Re: db block size, too big wasting buffer?

"Don Burleson" <don_at_burleson.cc> wrote in message news:998d28f7.0206301512.411700f9_at_posting.google.com...
> Sure, blocksize matters a lot:
>
> In a one-side-fits-all 8.1.7 install, you must choose the best overall
> blocksize based on several factors:
>
> 1 - The number of index accesses - Oracle index range scans love large
> blocksizes, and on my 9i systems, I place indexes in a 32k tablespace.
>
> 2 - The amount of random OLTP access - If you are randomly accessing
> 80-byte rows, it would be a huge waste of db_block_size to read-in
> unwanted row data with large blocksizes.
>
> (BTW, this quandry was the main reason for the multi-blockdsize
> feature of 9i)!

Says who?

The main reason for it was transportable tablespaces. In fact, about the only reason. As is evident from Oracle's own documentation on the feature.

>
> On an 8.1.7 Data warehouse, the choice is between 8k and 16k. If your
> db is heavily indexes,, you might think about 16k. I use this query:
>
> select sum(blocks) from dba_segments where segment_type = 'INDEX';
> select sum(blocks) from dba_segments where segment_type = 'TABLE';
>
> Hope this helps . . . .

If perpetuating myths is helping....

HJR Received on Mon Jul 01 2002 - 03:56:06 CDT