What improvements are included in the Enhanced Wait Model introduced in Oracle 10g to facilitate proactive performance diagnosis?
The Enhanced Wait Model introduced in Oracle 10g is a core building block for many of the performance management features introduced in this release. Below is a brief list of the important stats improvements in the performance area: — Wait events are classified into wait classes (see the v$event_name) — v$active_session_history view provides a sampled history of active sessions in the system. — v$sys_time_model and v$sess_time_model views divide up database time in a different manner as compared to the wait model. — v$sql view contains additional columns that give the time spent by the SQL statement in the wait classes as well as in the PL/SQL and java interpreters. — v$sys_metrics view provides rates for a bunch of statistics based on 3 fixed time intervals (e.g., “logins/sec” for the last 15sec, 1min, etc.) In Oracle 10g stats are persisted onto disk automatically, this repository is called “Automatic Workload Repository”. Automatic performance diagnosis is now done in the datab
