V$MTTR_TARGET_ADVICE

Oracle 11gR1

V$MTTR_TARGET_ADVICE displays rows that predict the number of physical I/Os for the MTTR corresponding to each row. The rows also compute a physical I/O factor, which is the ratio of the number of estimated I/Os to the number of I/Os actually performed by the current MTTR setting during the measurement interval.

The content of the view is empty if MTTR advisory has not been turned on since database startup. Otherwise, it returns the advisory information collected. If advisory is currently off, then this information comes from the last time MTTR advisory was on. FAST_START_MTTR_TARGET must be set to a nonzero value if the STATISTICS_LEVEL parameter is dynamically modified to turn MTTR advisory on.

If the FAST_START_MTTR_TARGET parameter is changed while MTTR advisory is on, then MTTR advisory is temporarily turned off until the new FAST_START_MTTR_TARGET setting takes effect. During this transition period, the contents of V$MTTR_TARGET_ADVICE reflect the simulation result for the old MTTR setting.

Column	Datatype	Description
MTTR_TARGET_FOR_ESTIMATE	NUMBER	MTTR setting being simulated. Equal to the current MTTR setting if this is the first row of the view.
ADVICE_STATUS	VARCHAR2(5)	Current status of MTTR simulation: · ON · READY · OFF
DIRTY_LIMIT	NUMBER	Dirty buffer limit derived from the MTTR being simulated
ESTD_CACHE_WRITES	NUMBER	Estimated number of cache physical writes under this MTTR
ESTD_CACHE_WRITE_FACTOR	NUMBER	Estimated cache physical write ratio under this MTTR. It is the ratio of the estimated number of cache writes to the number of cache writes under the current MTTR setting.
ESTD_TOTAL_WRITES	NUMBER	Estimated total number of physical writes under this MTTR
ESTD_TOTAL_WRITE_FACTOR	NUMBER	Estimated total physical write ratio under this MTTR. It is the ratio of the estimated total number of physical writes to the total number of physical writes under the current MTTR setting.
ESTD_TOTAL_IOS	NUMBER	Estimated total number of I/Os under this MTTR
ESTD_TOTAL_IO_FACTOR	NUMBER	Estimated total I/O ratio under this MTTR. It is the ratio of the estimated total number of I/Os to the total number of I/Os under the current MTTR setting.

Note:

1.

select * from V$MTTR_TARGET_ADVICE;

MTTR_TARGET_ FOR_ESTIMATE	ADVICE_ STATUS	DIRTY_ LIMIT	ESTD_CACHE_ WRITES	ESTD_CACHE_ WRITE_FACTOR	ESTD_ TOTAL_ WRITES	ESTD_TOTAL_ WRITE_ FACTOR	ESTD_ TOTAL_IOS	ESTD_TOTAL_ IO_FACTOR
35	READY	2105	1321425835	7.0647	1382179252	5.5778	1792121412	2.7247
85	READY	44774	287109761	1.535	347863178	1.4038	757805338	1.1521
136	READY	88295	211078845	1.1285	271832262	1.097	681774422	1.0365
186	READY	130964	194567134	1.0402	255320551	1.0303	665262711	1.0114
237	READY	174254	187046846	1	247800263	1	657742423	1

Oracle dynamic performance views