Re: Request Queueing after deploy + USR2 restart

[Sarkis Varozian <svarozian@gmail.com>]

Eric,

Thanks for the quick reply.

We are on Ruby 2.1.5p273 and unicorn 4.8.3. I believe our problem is the
lazy loading - at least thats what all signs point to. I am going to try
and mock request some url endpoints. Currently, I can only think of '/', as
most other parts of the app require a session and auth. I'll report back
with results.



On Wed, Mar 4, 2015 at 12:35 PM, Eric Wong <e@80x24.org> wrote:

> Sarkis Varozian <svarozian@gmail.com> wrote:
> > On Wed, Mar 4, 2015 at 12:17 PM, Michael Fischer <mfischer@zendesk.com>
> > wrote:
> >
> > > I'm not exactly sure how preload_app works, but I suspect your app is
> > > lazy-loading a number of Ruby libraries while handling the first few
> > > requests that weren't automatically loaded during the preload process.
> > >
> > > Eric, your thoughts?
>
> (top-posting corrected)
>
> Yeah, preload_app won't help startup speed if much of the app is
> autoloaded.
>
> Sarkis: which Ruby version are you running?  IIRC, 1.9.2 had terrible
> startup performance compared to 1.9.3 and later in case you're stuck on
> 1.9.2
>
> > That does make sense - I was looking at another suggestion from a user
> here
> > (Braulio) of running a "warmup" using rack MockRequest:
> > https://gist.github.com/brauliobo/11298486#file-unicorn-conf-rb-L77
> >
> > The only issue I am having with the above solution is it is happening in
> > the before_fork block - shouldn't I warmup the connection in after_fork?
>
> If preload_app is true, you can warmup in before_fork; otherwise it
> needs to be after_fork.
>
> > If
> > I follow the above gist properly it warms up the server with the old
> > activerecord base connection and then its turned off, then turned back on
> > in after_fork. I think I am not understanding the sequence of events
> > there...
>
> With preload_app and warmup, you need to ensure any stream connections
> (DB, memcached, redis, etc..) do not get shared between processes, so
> it's standard practice to disconnect in the parent and reconnect in the
> child.
>
> > If this is the case, I should warmup and also check/kill the old
> > master in the after_fork block after the new db, redis, neo4j connections
> > are all created. Thoughts?
>
> I've been leaving killing the master outside of the unicorn hooks
> and doing it as a separate step; seemed too fragile to do it in
> hooks from my perspective.
>



-- 
*Sarkis Varozian*
svarozian@gmail.com