11g nf sql_anlz
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This document discusses SQL Performance Analyzer and how it can be used to forecast the impact of potential database changes on the performance of SQL queries. It extracts a SQL Tuning Set (STS) from production, transports it to a test system, re-executes the SQL after applying changes, detects any performance improvements, regressions or plan changes, and allows tuning of regressed SQL queries.
11g nf sql_anlz
- 2. SQL Performance Analyzer forecast the impact of a potential change on the performance of a SQL query workload.WHEN?• Database upgrades• Implementation of tuning recommendations• Schema changes• Statistics gathering• Database parameter changes• OS/hardware changes might be reported for as a Tuning Result
- 3. SQL Performance AnalyzerExtract STS(SQL Tuning Set) from productionWhat’s inside?FROM Cursor Cache– SQL Text– Bind variables– Execution plans– Execution statistics- Incremental capture over a time period- filtering and ranking capabilities filters out undesirable SQLFILTERINGAlways all? No!
- 4. SQL Performance AnalyzerTransport to a test system (STS COPY)변 경 전변 경 후ExecuteRe-Execute• Test-Execute SQL– produce execution plans and statistics– execute SQL serially– every SQL is executed only once• Explain plan SQL in SQL tuning set to generate SQL plans onlySQL Performance = execution plans + execution statistics
- 5. SQL Performance AnalyzerAnd nextDetect - improvements - regressions - unchanged performance - changes in execution plansTune - regressed SQLs - indexChoose - SQL Plan Management baselineXO?SQL Performance = execution plans + execution statistics
- 6. SQL Performance AnalyzerDoCreating a SQL Tuning Set (Capturing the SQL Workload) Sources - Cursor Cache - AWR Snapshots, Baselines - User-defined Workload (sql_text, parsing_schema_name columns)Exporting the SQL Workload - choose to export the selected STS - load a STS on the test system for comparison purposesCollect SQL PerformanceChange - parameter - index - hintSQL Performance = execution plans + execution statistics
- 7. SQL Performance AnalyzerDo DoCollect SQL PerformanceCompare SQL PerformanceAnalysis Results - before vs afterUsing EMSQL Performance = execution plans + execution statistics
- 8. SQL Performance AnalyzerDo DoDoDBMS_SQLTUNE - CREATE_TUNING_TASK - EXECUTE_TUNING_TASK - REPORT_TUNING_TASK - etc………………To be continued………………SQL Performance = execution plans + execution statistics