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From: "Lin Jen-Shin (godfat)" <godfat@godfat.org>
To: yahns-public@yhbt.net
Cc: wildjcrt@gmail.com
Subject: What would happen if a worker thread died?
Date: Fri, 8 May 2015 20:20:13 +0800	[thread overview]
Message-ID: <CAA2_N1umJO12XH9r+JHnA6r=z=Mwp_PqOrdnW65oqW2K2-iAoQ@mail.gmail.com> (raw)

Hi,

We just tried running yahns on production, and would like to
give some feedback. Eventually we turned back to Unicorn,
but that's because apparently Rails, or to be specific,
ActiveRecord (4.1.10) is not thread safe and giving random
errors once in a while.

However, we're also trying to split out an API server which is
not running on Rails, therefore we should be able to use a
threaded server.

During the experiments, we found that whenever a worker
thread died due to LoadError raised from the application,
which is not a StandardError therefore was not rescued at all,
crashing the worker thread (assumed, not verified).

When this happened, the client just hanged forever with yahns.
Is there something we can do about this? Would yahns respawn
a new worker thread? Can we close the socket when this happen?

I am aware that yahns is *extremely sensitive to fatal bugs in the
applications it hosts*, so I am just curious.

For reference, Puma would immediately close the socket without
sending anything, and Unicorn would log the error backtrace and
kill the worker (If I read it correctly).

In this case, Unicorn helped me figure out what's happened.

Cheers,

             reply	other threads:[~2015-05-08 12:20 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-08 12:20 Lin Jen-Shin (godfat) [this message]
2015-05-08 17:03 ` What would happen if a worker thread died? Eric Wong
2015-05-08 17:36   ` Lin Jen-Shin (godfat)
2015-05-09  1:03     ` Eric Wong
2015-05-09  7:26       ` Lin Jen-Shin (godfat)
2015-05-09  8:47         ` Eric Wong
2015-05-09  9:03           ` [PATCH] worker threads log LoadError and SyntaxError, too Eric Wong
2015-05-09  9:06           ` What would happen if a worker thread died? Lin Jen-Shin (godfat)

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