Sorry, I should have specified that I'm already using PerlIS. 

I'm specifically interested in whether there are any scalability issues with
DBI, since it appeared to be proliferating DBI threads that were causing the
problem. We fixed it on the fly by throwing more RAM and a second processor
into the server, after which things went well. As mentioned, I'm also
interested in advice on stress-testing such an app to forestall such
problems in the future.

---------------FROM-------------------
David R. Miller
Manager, Computer-Based Testing
Medical Council of Canada
[EMAIL PROTECTED]
(613) 521-6012
(613) 521-9722 (fax)
-----------------------------------------


-----Original Message-----
From: Trevor Joerges [mailto:[EMAIL PROTECTED]]
Sent: 27 November 2001 9:45 p.m.
To: 'MILLER David R.'; 'Perl-Win32-Web (E-mail)'
Subject: RE: Web app advice


Scalability with Perl CGI applications is a known issue. The problem is that
the Perl interpreter loads every time as a new process in protected memory.
Alternatives to increase scalability are FastCGI, mod_perl (for Apache) or
Perl ISAPI on WinNT. 

<snip>

-----Original Message----- 
From: MILLER David R. [mailto:[EMAIL PROTECTED]] 
Sent: Tuesday, November 27, 2001 4:31 PM 
To: Perl-Win32-Web (E-mail) 
Subject: Web app advice 


I've created a Perl-driven web app that delivers a high-stakes examination 
to remote computer labs. We recently ran a session and experienced some 
problems that I am seeking advice on. 
Perl v5.6.1, ... Binary build 629 
DBI::DBD.pm,v 10.8 2000/06/11 00:06:02 
DBD::ODBC.pm,v 1.12 1998/08/14 19:29:50 
Windows 2000 
IIS 5 
SQL Server 7.0 
Although things went well in testing, in practice our server memory usage 
went nuts past a threshold of perhaps 100 simultaneous users. We're not sure

why, but the clues seem to point to the DBI. I realize that specific advice 
is impossible without seeing code, but at the moment I'm asking two general 
questions: 
1. Are there scalability issues with DBI/DBD/ODBC that I should be aware of?

(The last time we ran the exam I was still using Win32::ODBC and didn't see 
this particular problem, although the current code is definitely more 
database-intensive.) 
2. The big lesson is that we have to stress-test our app. I need to create a

host of virtual candidates taking the exam so I can try out different 
components and different scenarios. Does anyone have recommendations for a 
suitable tool for doing this, Perl-based or otherwise? I can't say that 
price is not a factor, but the costs and stress associated with a server 
meltdown are pretty considerable. 
TIA 
---------------FROM------------------- 
David R. Miller 
Manager, Computer-Based Testing 
Medical Council of Canada 
[EMAIL PROTECTED] 
(613) 521-6012 
(613) 521-9722 (fax) 
----------------------------------------- 
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