From: Eric Wong <e@80x24.org>
To: Tony Devlin <tonydevlin@gmail.com>
Cc: unicorn-public@bogomips.org, Daniel Condomitti <daniel@condomitti.com>
Subject: Re: Weird Unicorn Timeout Issues (Hibernation problem?)
Date: Wed, 6 Aug 2014 09:45:57 +0000 [thread overview]
Message-ID: <20140806094557.GA19766@dcvr.yhbt.net> (raw)
In-Reply-To: <CAKM1sPNRsES6H6ByK6bO9Djwa8WvYV6HJ-rEaHopRUYBVFfuhg@mail.gmail.com>
Tony Devlin <tonydevlin@gmail.com> wrote:
> pid 7825] write(14,
> "\0\373\0\0\6\0\0\0\0\0\21iB\376\377\377\377\377\377\377\377\1\0\0\0\0\0\0\0\v\0\0\0\3^Ca\201\0\0\0\0\0\0\376\377\377\377\377\377\377\377\22\0\0\0\376\377\377\377\377\377\377\377\r\0\0\0\376\377\377\377\377\377\377\377\376\377\377\377\377\377\377\377\0\0\0\0d\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\376\377\377\377\377\377\377\377\0\0\0\0\0\0\0\0\376\377\377\377\377\377\377\377\376\377\377\377\377\377\377\377\376\377\377\377\377\377\377\377\0\0\0\0\0\0\0\0\376\377\377\377\377\377\377\377\376\377\377\377\377\377\377\377\22select
> 1 from
> dual\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0",
> 251) = 251
> [pid 7825] read(14, <unfinished ...>
> [pid 7827] +++ killed by SIGKILL +++
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 9:45 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 [this message]
2014-08-06 14:05 ` Tony Devlin
2014-08-06 18:26 ` Daniel Condomitti
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