does anybody knows how can I calculate the average redo log
10x in advance.
Look at stats on the database
(need timed_statistics = TRUE for meaningful stats)
A raw figure will be
redo write time / redo writes = avg. redo write time
This will be in writes/ 10s of millisec
The quickest log switch interval is something different
there is a script on http://www.ixora.com.au called
log_switch_interval.sql to determine this.
I suppose some extrapolation could be used to determine the average log switch interval
i.e redo size / redo write time = avg redo write speed
in bytes/10s of millisec
Then the average time will be the
redo log size / avg redo write speed
Performance... Push the envelope!
you can know that from v$log_history, doing something like :
select (a.first_time - b.first_time) * 3600 * 24
from v$log_history a, v$log_history b
where b.sequence#=a.sequence# - 1;
this will give you time in seconds for each redo logs. from there you can get min/max/avg times.
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