Re: mod_ruby, ebury and module problem

On Wed, Dec 29, 2004 at 09:35:35AM -0500, Alex Reyes wrote:
> Arnaud LACOMBE wrote:
> >Hello,
> >
> >I encoured a strange problem this afternoon with mod_ruby. I use
> >mod_ruby with eruby for my CGI which require some module. When I load
> >many time a given page the result is not the same each time, The result
> >is sometimes the one given by an old version of the module.
> >
> >The only one way curently to solve the problem is to restart apache ...
> 
> I get virtually the same thing if I make changes to some files.  I'm not 
> sure if the problem is only with "require'd" .rb files, or if it also 
> happens with .rhtml-only changes.  But I know it happens, and restarting 
> Apache fixes it.
> 
> It's gotten to the point that I restart Apache on any significant 
> change, which is about 80% of the time.

Is this not simply a reflection of the fact that each httpd worker process
has its own Ruby interpreter instance?

If you change a require'd file, then existing httpd worker processes will
not notice it and will continue to run the old code. But any new worker
processes which are spawned will have fresh Ruby interpreters which will
load the source from scratch, and thus get the new version.

Workers are spawned and die dynamically depending on the level of request
load, and can be controlled in httpd.conf. However, you're likely to always
have at least one around. Restarting apache ensures they are all killed and
restarted. Or you could set MaxRequestsPerChild to ensure that each worker
process eventually dies and is restarted.

Regards,

Brian.