[dancer-users] blocking

David H untg99 at gmail.com
Tue Nov 17 23:48:55 GMT 2015


Thanks for the response, I think my original email basically outlined my
issue, but I will break it down.

If 10 people visit my page at the moment, and the page has to retrieve
database/memcached info for the 10 people, and it takes 1 second to do all
the pre-work to load the page, then each of those requests for each person,
is done separately, taking a total of 10 seconds for the last person to
retrieve their data, since it has to wait for each other process to finish
before attending to the next person.

At a basic level in nodejs, you do this (as an example):

router.get('/', function (req, res, next) {
   Post.find(function(err, Patients) {
    if (err) { return next(err) }
    res.json(People)
   },'Firstname Surname')
})

And although this is per session blocker in node, it still allows other
sessions to continue.
I want to know how to achieve this or a similar effect in Dancer2. Or, do I
just look at it as an issue with Perl and solve it through something like
AnyEvent::Util::fork_call


David



On Wed, Nov 18, 2015 at 12:32 AM, Rick Leir <richard.leir at canadiana.ca>
wrote:

>
> On Tue, Nov 17, 2015 at 7:00 AM, <dancer-users-request at dancer.pm> wrote:
>
>>
>>     delayed {
>>       my $TextToWrite = ReturnText();
>>       sleep(10); # Do something that takes a few seconds
>>       content "$TextToWrite";
>>       done;
>>    };
>
> The sleep call will always cause blocking, even a sleep(0). Likewise a
> flush. In the sense that there is a context switch to some other thread or
> process.
>
> How are you testing whether it is blocking? Sorry, I do not know what you
> are trying to do.
>
> Linux will not schedule a cpu intensive task to the exclusion of I/O. You
> can affect its scheduling using nice:
>
> http://stackoverflow.com/questions/2012852/control-a-perl-scripts-cpu-utilization
>
> If you really want nonblocking then you can look at nice for io
> http://linux.die.net/man/1/ionice
> or spawn a C program with pthreads and freeze your screen!
> cheers -- Rick
>
>
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>
>
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