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Discover how to solve critical performance issues by understanding that high disk activity, slow I/O response and excessive application I/O requests are responsible. You'll also learn why these kinds of issues can't be solved by CPU upgrades.
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Improving Efficiency of I/O Bound Systems
Improving Efficiency of I/O Bound Systems
• More Memory, Better Caching• Newer and Faster Disk Drives• Set Object Access (SETOBJACC)
• Reorganize (RGZPFM) w/ Key File• Applications Requesting Less I/O
Validate That System Is Actually I/O Bound
Validate That System Is Actually I/O Bound
• CPU Is Under Utilized!• Poor Interactive Response Time• Long Running Batch Jobs• High Memory Faulting• High Disk Actuator Arm Activity
System Navigator
Identify Files With Highest Physical I/O
Identify Files With Highest Physical I/O
• Set Object Access (SETOBJACC)• Better Blocking of Data• Internal Program Arrays• Purge Old Transaction History• Build Better Logical Files• Stop Full Table Scans
Tune Database, Avoid Access Path Rebuilds
Tune Database, Avoid Access Path Rebuilds
• Identify Files Most Heavily Hit• Avoid SQL Full Table Scans• Limit Access Path Rebuilds• Small Tables OK, Large – Not!• Basic Database Administration• Dramatic Reduction in I/O Needs
Identify Specific Culprits & New Logicals
Identify Specific Culprits & New Logicals
• Batch, Interactive or ODBC• Specific Jobs and Users• Actual I/O by File and Program• Skipped Records v.s. Selected• New Permanent Logical Files• Delete Old Ones Not Being Used
Query Optimizer
Avoid Simple CL Programming Issues
Avoid Simple CL Programming Issues
• Never CPYF w/ SELECT/OMIT• Use OPNQRYF and CPYFRMQRYF• Easy Technique, Limit I/O Needs• Use RPG, COBOL, SQL, etc..• Prevent I/O From Full Table Scans• Work File in QTEMP w/ Keys
Prevent Unnecessary Opens and Closes
Prevent Unnecessary Opens and Closes
• Leave Files Open, Reuse Paths• Simply Move Record Pointer• Files Left Open All Day, GOOD!• Better Than Constant Opens/Closes• Share Open Data Paths Correctly• RETRN v.s SETON LR
Identify Specific Job and User Culprits
Identify Specific Job and User Culprits
• Focus on 80/20 Rule• Get Hardware & Software In Sync• Database Tuning• System Management Changes• Application Optimization Changes• Hardware Upgrades
Workload Navigator
Find Specific Operating System Functions
Find Specific Operating System Functions
• QQQIMPLE and QSQROUTE• QDBGETSQ v.s. QDBGETKY• Trace Back to Application Program• Simple Code Changes, No Rewrite• Weigh Cost v.s. Benefit• Find Quick, Easy Code Fixes
Analyze Application Program Efficiency
Analyze Application Program Efficiency
• 75% Finding Data, Inefficient!• Less Time Searching, Sorting• Free Up I/O Bottleneck• Allow CPU to be Used Effectively• Consume Resource w/ Updates• Process Only Selected Transactions
Identify Specific Database File I/O Counts
Identify Specific Database File I/O Counts
• Compare Reads to Writes/Updates• Less Time Reading via Indexes• Reduce I/O to Only Selected Records• Avoid Full Table Scans• Prevent Access Path Rebuilds• Use Proper Keyed File Sequences
Find Procedures within Code Causing Issues
Find Procedures within Code Causing Issues
• Rewrite Just Specific Procedure• Summarize Data More Efficiently• Use Pre-Summarized Data Tables• Avoid Constant Re-Processing• Extract Data Once, Reuse Many• Process Only “OPEN” Transactions
Q&A
To receive MB Software’s FREE performance evaluation:
1. Register at http://www.mb-software.com 2. Download and install software on AS/400 or iSeries 3. Call (800) 713-5034 to schedule your free performance review session
What To Expect:
After allowing performance data to accumulate for one full business day, you will log into a secure area of MB Software’s web site. We will then have a conference call to discuss our findings and how you can gain performance improvements with your existing applications. It’s that easy!
Questions & Answers
