Beginning Oracle Database 11g Administration From Novice to Professional

CHAPTER 10 MONITORING 213
Monitoring Performance
Be sure to monitor the performance of important queries. The view records
execution statistics such as executions, CPU time, elapsed time, logical reads, and physical
reads for each SQL statement cached in the library cache—it is therefore a source of
workload information as well as performance information. Snapshots of the information in
the view are available in the table (in the case of STATSPACK)
and in the view (in the case of AWR). The SQL statement in Listing 10-10
retrieves the average execution times of each of two SQL queries of choice in successive
time periods; the query can easily be modified to include additional queries that are critical
to application performance. Notice the use of the analytic function to interpolate
missing values.
Listing 10-10. SQL Query to List the Average Elapsed Times for Two SQL Queries of Choice