Re: BLOCK SIZE QUESTION

In article <6l9pa5$1os$1_at_news.worldonline.nl>, vernes.j_at_consunet.nl (John Vernes) wrote:

> My question is as follows:
>
> Our application has a couple (4) of very big tables of which 2 are
> almost always querried by indexes. The other 2 are first under heavy
> fire of inserts (10 million) and updates (couple of million) and
> accordingly
> used for frequent querrying to check data againt other data previously
> acquirred data.
> This querying of indexes I can almost certainly guarantee is pinpointing
> in blocks squattered all over the disk (using read 0).
> Currently we are using an Oracle blocksize of 8K and a NT disk blocksize
> of 4K with a striping size of 16K.
>
> Is there anyone who can tell me what the result will be when I make the
> Oracle blocksize 2K?
> And would it be usefull to also adjust the NT disk blocksize even when
> we can't change the stripe size?

Changing the block size is a very big job!! I'm not sure that you will get massive performance improvements.

>
> As I look at things, I will have more blocks in memory (available
> 350MB) and
> frequently used blocks will be longer in memory than others. Rigth??

The theory sounds about right though!

>
> When doing lots of insert I quess reducing the Oracle/NT blocksize migth
> also be a bad idea or not??
>
>
> Any help is appreciated.
>
> John
>
>
>

Don't reduce the block size if your table rows are very large i.e. would span more than one 2K block.
Inserting into a block would only be affected if this was the case i.e. that the row was very large. Do you do much updating that a.) Affects indexed rows
b.) Increases row length substantially

Hope this is a small help

Luke Received on Sat Jun 06 1998 - 10:03:13 CDT