2.390 STATISTICS_LEVEL
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.
Property | Description |
---|---|
Parameter type |
String |
Syntax |
|
Default value |
|
Modifiable |
|
Modifiable in a PDB |
Yes |
Basic |
No |
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 operating system 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:
-
All server-generated alerts
-
Automatic Database Diagnostic Monitor (ADDM)
-
Automatic optimizer statistics collection
-
Automatic SGA Memory Management
-
Automatic Workload Repository (AWR) Snapshots
-
Buffer cache advisory
-
Database time distribution statistics (
V$SESS_TIME_MODEL
andV$SYS_TIME_MODEL
) -
End to End Application Tracing (
V$CLIENT_STATS
) -
Monitoring of statistics
-
MTTR advisory
-
Object Activity Tracking System (OATS)
-
Object level statistics
-
PGA Target advisory
-
Segment level statistics
-
Service level statistics
-
Shared pool sizing advisory
-
Timed statistics
Note:
Oracle strongly recommends that you do not disable these important features and functionality.
When the STATISTICS_LEVEL
parameter is modified by ALTER SYSTEM
, all advisories or statistics are dynamically turned on or off, depending on the new value of STATISTICS_LEVEL
. When modified by ALTER SESSION
, the following advisories or statistics are turned on or off in the local session only. Their systemwide state is not changed:
-
Timed statistics
-
Timed operating system statistics
-
Plan execution statistics
The V$STATISTICS_LEVEL
view displays information about the status of the statistics or advisories controlled by the STATISTICS_LEVEL
parameter. See "V$STATISTICS_LEVEL".
See Also:
Oracle Database Performance Tuning Guide for more information about this parameter