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Well,
I guess that I disagree. Buffer hit radio does matter as one of the performance
indicators, but
certainly not the only one. Your and Mr. Milsap thesis
is that LIO also is very expensive and its cost
is far
from being negligible, so having gazillion of LIOs instead of 100 times smaller
number of PIOs will
not
make our system run faster. BHR alone cannot be used to judge to overall health
of the system, but
thebn
again, there is no such thing as the "overall health of the system". It's the
users of the system who
will
say whether the performance is satisfactory or not, and
I'm usually tuning an application, not an
imaginary "overall system". Low cache hit ratio
usually tells me that I do have a hog who is using lots
of
PIOs. By my experience, it usually is a very good indicator
that something is wrong, at least on an OLTP
system. So, after all, I do find BHR a
useful indicator, but by no means the only one or the most important
one.
Event 10046, SQL_TRACE (level 1 of 10046), explain plan and v$session_event
still are the tools
I need
most, but I still do need BHR as an indicator.
Mladen Gogala
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Title: RE: missed Anjo's webcast..
- RE: missed Anjo's webcast.. Gogala, Mladen
- RE: missed Anjo's webcast.. Rajesh . Rao
- RE: missed Anjo's webcast.. Post, Ethan
- RE: missed Anjo's webcast.. MacGregor, Ian A.
- RE: missed Anjo's webcast.. Cary Millsap
- RE: missed Anjo's webcast.. Jesse, Rich
- Re: missed Anjo's webcast.. Mladen Gogala
- RE: missed Anjo's webcast.. MacGregor, Ian A.
- RE: missed Anjo's webcast.. Jared . Still
- RE: missed Anjo's webcast.. Freeman, Robert
- RE: missed Anjo's webcast.. Cary Millsap
