DBA_HIST_SGA_TARGET_ADVICE provides historical information about the SGA_TARGET initialization parameter.
| 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 | 
| SGA_SIZE | NUMBER | NOT NULL | Size of the SGA | 
| SGA_SIZE_FACTOR | NUMBER | NOT NULL | Ratio between the SGA_SIZEand the current size of the SGA | 
| ESTD_DB_TIME | NUMBER | NOT NULL | Estimated DB_TIME for this SGA_SIZE | 
| ESTD_PHYSICAL_READS | NUMBER | Estimated number of physical reads |