hi
when we read a row from a segment do we read the whole block which that
row is located into buffer cache??
Nuno Souto wrote:
> 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.
>
>
Received on Tue Jun 25 2002 - 12:47:22 CDT
