[Catalyst] Memory leak under FastCGI?

[Matt Pitts]

We have a Catalyst app that I recently (about a month ago) converted
from running under mod_fcgid to external under mod_fastcgi and it
appears to be leaking memory. There are 2 application backends and they
both suffered oom-killer events within six minutes of one another
yesterday and one of them again this morning after a cron job ran that
experienced some deep recursion calls.

Both backends were running out of PARs when the first OOM events
occurred. To eliminate the PAR setup itself as a cause, I started one of
the backends by directly invoking myapp_fastcgi.pla and its memory
behavior is the same, so I'm pretty confident the invocation via PAR is
not a cause.

I also checked my versions of CGI::FormBuilder to ensure I was up to
3.501 and these all checked out.

I have not yet determined if the conversion from mod_fcgid to
mod_fastcgi external is when the RAM usage started climbing - still
awaiting system reports - but, there haven't been an substantial changes
to the app since then that I would consider potential causes of a memory
leak. I'm guessing it's been there for a while, but it's only now
evident because the app instances were getting automatically recycled by
mod_fcgid and now they're not.

I'm hoping someone here might have some light to shine on common FastCGI
memory leak issues.

Is it generally an acceptable practice to just restart the external
fastcgi process periodically to free its memory?

Any input is greatly appreciated.

v/r
-matt pitts