Re: Cost of joins?

[Jigal van Hemert]

From: "Martijn Tonies" <m.tonies@stripped>
> Design for understanding, logic and maintenance, not performance.
>
> If you need more performance, throw more hardware at it -
> a larger cache (settings -> memory), faster disks and a faster CPU.

Sorry, but I can't agree with you. Years ago I had to put the DMOZ
(http://www.dmoz.org/) database (2 million records, 100,000 or so categories
at the time) in a MySQL database. Next we had to calculate the number of
sites in a certain category. The 'path' to the category was known, but a
regexp was needed to select the path of one level up. The query took > 30
seconds.
After adding a column for "one level up", adding indexes, optimizing the
query it took only a few hundreds of seconds.

I really don't know how much hardware you would like to use to get these
results?

Regards, Jigal.