DBA_HIST_SYSMETRIC_SUMMARY displays a history of statistical summary of all metric values in the System Metrics Long Duration group. This view contains snapshots of V$SYSMETRIC_SUMMARY.
| Column | Datatype | NULL | Description | 
|---|---|---|---|
| SNAP_ID | NUMBER | NOT NULL | Unique snapshot ID | 
| DBID | NUMBER | NOT NULL | Database ID for the snapshot | 
| INSTANCE_NUMBER | NUMBER | NOT NULL | Instance number for the snapshot | 
| BEGIN_TIME | DATE | NOT NULL | Begin time of the interval | 
| END_TIME | DATE | NOT NULL | End time of the interval | 
| INTSIZE | NUMBER | NOT NULL | Interval size (in hundredths of a second) | 
| GROUP_ID | NUMBER | NOT NULL | Group ID | 
| METRIC_ID | NUMBER | NOT NULL | Metric ID | 
| METRIC_NAME | VARCHAR2(64) | NOT NULL | Metric name | 
| METRIC_UNIT | VARCHAR2(64) | NOT NULL | Unit of measurement | 
| NUM_INTERVAL | NUMBER | NOT NULL | Number of intervals observed | 
| MINVAL | NUMBER | NOT NULL | Minimum value observed | 
| MAXVAL | NUMBER | NOT NULL | Maximum value observed | 
| AVERAGE | NUMBER | NOT NULL | Average over the period | 
| STANDARD_DEVIATION | NUMBER | NOT NULL | One standard deviation | 
| SUM_SQUARES | NUMBER | ??? |