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
Oracle DBA
Phone: (203)
459-6855
Email:
[EMAIL PROTECTED]
Moi wrong ;-) Jeeh, human after all
To summarize the webcast:
db-block-buffers do mattter. Too many LIO do
matter. Too many PIO do matter. But Buffer Cache Hit ratio doesn't matter
....... End user satisfaction does matter.
I am always willing to clarify any points that
I made, you just have to ask me l ....
Anjo.
----- Original Message -----
Sent: Thursday, August 08, 2002 5:43
PM
Subject: RE: missed Anjo's
webcast..
Guys,
I had this dream that I missed the webcast - which I
did. However, someone said it wasn't very interesting but the
conversation of the people (gurus) left over was very interesting as there
was good solid evidence that he was incorrect and db_block_buffers do
matter. Kind of inline with the discussion about redos yesterday and
my indexing/partition issues - hmmm.
-----Original Message-----
From:
Mladen Gogala [mailto:[EMAIL PROTECTED]]
Sent: Thursday, August 08, 2002 1:38 AM
To: Multiple recipients of list ORACLE-L
Subject: Re: missed Anjo's webcast..
Www.precise.com, go to Events->webcasts...
On 2002.08.08 00:53 Madhusudhanan Sampath wrote:
> Are transcript documents available anywhere?
>
> Regards
> Madhusudhanan S
>
>
>
>
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> Author: Madhusudhanan Sampath
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