Re: Newbie: How to change DB_BLOCK size

Er, I'd question that 'for better performance' before you start. Are you *sure* that the increase is going to give you good payback?

Not being funny, but if you are that unsure of Oracle that you don't know how to re-create the db, you may also not be sure enough to properly assess the impact - both positive and negative - of altering the block size. Maybe you should seek a little outside help?

BTW, in my testing, varying the blocksize on both NT and UNIX systems has usually only given a smallish (less than 5%) performance improvement. Biggest performance boosts for I/O have been disk striping, raw devices (UNIX) and getting the multi_block_read_count right (full tablescans only). Also look at the platform specific Oracle docs., they usually have some good tuning tips.

And test, test, test - with real-world SQL for your system. Don't believe anything you read. Test your own system in a variety of configurations covering *all* the bases (read, write, both sequential, random, and under a variety of loads). Remember, when you change the block size you are changing it for the whole db - redo, rollback, temp, system - as well as your own data/index tablespaces.

MotoX

DAVID SMITH wrote in message <34fa9f81.0_at_newsprime.tidalwave.net>...
>All,
>
>I am new to the DBA world and have installed O 8.0.3 on NT server with the
>default database (ORCL). I would like to change the DB_BLOCK parameter for
>better performance. I understand I have to "rebuild" the database to do
>this. However, I'm not clear as to what rebuilding the database means.
Any
>help would be appreciated.
>
>--David Smith
>dsmith_at_hpti.com
>
>
Received on Mon Jul 06 1998 - 02:26:14 CDT