session variables and performance

[Giles]

I have an IIS6 ASP site that has up to 200 "logged in" users at a time.
About 30 session variables are set at each login, containing user
information like their name, preferences etc.

My question is, does having lots of session variables impact site
performance, or is this only a problem when there are millions of concurrent
users, like with Facebook? (i.e. I don't have to worry)
Thanks

[Bob Barrows]

Giles wrote:
> I have an IIS6 ASP site that has up to 200 "logged in" users at a
> time. About 30 session variables are set at each login, containing
> user information like their name, preferences etc.
>
> My question is, does having lots of session variables impact site
> performance,

Of course. Each session consumes some memory ...

> or is this only a problem when there are millions of
> concurrent users, like with Facebook? (i.e. I don't have to worry)

Can't answer that question. We have no idea what type of data is being
stored (string, numbers, objects ...) or what kind of resources are
available on your web server.

Ar you having performance problems? is that why you asked the question?

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[Giles]

>> My question is, does having lots of session variables impact site
>> performance,
>
> Of course. Each session consumes some memory ...
>
>> or is this only a problem when there are millions of
>> concurrent users, like with Facebook? (i.e. I don't have to worry)
>
> Can't answer that question. We have no idea what type of data is being
> stored (string, numbers, objects ...) or what kind of resources are
> available on your web server.
>
> Ar you having performance problems? is that why you asked the question?

Strings, average 10 characters. Server has 2GB of RAM, 2 x 2GHz
processors.No performance problems yet, but the site is up for redesign, and
I am wondering if I can increase the use of session variables, or if I
should use client side cookies to maintain state between pages. I guess I am
asking whether session variables use just RAM (which I can calculate by
multiplying), or if they are a significant drain on the processor also? i.e.
what is best practice?

[Bob Barrows]

All you can do is test. I've never seen any sort of "best practice" for
this.

Microsoft has a stress-testing tool that might prove useful to you. See:
http://mvolo.com/blogs/serverside/archive/2007/05/17/WCAT-6.3-web-performance-and-scalability-test-tool-released.aspx