Skip Headers

Oracle® Database Reference 10g Release 2 (10.2) Part Number B14237-02 |
Home | Book List | Contents | Index | Master Index | Feedback

Previous | Next
| View PDF

# STATISTICS_LEVEL

Property | Description
--- | ---
Parameter type | String
Syntax | `STATISTICS_LEVEL = { ALL | TYPICAL | BASIC }`
Default value | `TYPICAL`
Modifiable | `ALTER SESSION`, `ALTER SYSTEM`

`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

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 system-wide state is not changed:

- Timed statistics

- Timed OS 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".