Re: Schema Placement for Purchased Apps

> Block size is a function of filesystem, not whim, application type, or
> anything else.

I'll agree and disagree with you there...

I agree because block size should not be set on a whim, nor should it be an unfounded guess.

I disagree because, for example, on a file system that has a 64k physical block size, you could set Oracle's block size to (again, for example):

1. 8K with block multi-read of 8,
2. 2k with block multi-read of 32,
3. 64k with block multi-read of 1.

As far as raw performance cost, these are equivalent (they all cause Oracle to read a single os-level disk block at a time), however, there are distinct pluses and minuses to using each as far as Oracle itself goes.

As I understand it (and please correct me if I'm wrong), as long as you read entire O/S-level disk data blocks at a time you are fine. If you have a warehousing type of application, then it might, for example, be convenient to read several O/S-level data blocks at a time, and you might get better Oracle space usage if you have larger Oracle-level data blocks, so you might want something like (assuming 64K disk physical block again) 64k Oracle block size with 4 block multi-read, for example. Again,this heavily depends on the application, but the idea is the same. Received on Thu Apr 10 2003 - 06:20:54 CDT