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From: Tony Devlin <tonydevlin@gmail.com>
To: Eric Wong <e@80x24.org>
Cc: unicorn-public@bogomips.org, Daniel Condomitti <daniel@condomitti.com>
Subject: Re: Weird Unicorn Timeout Issues (Hibernation problem?)
Date: Wed, 6 Aug 2014 10:05:02 -0400	[thread overview]
Message-ID: <CAKM1sPPsb24aNA-puN=E6aYn=RqAynMaNMBiGvWqHtyaFe4cew@mail.gmail.com> (raw)
In-Reply-To: <20140806094557.GA19766@dcvr.yhbt.net>


The problem is a firewall that sits between the servers and the database.
 It is an idle session timeout of 30 minutes, so it is silently killing the
connection.  I have reached out to our Network Engineering department but
they are saying they can not change that idle session timeout, nor create a
special rule to allow this connection to bypass that rule.

Currently, I setup a polling device that calls the applications URL every
20 minutes.  This causes the connection between the server and DB to
refresh it's idle timeout.  This is obviously a very hacky way to handle
it, so I am trying to look into AR and Oracle_Enhanced to see if they have
some sort of keepalive option for the database.  I thought it would work
with the reaping_frequency, but apparently that does not work out as I had
expected when you are not running in pools or a thread.  So I'm still on
the lookout for something to handle that.

On Wed, Aug 6, 2014 at 5:45 AM, Eric Wong <e@80x24.org> wrote:
> Any update?  It looks like your DB driver is not using/respecting any
> timeout at all[1].  It is bad to not have a timeout there.  There should
> be a way to set a timeout so you can at least tell the user the DB
> connection dropped or maybe get your app to disconnect+retry once.
> A better looking strace would be something like:
>     write(fd, ...); => success
>     (poll|select|ppoll) syscall ...
>     read(fd, ...); /* only if (poll|select|ppoll) was successful[2] */
> This goes for configuring all connections/services for any app.
> [1] or if it's relying on SO_RCVTIMEO socket option(rare), that's set
>     way too high.  Any timeout set for any external connection should
>     be lower than the unicorn (last-resort) timeout feature.
> [2] any read() syscall after (poll|select|ppoll) should be non-blocking,
>     because (poll|select|ppoll) may spuriously wakeup.

  reply	other threads:[~2014-08-06 14:05 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-04 18:12 Weird Unicorn Timeout Issues (Hibernation problem?) Tony Devlin
2014-08-04 18:39 ` Eric Wong
2014-08-04 18:41   ` Kapil Israni
2014-08-04 18:48     ` Eric Wong
2014-08-04 18:45   ` Tony Devlin
2014-08-04 19:11     ` Eric Wong
2014-08-04 19:21       ` Tony Devlin
2014-08-04 19:45         ` Eric Wong
2014-08-04 20:06           ` Michael Fischer
2014-08-04 18:55   ` Daniel Condomitti
2014-08-04 19:34     ` Eric Wong
2014-08-04 20:24       ` Tony Devlin
2014-08-04 20:44         ` Eric Wong
2014-08-04 20:46           ` Eric Wong
2014-08-05 14:46             ` Tony Devlin
2014-08-06  9:45               ` Eric Wong
2014-08-06 14:05                 ` Tony Devlin [this message]
2014-08-06 18:26                   ` Daniel Condomitti

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