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Re: db_block_buffer

From: Howard J. Rogers <howardjr_at_www.com>
Date: Thu, 28 Dec 2000 17:42:33 +1100
Message-ID: <3a4ae0d9@news.iprimus.com.au>

"Daniel A. Morgan" <dmorgan_at_exesolutions.com> wrote in message news:3A483B15.52588C51_at_exesolutions.com...
> > Oracle 8.0.5 Solaris 2.6
> > I"ve recently been told (by a database engineer and upper management)
> > to increase our db's db_block_buffers from 15000 to 30000!
> > I've tried kicking and screaming, tried to explain that you just don't
> > randomly start doubling such parameters because the hit ratio is 75%.
> > They seem to think it's going to solve all performance problems, but I
> > know deep down
> > it's just going to cause more issues.
> >
> > Just wanting to rant.
> >
> > TIA
>
> In the time it took you to rant you could have done it. And what would the
> down-side have been? You change the parameter, you benchmark the system,
> and you go on with your life. Personally, I agree with the others that the
> change suggested is far too conservative.
>
> If all other things are equal (decent SQL with the right indexes), the
> fastest way to improve the performance of an Oracle database is to grab
> every bit of RAM on the system, and if you run out of RAM ... add more and
> grab that too.

Yes, but Daniel... Oracle DBAs are expected to show a little bit of *intelligence* about their use of resources, and piling on the RAM is fine -until someone asks you where best to pile it. And as we all (ought to) know, bunging extra RAM into the buffer cache if it's hit ratio is already around the 85-90% mark is just a *Waste of RAM*.

A much better use of RAM "other things being equal" is to apply that RAM to the Library Cache.

I'd be extremely impressed if you can merely by look at the number of data buffers and claim that that is 'too conservative' ...and be correct. Size isn't everything, Daniel, as you should have learnt by now. It's not what you've got, but how you hit it.

Regards
HJR
>
> Dan Morgan
>
Received on Thu Dec 28 2000 - 00:42:33 CST

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