page 162 and 163: 4.1.1 Performance support caused al
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Page 166 and 167: The results indicate no significant
Page 168 and 169: Important: 4.1.2 Conclusion If you
Page 170 and 171: However, the combined impact of oth
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Page 184 and 185: KB 600 500 400 300 200 100 0 Figure
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Page 188 and 189: 4.2.3 Conclusion Nondistributed per
Page 190 and 191: Important: With PTFs UK04394 (DB2 V
Page 192 and 193: - DATASPACE BP CONTROL BLOCKS = 0 M
Page 194 and 195: The EXTENDED REGION SIZE (MAX) is t
Page 196 and 197: RDS OP POOL (MB) N/A RID POOL (MB)
Page 198 and 199: As you can now appreciate, it is im
Page 200 and 201: Megabytes A V7 Customer DBM1 Thread
Page 202 and 203: 4.5.1 Performance The most buffer p
Page 204 and 205: 4.6.1 Performance maintained in a 2
Page 206 and 207: 4.6.2 Conclusion We can conclude th
Page 208 and 209: service for Unicode conversions, an
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Page 216 and 217: 4.7.1 Performance The improvements
Page 218 and 219: In October 2003, a new enhancement
Page 220 and 221: UseServerEncoding data source prope
Page 222 and 223: 4.8.1 Performance 4.8.2 Conclusion
Page 224 and 225: Multilevel security with row-level
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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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216 DB2 UDB for z/OS Version 8 Perf
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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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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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