Alex Greg wrote:
Geoffrey Young wrote:
[...]
Thanks for your response. Sorry I wasn't clear; the httpd processes don't actually kill the server, they just slow Apache right down to the point at which it doesn't respond to requests any more. I am still able to get onto the box and kill the processes etc. without having to do a hard reboot or anything. My question is what's causing Apache to get into the state where it can't fork any more shells from Perl.
This is because a shell call to date ($date = `date`;) is failing - this
is most likely what's causing the failure to fork we see above.
if you want to avoid that shell call try POSIX::strftime() instead.
We have quite a lot of calls via backticks throughout our code - and not just for things like date that are trivially replaceable. Would you recommend replacing these as far as possible?
Yes because calling the shell is fairly slow if there are any perl-modules you could use these instead and it will certainly give you a performance boost.
What calls do you make, are these custom programs? If not I'd take a look at CPAN maybe someone has already written a Perl-Module which does exactly what you need else you could maybe write it your own. I have done this for example librsvg because I wanted to avoid calls to the shell inside my httpd-processes.
Hi,
We have some calls to ps that parse the output - I suppose we could replace these with Proc::ProcessTable. The rest of it is just date, and stuff that we can replace with either system() or Perl built-ins.
My concern though, is that this is a symptom of another problem, as has been suggested earlier. I have activated mod_status, but since this problem doesn't occur very often (and when it does, renders the server unable to process requests, hence I won't be able to view the status), I'm not sure how it will help. Looking at it now, I can see 7 servers in state "Waiting for connection", and 4 in state "Sending reply", which I assume is fairly normal.
I will keep watching this and start work on replacing the backticks. Any further suggestions would be very much appreciated.
Regards,
-- Alex
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