[Mongrel] Upgrading from 1.0.1 to 1.0.5

Luis Lavena luislavena at gmail.com
Mon Feb 25 11:22:53 EST 2008

On Mon, Feb 25, 2008 at 6:57 AM, Matthew Langham
<matthew.langham at indiginox.com> wrote:
> Hi,
>  we have a project where mongrel 1.0.1 has been in use in production
>  for a few months now. Everything works fine except we run into marked
>  performance problems if the setup has been running a couple of weeks
>  without a restart. The general performance slows down quite a bit but
>  restarting everything brings it back to normal.
>  So we are looking at areas that could be relevant and therefore
>  considering upgrading mongrel to 1.0.5.
>  Can anyone provide insight on whether this could help our performance
>  issues?

Maybe no-one will comment this, but most of the "long running process"
problems are not (directly) Mongrel related, but Rails related.

It seems quite common blame Mongrel because it hides behind a simple
"mongrel_rails" script or a cluster of mongrels. But after all,
mongrel is running your Rails application. period.

Mongrel offers to Rails a layer to process the HTTP protocol and serve
the CGI-like information to the Rails Dispatcher, nothing more,
nothing less.

If you don't provide/create custom handlers (in mongrel) that's the
most Mongrel do for Rails.

I've seen several memory leaks from Rails, and tried to pinpoint some
of them, ended repeating the work done in the past by others but that
never got integrated into Ruby or Rails core.

Like, for example, the Benchmark::realtime "abuse" that Rails do and
the huge amount of memory it allocated in the past (now fixed in Ruby
trunk and 1_8 branch).

Migrating to Mongrel 1.0.5 wouldn't fix that, and you will keep
blaming Mongrel for the problem.

I'll suggest you plan a monit/god sweep and respawn strategy for your
rails processes.

Besides that, guess is time for you to start looking at things your
application is using to became slower with the time:

- Use of image processing plugins/extensions/gems like RMagick
- Files opened without proper closing (File.open without a block or
file#close after use of it).
- String concatenation using += instead of <<
- Misused queries over associations in your ActiveRecord models (use
of length to determine the size of a associated array instead of

Those are the more common mistakes.

Luis Lavena
Multimedia systems
A common mistake that people make when trying to design
something completely foolproof is to underestimate
the ingenuity of complete fools.
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