<div dir="ltr">At-least-once semantics is one of the reasons to look beyond Resque/Sidekiq once you've moved the overhead of message management off your database (DelayedJob).<div><br></div><div>On a related note Salvatore Sanfilippo (antirez) has been working on Disque which sounds interesting. He published a blog post overnight on how that's going <a href="http://antirez.com/news/88">http://antirez.com/news/88</a></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><b>Garry Shutler</b><div><div><a href="http://twitter.com/gshutler" target="_blank">@gshutler</a></div><a href="http://gshutler.com/" target="_blank">gshutler.com</a></div></div></div></div>
<br><div class="gmail_quote">On 16 March 2015 at 10:01, James McCarthy <span dir="ltr"><<a href="mailto:james@lety.co" target="_blank">james@lety.co</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
I've used and swear by RabbitMQ, avoiding all the DB as a Q
locking/transaction/commit issues.<br>
<br>
Handy thing with RabbitMQ is that it includes an acknowledge
configuration which can be auto or manual.<br>
<br>
With manual, you need to call the acknowledge method before the
message is removed from the queue.<br>
<br>
James.<div><div class="h5"><br>
<br>
<div>On 16/03/15 09:12, Najaf Ali wrote:<br>
</div>
</div></div><blockquote type="cite"><div><div class="h5">
<div dir="ltr">Hi all,
<div><br>
</div>
<div>I'm trying to identify some general good practices (based
on real-life problems) when it comes to working with async job
queues (think DJ, Resque and Sidekiq).</div>
<div><br>
</div>
<div>So far I've been doing this by collecting stories of how
they've failed catastrophically (e.g. sending thousands of
spurious SMS's to your customers) and seeing if I can identify
any common themes based on those.</div>
<div><br>
</div>
<div>Here are some examples of what I mean (anonymised to
protect the innocent):</div>
<div><br>
</div>
<div>* Having a (e.g. hourly) cron job that checks if a job has
been done and then enqueues the job if it hasn't. It knows
this because the successfully completed job would leave some
sort of evidence of completion in e.g. the database. If your
workers go down for a day, this means the same job would be
enqueued over and over again superfluously.</div>
<div><br>
</div>
<div>* Sending multiple emails (hundreds) in a single job lead
to a problem where if just one of those emails (say the 24th)
fails to be delivered, the entire job fails and emails 1-23
get sent again when your worker retries it again and again and
again.</div>
<div><br>
</div>
<div>* With the workers/app running the same codebase but on
different virtual servers, deploying only to the application
server (and not the server running the workers) resulted in
the app servers queueing jobs that the workers didn't know how
to process. </div>
<div><br>
</div>
<div>It would be great to hear what sort of issues/incidents
you've come across while using async job queues like the
above. I don't think I have enough examples to make any
generalisations about the "right way" to use them yet, so more
interested in just things that went wrong and how you fixed
them at the moment.</div>
<div><br>
</div>
<div>Feel free to reply off-list if you'd rather not share with
everyone, I intend to put the findings together in a blog post
with a few guesses as to how to avoid these sorts of problems.</div>
<div><br>
</div>
<div>All the best,</div>
<div><br>
</div>
<div>-Ali</div>
<span></span></div>
<br>
<fieldset></fieldset>
<br>
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<br>
<pre cols="72">--
James McCarthy
Software Consultant
LetyCo
Mob: 07577006897
Email: <a href="mailto:james@lety.co" target="_blank">james@lety.co</a>
<a href="http://lety.co" target="_blank">lety.co</a></pre>
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