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.
When the 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.
Setting the 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 (V$CLIENT_STATS
)
Database time distribution statistics (V$SESS_TIME_MODEL
and V$SYS_TIME_MODEL
)
Service level statistics
Buffer cache advisory
MTTR advisory
Shared pool sizing advisory
Segment level statistics
PGA Target advisory
Timed statistics
Monitoring of statistics