Debugging/Tuning Queries via iSeries Navigator Tom McKinley

Tour Whats info is available –System Monitoring –Collection Services –Work Management –Table –Show Indexes –Index Advisor (DB, Schema or table level) BETA ONLY, removed from presentation. –Stats

System Level Monitoring

Example System Monitor

Open Monitor

Active Jobs

Current SQL For A Job

Current SQL for a job

Explain from Current SQL

Index Advised

Columns Stats on a table

Column Stats Details

Statistics Requests

Other sources of Info DB2 for iSeries Web Site – Monitor queries – White papers – SQL performance and query optimization guide (Info Center) Common, Tech Conferences… Query Performance tuning workshop – 03.ibm.com/servers/eserver/iseries/service/igs/db2performance.html

Summary Many things affect query plans Try to understand the access methods Learn the tools Size matters –Bad Performance does not scale. You need to collect info before you make changes to help understand what changed and the impact of that change. Dont only focus on Runtime. Look for resource hogs, or for queries that are run frequently Good indexing strategy in some cases is critical