[Dancer-users] do something after sending response

[Nick Knutov]

Yes, in my case the load can be high and I still want to do some job 
after sending response.

For example, I need to send emails, and it can be done with cron scripts 
(with overhead on serialization), but I need to send emails as soon as 
possible after sending rendered page to upstream/browser.

So, in my case, I can load more back-end instances and do it as 
described to save some seconds between sending response and sending emails.

12.08.2011 16:13, Flavio Poletti пишет:
> On Fri, Aug 12, 2011 at 5:49 AM, Nick Knutov <mail at knutov.com
> <mailto:mail at knutov.com>> wrote:
>
>     I agree, forking is another way to do it, but as far as I know, it
>     can lead to very high load. Also, dying process is a heavy
>     operation, as far as I remember.
>
>
> I don't fully understand the role of server load here.
>
> On the one hand you want to perform those heavy operations inside your
> Dancer process after the page has been delivered. I would say that this
> is reasonable if the load on your server is very low, because you're
> asking your front-end infrastructure to take care of back-end duties as
> well.
>
> On the other hand you're very concerned with load. If this is the case,
> are you sure that blocking your front-end process to carry out the
> back-end duties is the right way to go? You might shave off the fork
> penalties (but you have to do your benchmarking homework here, and
> probably with a reasonable copy-on-write handling you don't suffer that
> much), but this would be nothing compared to how stuck your front-ends
> would become.
>
> If the load is your concern, you should decouple the frontend from the
> backend as much as possible. I'd suggest to serialize the relevant data
> in some way and push to a queue that is dealt with by some other
> process, which might even run on another machine if the load on a single
> server gets too high. If you need more, with proper sharding you could
> also reach full horizontal scalability.
>
> Cheers,
>
>      Flavio.
>
>
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-- 
Best Regards,
Nick Knutov
http://knutov.com
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