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>
Eric,
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.
next prev parent 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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