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Re: db block size, too big wasting buffer?

From: Nuno Souto <nsouto_at_optushome.com.au.nospam>
Date: Tue, 25 Jun 2002 17:09:48 +1000
Message-ID: <3d1818ae$0$28008$afc38c87@news.optusnet.com.au>


In article <3D175E5F.6090202_at_europe.com>, you said (and I quote):
> Hi
>
> I am about to create a OLTP database of 16KB in 8.1.7, I have always
> read that dont make the db block size too big or we would be wasting
> data buffer. Is this true?

No. It is most definitely not true. You cannot "waste" data buffer by changing block sizes. The two things are not related.

What you can have is a situation where you may be doing I/O in bigger "chunks" (buffers) than you really need. That's all.

But even then, you are not "wasting data buffers". No way.

> Some say that db block size is another Oracle Myth, it does not really
> matter, is this a correct statement?
>
>

It does matter and a lot. But not for the "traditional" reasons. In 9i, you have the option of multiple buffer sizes in the same database. In 8i, you don't. So consider looking at 9i if at all possible.

As for 8i, 16K is a little above what I feel comfortable with from past experience. I'd stick to 8K across the board (that's Unix and NT). Even though others here have had good experiences with 16K in NT, I've always had problems.

8K seems to be the sweet spot for database block size at 8i with the largest sample of "types of database", "types of OS" and "types of application".

Having said that, there is always the exception. It may well be that the db you're after and its load characteristics would warrant a smaller block size. Very hard to say without more data.

-- 
Cheers
Nuno Souto
nsouto_at_optushome.com.au.nospam
Received on Tue Jun 25 2002 - 02:09:48 CDT

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