From: David Lang <david@lang.hm>
To: Dennis Luehring <dl.soluz@gmx.net>
Cc: git@vger.kernel.org
Subject: Re: question about: Facebook makes Mercurial faster than Git
Date: Mon, 10 Mar 2014 03:13:45 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.02.1403100310080.25193@nftneq.ynat.uz> (raw)
In-Reply-To: <531D8ED9.7040305@gmx.net>
On Mon, 10 Mar 2014, Dennis Luehring wrote:
> according to these blog posts
>
> http://www.infoq.com/news/2014/01/facebook-scaling-hg
> https://code.facebook.com/posts/218678814984400/scaling-mercurial-at-facebook/
>
> mercurial "can" be faster then git
>
> but i don't found any reply from the git community if it is a real problem
> or if there a ongoing (maybe git 2.0) changes to compete better in this case
As I understand this, the biggest part of what happened is that Facebook made a
tweak to mercurial so that when it needs to know what files have changed in
their massive tree, their version asks their special storage array, while git
would have to look at it through the filesystem interface (by doing stat calls
on the directories and files to see if anything has changed)
In other words, unless you have a very high end storage system that can keep
track of such things for you, the Facebook 'fix' won't help you. And even if it
does have such a capability, unless you use the same storage system that
Facebook uses, you would have to port it to your class of device.
Now, in addition to this, they did some other tweaks and changes, but compared
to this status change, everything else is minor.
David Lang
next prev parent reply other threads:[~2014-03-10 10:14 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-10 10:07 question about: Facebook makes Mercurial faster than Git Dennis Luehring
2014-03-10 10:13 ` David Lang [this message]
2014-03-10 17:51 ` Ondřej Bílka
2014-03-10 17:56 ` David Lang
2014-03-10 20:22 ` Martin Langhoff
2014-03-11 14:23 ` Ondřej Bílka
2014-03-10 11:28 ` demerphq
2014-03-10 11:42 ` Dennis Luehring
2014-03-10 12:10 ` Johan Herland
2014-03-10 14:48 ` Michael Haggerty
2014-03-10 14:18 ` Karsten Blees
2014-03-14 12:58 ` Duy Nguyen
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