Effect of increased users on query time - rec specs

I have just started my first big project and I am having trouble predicting
the system specs that will be required. At present during trials the site
has around 15 users, although this will go to 350 when it is launched.

Most of the pages execution time should not scale with the increase in users
but there are a few report pages which calculate and order the information
entered by the users.

Measuring the page on my development machine (Duron 1.2, 768MB PC133, WinXP,
running apache 1.3.22, mysql 4.0.15and php4.3.4)...

One page I am currently getting 0.2-0.3 seconds. It uses phplib templates
and it executes 9 queries at present, 1 of which I predict will scale. It
calculates the mean, standard deviation and total of around 90 measures
using results from 15 users.

I do have a few nightmare pages for the regular users which execute 150+
queries (mixture of selects and updates).

Can anyone predict what will happen with 300+ users?

I am thinking max load being 20 regular users logged in with 2 users viewing
reports.

The machine I am currently looking at is P4 2.4, 512DDR with Linux. Will
this be suitable?

Thanks for any help/advice you can offer..
Greg

re: Effect of increased users on query time - rec specs

[color=blue]
> Can anyone predict what will happen with 300+ users?
>
> I am thinking max load being 20 regular users logged in with 2 users viewing
> reports.
>
> The machine I am currently looking at is P4 2.4, 512DDR with Linux. Will
> this be suitable?[/color]

I would need to see your "monster" pages, but I think you should be
okay. If you have that many queries on one particular page, it might be
time to start thinking about more powerful options than PHP.

Either Java or Microsoft products would allow you to embed your queries
outside your presentation layer, and optimize there.

However, if you're only talking 2 people viewing these complex reports
at a time, I think you're fine.

Lukas

re: Effect of increased users on query time - rec specs

[color=blue]
> Can anyone predict what will happen with 300+ users?
>
> I am thinking max load being 20 regular users logged in with 2 users viewing
> reports.
>
> The machine I am currently looking at is P4 2.4, 512DDR with Linux. Will
> this be suitable?[/color]

I would need to see your "monster" pages, but I think you should be
okay. If you have that many queries on one particular page, it might be
time to start thinking about more powerful options than PHP.

Either Java or Microsoft products would allow you to embed your queries
outside your presentation layer, and optimize there.

However, if you're only talking 2 people viewing these complex reports
at a time, I think you're fine.

Lukas