DB2 Performance & Tuning with iStrobe

Frank Schuler

Strobe MF Application Performance Management Field Technical Support

September 20, 2012

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DB2 Performance & Tuning with iStrobe

1. Strobe & iStrobe 2. CICS Case Study 3. Batch Case Study 4. DB2 / DDF Case Study 5. Consider DB2 System Services

The Strobe Process

MeasuringMeasuring

Sample Dataset

ReportingReporting

Add Request Pgm Execution

StrobeMeasurement Strobe

Reporter

Strobe Profile

iStrobe

CPU

I/O

STROBE drills down through all the layers of your OS/390 address space to pinpoint specific areas of resource demand

Data sets

I/O Devices

I/O Subsystems

Database Management Systems

OS/390 Operating System

Database & IO Subsystems

CICS

Library Routines

UserPrograms

What Strobe Sees

CPU

I/O

STROBE drills down through all the layers of your OS/390 address space to pinpoint specific areas of resource demand

Data sets

I/O Devices

I/O Subsystems

Database Management Systems

OS/390 Operating System

Database and IO Subsystems

CICS

Library Routines

UserPrograms

What Strobe Sees

Analysis - iStrobe

• Browser-based product for• Navigating performance reports• Analyzing and improving performance

• Supplies tips for improving performance• Module HELP database supplies descriptions and

performance hints for system services• SQL Analysis Feature makes recommendations for

improving SQL performance

• iStrobe improves Strobe ease of use by providing a GUI home page look and feel for interpreting profile reporting

• Look for the biggest number or the longest line

• “Click until you click no more” (+ expands on current page)

• Jump to next report via ( Report Icon)

• 5 clicks or less to the root cause

iStrobe Automates the Strobe Profile Report Interpretation Process

Traditional Strobe Text Based Reports

iStrobe Automates Strobe Interpretation and Analysis

iStrobe – Initial Panel

CICS Case Study

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iStrobe 4.2 – Measurement Session Data - CICS

iStrobe 4.2 – Program CPU Usage

CA Detector

iStrobe 4.2 – DB2 Activity by Query

iStrobe 4.2 – SQL Analysis

iStrobe 4.2 – DB2 Explain Expanded

iStrobe 4.2 – DB2 Catalog Statistics

Analysis Summary•XIE1RULE: 206K Rows / 5.1K Pages

•XPKCLM_Rule(1) 277K Rows / 3.2K Pages

•Non-Matching Index Scan•Consider adding an index to Table ITS.RULE to change the Non-Matching Index Scan to a Matching Index Only Scan as follows:

• Column 1 – PRFX_CD• 2 – STS_QUAL_CD• 3 – STS_CD• 4 – LOC_PLAN_CD• 5 – PLAN_PROFL_UID

•Get Pages & CPU reduced

Batch

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iStrobe 4.2 – Measurement Session Data - Batch

iStrobe 4.2 – Program CPU Usage

CA Detector

iStrobe 4.2 – DB2 Activity by Query

iStrobe 4.2 – DB2 Explain

iStrobe 4.2 – DB2 Catalog Statistics

Analysis Summary

•ACSIS.OPEN: 259K Rows / 5.5K Pages

•There are 259,000 rows on this table but the cursor is opened nearly 5 million times. Resulting in a large number of duplicates.

•Recommend checking programmatically to see if the program will be accessing the same row(s) and not make the open again.

•Table ACSIS.OPEN. PCTROWCOMP is 0.0

• Consider turning DB2 Compression on if the NPAGES is greater than 500 and the DB2 compression utility DSN1COMP indicates the compression ratio would be greater than 30%

DDF

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iStrobe 4.2 – Measurement Session Data - DDF

iStrobe 4.2 – DB2 Stored Procedure SQL Activity

iStrobe 4.2 – DB2 Explain

iStrobe 4.2 – DB2 Catalog Statistics

Analysis Summary•XI18S1 6.5M Rows / 303K Pg

•Non-Matching Index Scan•Consider adding an index to Table TXT18S_BILL_VALIDATION to change the Non-Matching Index Scan to a Matching Index Only Scan as follows:

