Re: Oracle slowed down

From: Bob Jones <email_at_me.not>
Date: Sat, 22 Apr 2006 01:05:09 GMT
Message-ID: <9jf2g.50872$_S7.22123@newssvr14.news.prodigy.com>

"HansF" <News.Hans_at_telus.net> wrote in message news:pan.2006.04.21.18.16.13.331774_at_telus.net...
> On Fri, 21 Apr 2006 08:33:05 -0700, stevedhoward wrote:
>
>> I think I understand where Bob is coming from. I think he is saying that
>> *after* you have tuned the application, you could look to get more of the
>> remaining required buffers from Oracle memory than from disk (whatever
>> that is nowadays, with OS cache, SAN cache, etc.). One logical way (once
>> again, after you have removed the low hanging SQL fruit) is to
>> "encourage"
>> Oracle to get more blocks that are needed from memory rather than "disk".
>>
>
> The one issue I have with BHCR is simple - people have gotten into the
> habit of using it as the primary tuning tool.
>

It is just one of the tools.

>
> However, makes a huge assumption ... it ONLY gives us information about
> whether we are finding stuff in the cache - again. Useless if noone else
> is interested in the same information,
>
> A 100% BCHR can just as easily identify a grossly overconfigured cache as
> it can identify popular data sets. In both cases the misinterpretation is
> that it looks good.
>

That's why we need to tune the buffer cache. Received on Fri Apr 21 2006 - 20:05:09 CDT