To implement Automatic Memory Management (AMM), you set the following parameters:
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When you try to start the database instance with these parameter settings, you receive the following error message:
SQL > startup
ORA-00824: cannot set SGA_TARGET or MEMORY_TARGET due to existing internal settings, see alert log for more information.
Identify the reason the instance failed to start.
A. The PGA_AGGREGATE_TARGET parameter is set to zero.
B. The STATISTICS_LEVEL parameter is set to BASIC.
C. Both the SGA_TARGET and MEMORY_TARGET parameters are set.
D. The SGA_MAX_SIZE and SGA_TARGET parameter values are not equal.
| 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.
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
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