•Column 1 – ACCOUNT_ID• 2 – CIRCUIT_ID• 3 – PON• 4 – USOC• 5 – JURISDICTION_CD• 6 – BILL_DATE •

•Get Pages & CPU reduced

Consider what DB2 System Services is

doing on behalf of your SQL as part of your

analysis

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DB2Data

Relational Data System(RDS)Relational Data System(RDS)

• Checks SQL statements• Processes Stage 2 predicates• Performs sort and optimization

• Checks SQL statements• Processes Stage 2 predicates• Performs sort and optimization

Data Manager(DM)Data Manager(DM)

• Processes Stage 1 predicates• Processes indexable predicates• Interfaces with IRLM

• Processes Stage 1 predicates• Processes indexable predicates• Interfaces with IRLM

Buffer Manager(BM)Buffer Manager(BM)

• Manages bufferpools• Moves data to and from DASD• Manages bufferpools• Moves data to and from DASD

Database Services Address Space

DB2 Address Space Reporting #PUP ** PROGRAM USAGE BY PROCEDURE **

.SYSTEM SYSTEM SERVICES .DB2 DB2 SYSTEM SERVICES MODULE SECTION FUNCTION % CPU TIME MARGIN OF ERROR 6.84% NAME NAME SOLO TOTAL 00 8.00 16.00 DSNBBM DSNB1GET RETRIEVE REQUESTED PAGE 3.41 3.41 ***** DSNBBM DSNB1REL PAGE RELEASE ROUTINE .49 .49 * DSNECP10 DSNAPRH PGM REQUEST APPL INTERF 1.46 1.46 ** DSNECP10 DSNECP21 PARSE DSN COMMAND .49 .49 * DSNGEDM DATA MGT DBD/SKCT RTNS .49 .49 * DSNIDM DSNICSMP CHK MAP PAGE CONSISTENC .49 .49 * DSNIDM DSNICUBD ADD AN OBJECT TO CUB DY .49 .49 * DSNIDM DSNIMSAR RELEASE ALL MSA RESOURC 1.46 1.46 ** DSNIDM DSNINXTP READ SPECFD PAG USNG MS .49 .49 * DSNIDM DSNIOST2 SET ON CUB DEF ON IX FA .98 .98 ** DSNIDM DSNIPSBL LOC AN EXISTING PSCB .49 .49 * DSNIDM DSNIRNXT FETCH NEXT ROW TO PROG 14.15 14.15 ****************** DSNIDM DSNIRPRV TABLE SPACE SCAN BACKWA .49 .49 * DSNXGRDS RDS ACCESS MODULE GENER .32 .32(subsequent lines omitted)

Strobe will identify the DB2 services utilized by the SQL

DB2 Address Space Reporting #PUP ** PROGRAM USAGE BY PROCEDURE **

.SYSTEM SYSTEM SERVICES .DB2 DB2 SYSTEM SERVICES MODULE SECTION FUNCTION % CPU TIME MARGIN OF ERROR 6.84% NAME NAME SOLO TOTAL 00 8.00 16.00 DSNBBM DSNB1GET RETRIEVE REQUESTED PAGE 3.41 3.41 ***** DSNBBM DSNB1REL PAGE RELEASE ROUTINE .49 .49 * DSNECP10 DSNAPRH PGM REQUEST APPL INTERF 1.46 1.46 ** DSNECP10 DSNECP21 PARSE DSN COMMAND .49 .49 * DSNGEDM DATA MGT DBD/SKCT RTNS .49 .49 * DSNIDM DSNICSMP CHK MAP PAGE CONSISTENC .49 .49 * DSNIDM DSNICUBD ADD AN OBJECT TO CUB DY .49 .49 * DSNIDM DSNIMSAR RELEASE ALL MSA RESOURC 1.46 1.46 ** DSNIDM DSNINXTP READ SPECFD PAG USNG MS .49 .49 * DSNIDM DSNIOST2 SET ON CUB DEF ON IX FA .98 .98 ** DSNIDM DSNIPSBL LOC AN EXISTING PSCB .49 .49 * DSNIDM DSNIRNXT FETCH NEXT ROW TO PROG 14.15 14.15 ****************** DSNIDM DSNIRPRV TABLE SPACE SCAN BACKWA .49 .49 * DSNXGRDS RDS ACCESS MODULE GENER .32 .32(subsequent lines omitted)

Strobe will identify the DB2 services utilized by the SQL

Thank You