STATISTICS_LEVEL specifies the level of collection for database and operating system statistics. The Oracle Database collects these statistics for a variety of purposes, including making self-management decisions.
The default setting of
TYPICAL ensures collection of all major statistics required for database self-management functionality and provides best overall performance. The default value should be adequate for most environments.
STATISTICS_LEVEL parameter is set to
ALL, additional statistics are added to the set of statistics collected with the
TYPICAL setting. The additional statistics are timed OS statistics and plan execution statistics.
STATISTICS_LEVEL parameter to
BASIC disables the collection of many of the important statistics required by Oracle Database features and functionality, including:
Automatic Workload Repository (AWR) Snapshots
Automatic Database Diagnostic Monitor (ADDM)
All server-generated alerts
Automatic SGA Memory Management
Automatic optimizer statistics collection
Object level statistics
End to End Application Tracing (
Database time distribution statistics (
Service level statistics
Buffer cache advisory
Shared pool sizing advisory
Segment level statistics
PGA Target advisory
Monitoring of statistics
Note:Oracle strongly recommends that you do not disable these important features and functionality.
STATISTICS_LEVEL parameter is modified by
ALTER SYSTEM, all advisories or statistics are dynamically turned on or off, depending on the new value of
STATISTICS_LEVEL. When modified by
ALTER SESSION, the following advisories or statistics are turned on or off in the local session only. Their system-wide state is not changed:
Timed OS statistics
Plan execution statistics
V$STATISTICS_LEVEL view displays information about the status of the statistics or advisories controlled by the
STATISTICS_LEVEL parameter. See "V$STATISTICS_LEVEL".