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Oracle® Database Reference
11g Release 2 (11.2)

E40402-10
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V$MTTR_TARGET_ADVICE

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.