Re: Veritas Quickio and DB_BLOCK_SIZE

Is this the thread where Thomas says something about:

>I've done the same (recommend 2k blocks). It is true. I am serious.
2k is
>appropriate in some cases. some reasoning:

        NOTE -- 'in some cases'
        NOTE -- 'some reasoning'

and my follow-up post contains:

> Me too -
> Some more reasons:

        (reasons cut)

> It all comes down to knowing the application,
> the environment, the usage patterns, the
> data distribution, and doing the arithmetic.
>
> Have to say though, that unless the file system
> allows for 2K writes (e.g. with Veritas direct I/O
> option) then you generally have to choose
> between an optimum Oracle blocksize and
> an optimum O/S blocksize or move to raw devices

    NOTE -- 'some more reasons'
    NOTE -- 'doing the arithmetic'
    NOTE -- the warning about Oracle and O/S block sizes.

Neither Thomas nor I made a throwaway remark suggesting a specific block size was appropriate - we both stated that we had on occasions used 2K where appropriate. Nor did we add a valueless caveat about 'the application being appropriate', we actually gave concrete reasons why an application may or may not be appropriate.

Jonathan Lewis
http://www.jlcomp.demon.co.uk

Host to The Co-Operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html

Author of:
Practical Oracle 8i: Building Efficient Databases

Screen saver or Life saver: http://www.ud.com Use spare CPU to assist in cancer research.

-----Original Message-----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: 03 October 2001 20:03

|By the way, you are agreeing and disagreeing with
|Jonathan Lewis at the same time. The index efficiency
|on small block size is Jonathan's point he made a
|couple of years ago when he was stating why he
|recommends a 2k block size on an OLTP type database.
|The other index point (scanning an index on a small
|block size) is from Thomas Kyte on the same
|thread...If you disagree with him, you can write him
|an e-mail so you can correct him.

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Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

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