Re: write handlers with C or modperl?

On 22.07.2016 11:00, [email protected] wrote:
> Hello,
>
> We have some handlers which were written by modperl for API endpoints.
> yes developing a apache handler with modperl is so easy and quick.
> but for better performance we also consider the C handler.
> (one of the APIs has got 1,500,000 accesses by unique clients)
> Do you think if it's valuable to change the handler from modperl to pure C? for C coding
> we have to take more time to develop, debug and maintain.
>

You have asked the question, and partially answered it yourself.
(Just ad the fact that to use mod_perl, means having a perl interpreter in each of your 
Apache httpd children processes, which is a significant memory overhead).

Ask yourself also if you need perl in Apache for anything else than these "some" handlers.
If you do, then you have to keep perl anyway, and you would not gain anything (in terms of 
memory) by moving your handlers to C.

As to the overall question, nobody can answer this but yourself.

My company runs a bunch (dozens, not hundreds) of websites for customers, under 
Apache/mod_perl, since many years.  The applications are customised and quite 
sophisticated, but the individual traffic on each website is moderate (not millions per 
day like you).

Over these many years, we have found mod_perl *invaluable* in terms of the flexibility and 
rapid development that it provides to us, to accomodate a wide range of ever-changing 
customer requirements in terms of data-entry, user authentication, input and output 
filtering, etc. etc.
(and not least, the availability of CPAN modules, to achieve almost anything you can dream 
of).
So we would not even dream of doing without mod_perl or something at least equivalent; and 
there /is/ nothing else really equivalent under Apache httpd, when it comes to interacting 
more deeply with the HTTP request/response cycle than just running some CGI scripts.

But if your applications are different (more standard and stable over time e.g.), then 
maybe you can squeeze some additional performance by converting all or some of your 
handlers to C.  But again, you have to decide that for yourself.


I believe that it is maybe the "drama" of mod_perl : it is so powerful, and so flexible, 
that you kind of get used to it and blasé.  Using it, nothing to do with HTTP seems 
impossible anymore, and nothing requires very large resources or a lot of time to do.
Consequently, a development team using mod_perl does not need to get very large, to 
achieve quite complex things and keep them running.  And consequently, such teams tend to 
remain small and have small budgets, which does not give them (or mod_perl) a very high 
profile.

To get back to your question, maybe there is an intellectual experiment that you can do : 
Imagine that tomorrow, you get a new management directive, saying that within 6 months all 
usage of perl and mod_perl on your websites needs to be stopped.
And try to figure out what this would cost, in terms of finding alternatives, 
implementing them and maintaining them over time.