Re: general performance issues
André Warnier wrote:[color=blue]
> If it's too off-topic nevertheless, just send me packing, I won't insist.[/color]
I might be alone in this but I think apache memory use is something all
heavy mod_perl users have to get to grips with, so I mentally
s/java|tomcat/mod_perl/g'd and read your very long email....[color=blue]
> But sometimes it doesn't, and becomes rather slow for a while.[/color]
Find out if it's *actual* slowness or just HTTP requests being queued up
because none of the apache children are free to service the request.[color=blue]
> anything that we would do to improve its generic performance would be
> all the more effective if applied to the production servers, right ?
> or wrong ? in a generic way I mean.[/color]
I agree but with one caveat - memory is very cheap at the moment.
Strike a good balance between spending hours trimming the memory
footprint of your app and buying more RAM.
> The first thing that strikes me, is the huge memory allocated to
> Tomcat and the other Java processes. I wonder if this unavoidable, or
> if it is just misconfiguration on my part.
> The "huge Tomcat application" is unfortunately one that we just buy,
> we can't peek in the code to see what's going on there. We just know
> it is (also) processing some large quantity of XML data, mostly when
> it starts up. That almost paralyses our server for 10 minutes or so
> when we restart Tomcat.[/color]
Tongue in cheek, thats what you get for not rewriting it in perl ;)
Seriously though, in your own apps make sure you're not loading large
XML files fully into RAM before parsing them. Use a SAX or similar
parser to treat large XML files like a stream.[color=blue]
> The other question is, does the memory shown as used by the Apache
> processes seem normal/abnormal to anyone ? This being a prefork
> Apache, if it seems abnormal, what kind of thing should I look at ?
> Or is it so normal that I should not even spend time on it ?[/color]
Those are very lean looking apache's by my own experience, I don't think
you'll do much better.
hope that's useful,