V$DB_CACHE_ADVICE

Oracle 11gR1

V$DB_CACHE_ADVICE contains rows that predict the number of physical reads for the cache size corresponding to each row. The rows also compute a "physical read factor," which is the ratio of the number of estimated reads to the number of reads actually performed by the real buffer cache during the measurement interval.

Column	Datatype	Description
ID	NUMBER	Buffer pool identifier (ranges from 1 to 8)
NAME	VARCHAR2(20)	Buffer pool name
BLOCK_SIZE	NUMBER	Block size in bytes for buffers in this pool. Possible values: the standard block size, the power of 2 non-standard block sizes, 2048, 4096, 8192, 16384, 32768.
ADVICE_STATUS	VARCHAR2(3)	Status of the advisory. ON indicates it is currently running; OFF indicates it is disabled (in this case 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
BUFFERS_FOR_ESTIMATE	NUMBER	Cache size for prediction (in terms of buffers)
ESTD_PHYSICAL_READ_FACTOR	NUMBER	Physical read factor for this cache size, which is the ratio of the number of estimated physical reads to the number of reads in the real cache. If there are no physical reads in the real cache, the value of this column is null.
ESTD_PHYSICAL_READS	NUMBER	Estimated number of physical reads for this cache size
ESTD_PHYSICAL_READ_TIME	NUMBER	Estimated disk read time
ESTD_PCT_OF_DB_TIME_FOR_READS	NUMBER	Estimated disk time as a percentage of the total time
ESTD_CLUSTER_READS	NUMBER	Estimated total number of blocks foreground processes read from the global cache (Real Application Clusters only)
ESTD_CLUSTER_READ_TIME	NUMBER	Estimated total amount of time, in seconds, foreground processes read from global cache (Real Application Clusters only)

Note:

1.

select * from V$DB_CACHE_ADVICE;

ID	NAME	BLOCK_ SIZE	ADVICE_ STATUS	SIZE_FOR_ ESTIMATE	SIZE_ FACTOR	BUFFERS_ FOR_ ESTIMATE	ESTD_ PHYSICAL_ READ_ FACTOR	ESTD_ PHYSICAL_ READS	ESTD_ PHYSICAL_ READ_ TIME	ESTD_ PCT_ OF_ DB_ TIME_ FOR_ READS	ESTD_ CLUSTER_ READS	ESTD_ CLUSTER_ READ_ TIME
3	DEFAULT	16384	ON	1200	0.0996	75450	1.6834	1298934683	5469792	55.4	0	0
3	DEFAULT	16384	ON	2400	0.1992	150900	1.5912	1227809474	5092428	51.5	0	0
3	DEFAULT	16384	ON	3600	0.2988	226350	1.5046	1160995138	4737936	48	0	0
3	DEFAULT	16384	ON	4800	0.3984	301800	1.4229	1097972836	4403564	44.6	0	0

Oracle dynamic performance views