DBA_HIST_DB_CACHE

DBA_HIST_DB_CACHE_ADVICE

DBA_HIST_DB_CACHE_ADVICE displays historical predictions of the number of physical reads for the cache size corresponding to each row. This view contains snapshots of V$DB_CACHE_ADVICE.

Column	Datatype	Description
`SNAP_ID`	`NUMBER`	Unique snapshot ID
`DBID`	`NUMBER`	Database ID for the snapshot
`INSTANCE_NUMBER`	`NUMBER`	Instance number for the snapshot
`BPID`	`NUMBER`	Buffer Pool identifier (ranges from 1 to 8)
`BUFFERS_FOR_ESTIMATE`	`NUMBER`	Cache size for prediction (in terms of buffers)
`NAME`	`VARCHAR2(20)`	Buffer pool name
`BLOCK_SIZE`	`NUMBER`	Block size in bytes for buffers in the pool (the standard block size, the power of 2 non-standard block sizes, 2048, 4096, 8192, 16384, or 32768)
`ADVICE_STATUS`	`VARCHAR2(3)`	Status of the advisory: `ON` - Currently running `OFF` - Disabled (the estimates are historical and calculated when last enabled)
`SIZE_FOR_ESTIMATE`	`NUMBER`	Cache size for prediction (in megabytes)
`SIZE_FACTOR`	`NUMBER`	Size factor with respect to the current cache size
`PHYSICAL_READS`	`NUMBER`	Physical reads for the cache size
`BASE_PHYSICAL_READS`	`NUMBER`	Base physical reads for the cache size
`ACTUAL_PHYSICAL_READS`	`NUMBER`	Actual physical reads for the cache size