Workload Qualification - Oracle Exadata Recipes: A Problem-Solution Approach - page 89

It does this by accepting a SQL Tuning Set and launching SQL Performance Analyzer with cell_simulation_
enabled = FALSE , then with cell_simulation_enabled = TRUE . At its completion, it compares the results of the SQL
Performance Analyzer executions. Specifically:

1. An administrator creates a SQL Tuning Set.

2. An administrator runs the Exadata Simulator using either tcellsim.sql or Enterprise

Manager.

3. SQL Performance Analyzer performs an initial analysis with Exadata cell simulation

disabled:

dbms_sqlpa.execute_analysis_task(
task_name => :aname,
execution_type => 'execute',
execution_name => 'cell_simulation_DISABLED',
execution_params => dbms_advisor.arglist('cell_simulation_enabled',
'FALSE'));

4. SQL Performance Analyzer then performs an analysis with cell simulation enabled:

dbms_sqlpa.execute_analysis_task(
task_name => :aname,
execution_type => 'execute',
execution_name => 'cell_simulation_ENABLED,
execution_params => dbms_advisor.arglist('cell_simulation_enabled',
'TRUE'));

5. When complete, performance results between the two tests are compared using the

IO_INTERCONNECT_BYTES metric:

dbms_sqlpa.execute_analysis_task(:aname, 'compare',
execution_params => dbms_advisor.arglist('comparison_metric',
'io_interconnect_bytes'));

6. Finally, the simulator displays output in a report:

select dbms_sqlpa.report_analysis_task(:aname, 'text', top_sql => 10) spa_summary

The Exadata Simulator is designed to analyze and capture the metrics from the most relevant Exadata Storage
Server metric, IO_INTERCONNECT_BYTES , based on logic built within SQL Performance Analyzer to estimate the savings
in I/O to be expected if/when the workload SQL statements run on an Exadata platform. The results give an indication
of the extent of the benefit you could possibly expect to get from a database workload port to Exadata. One of the nice
things about this simulation analysis is that it takes in to consideration your current , unmodified workload, without
application design change or SQL refactoring.

■ the results from exadata Simulation can provide a frame of reference for expected benefit on exadata,
but many other factors can also contribute to this analysis.

Note