Re: [FYI] very large text files and their problems.

From: Ian Kumlien <pomac@vapor.com>
Date: Feb 22, 2012, 18:39 UTC
Message-ID: <1329935980.23912.5.camel@pi>

Seems like i ruined my dovecot config in a recent upgrade - which also affected my mail... =/

Anyway, it's all fixed now.

from: Nguyen Thai Ngoc Duy <pclouds () gmail ! com>

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> On Wed, Feb 22, 2012 at 10:49 PM, Ian Kumlien <pomac@vapor.com> wrote:
> > Hi,
> >
> > We just saw a interesting issue, git compressed a ~3.4 gb project to
> ~57 mb.
> 
> How big are those files? How many of them? How often do they change?

This is the initial check in, one of the files is a 3.3 gb text file.

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> > But when we tried to clone it on a big machine we got:
> >
> > fatal: Out of memory, malloc failed (tried to allocate
> > 18446744072724798634 bytes)
> >
> > This is already fixed in the 1.7.10 mainline - but it also seems
> like
> 
> Does 1.7.9 have this problem?

I've tested with 1.7.9.1, haven't downgraded to test with 1.7.9...

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> > git needs to have atleast the same ammount of memory as the largest
> > file free... Couldn't this be worked around?
> >
> > On a (32 bit) machine with 4GB memory - results in:
> > fatal: Out of memory, malloc failed (tried to allocate 3310214313
> bytes)
> >
> > (and i see how this could be a problem, but couldn't it be
> mitigated? or
> > is it bydesign and intended behaviour?)
> 
> I think that it's delta resolving that hogs all your memory. If your
> files are smaller than 512M, try lower core.bigFileThreshold. The
> topic jc/split-blob, which stores a big file are several smaller
> pieces, might solve your problem. Unfortunately the topic is not
> complete yet.

the problem here is that there is one file that is exactly: 3310214313 bytes, so it should all be one "blob".

split-blob would be really interesting for several reasons though =)

> -- 
> Duy
> --

-- 
Ian Kumlien  -- http://demius.net || http://pomac.netswarm.net