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From: Charles Oliver Nutter <headius@headius.com>
To: rack-devel@googlegroups.com
Subject: Re: Not cleaning up tempfiles for multipart?
Date: Sun, 7 Mar 2010 08:27:55 -0600	[thread overview]
Message-ID: <f04d2211003070627i79e7368fl98e7cd947eda156@mail.gmail.com> (raw)
In-Reply-To: <20100306075548.GB6474@dcvr.yhbt.net>

On Sat, Mar 6, 2010 at 1:55 AM, Eric Wong <normalperson@yhbt.net> wrote:
> Charles Oliver Nutter <headius@headius.com> wrote:
>> If I'm correct, this is a bug. Tempfiles should not be relied upon to
>> clean themselves up in response to GC, since you don't know when GC
>> will fire...
> Why not?  Tempfiles are objects, too.  It's perfectly reasonable
> to let GC clean them up like any other object.
> I don't know why RewindableInput is monkeying with Tempfile internals,
> though.

It's roundly considered by every programming language community in the
world to be *really* bad form to let GC clean up IO. There's tons of
reasons for this:

* GC may not run as soon as you like, causing you to hold IO resources
too long (and under heavy load, potentially use up all descriptors for
a process)
* On some systems, old objects get promoted to heaps that are only
rarely collected, resulting in them potentially never GCing (or only
GCing extremely rarely)
* There's no reason you *shouldn't* be able to close resources when
they're no longer used. In this case, close any files opened for a
give request once the request has been processed (async libraries
using those files should expect them to be closed and deal with that

Bug-finding tools for several languages flag this sort of behavior as
a high-priority bug. Languages like Go, C#, and Java have or are
adding features to help guarantee you never do this. It's pretty much
universally frowned upon.

When I tweeted about Rubyists leaving IO objects to be cleaned up or
closed by GC, *everyone* agreed that it's a bug in the code, and that
nobody should ever rely on GC to release File/IO resources.

What more can I say? :)

- Charlie

  parent reply	other threads:[~2010-03-07 14:28 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-05 14:40 Charles Oliver Nutter
2010-03-05 14:47 ` Charles Oliver Nutter
2010-03-05 14:48   ` Charles Oliver Nutter
2010-03-06 10:20   ` Hongli Lai
2010-03-07 14:25     ` Charles Oliver Nutter
2010-03-06  7:55 ` Eric Wong
2010-03-06 10:25   ` Hongli Lai
2010-03-07 14:34     ` Charles Oliver Nutter
2010-03-08  0:22       ` Eric Wong
2010-03-08  1:12         ` Eric Wong
2010-03-17 15:41           ` Charles Oliver Nutter
2010-03-18  9:54             ` Eric Wong
2014-01-06 22:45               ` Wojtek Kruszewski
2014-02-11 21:05                 ` Eric Wong
2014-03-27 21:40                   ` Lenny Marks
2010-03-07 23:53     ` Eric Wong
2010-03-08 11:26       ` Hongli Lai
2010-03-08 11:30         ` Hongli Lai
2010-03-08 14:33           ` Randy Fischer
2010-03-08 14:43           ` Charles Oliver Nutter
2010-03-08 14:49             ` James Tucker
2010-03-17  2:37           ` Eric Wong
2010-03-08 13:22         ` Charles Oliver Nutter
2010-03-08 14:42         ` James Tucker
2010-03-08 17:24           ` Hongli Lai
2010-03-09  7:43             ` Charles Oliver Nutter
2010-03-08 10:05     ` James Tucker
2010-03-07 14:27   ` Charles Oliver Nutter [this message]
2010-03-08  0:18     ` Eric Wong
2010-03-08 10:07       ` James Tucker

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