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RE: sync bug -> corrupted proxy repo

From: Giulio Troccoli <Giulio.Troccoli_at_uk.linedata.com>
Date: Wed, 13 Jan 2010 13:27:29 +0000

>

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-----Original Message-----

> From: Jon Foster [mailto:Jon.Foster_at_cabot.co.uk]
> Sent: 13 January 2010 13:13
> To: Andersen, Krista; users_at_subversion.apache.org
> Cc: ssi-svn_admin
> Subject: RE: sync bug -> corrupted proxy repo
>
> Hi,
>
> Andersen, Krista [mailto:Krista.Andersen_at_itg.com] wrote:
> > Twice I have seen one of my proxy repositories become
> corrupted due to
> > an apparent bug in the svnsync sync process. Has anyone else seen
> > this type of behavior from Subversion?
>
> This is probably caused by issue 3546 [1][2]. This is a race
> condition - if you have several sync processes running at the
> same time then the mirror can get corrupted. You had three
> commits which were 1 second apart, so your hook script
> started 3 copies of svnsync within 2 seconds. I think this
> is the first practical report of this bug; previous
> discussion was theoretical.
>
> > Here is a comparison the output of the svn log -v for the offending
> > revisions (324,325) on both the corrupted and non-corrupted proxy
> > repo.
>
> It looks like rev 323 got mirrored twice (as mirror revs 323
> and 324), then rev 324 was mirrored (as mirror rev 325).
>
> > I am a bit concerned about the stability of Subversion
> since this is
> > the second time in two months that I have had to fix this issue.
> > Is there a patch or something to prevent this in the future?
>
> Suggested workaround: Change your hook scripts to use the
> lockf or lockfile tools[3] to ensure that only one instance
> of svnsync runs at once.

Is it not the case that a svn commit cannot start before the post-commit hooks has finished? I am asking becuase I will be implementing a DR system using svnsync, but I am not planning to let the post-commit finish before svnsync has finished (I don't care if it takes a bit longer, I can cope with that and with my users).

Giulio
Received on 2010-01-13 14:28:06 CET

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