From: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
To: Jeff King <peff@peff.net>
Cc: "Martin Fick" <mfick@codeaurora.org>,
"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
"Derrick Stolee" <stolee@gmail.com>,
"Lars Schneider" <larsxschneider@gmail.com>,
git <git@vger.kernel.org>, "Duy Nguyen" <pclouds@gmail.com>
Subject: Re: worktrees vs. alternates
Date: Wed, 16 May 2018 16:02:53 -0400 [thread overview]
Message-ID: <5156717b-6fc9-b792-dfa4-1ba48ac50333@linuxfoundation.org> (raw)
In-Reply-To: <20180516193744.GA4036@sigill.intra.peff.net>
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On 05/16/18 15:37, Jeff King wrote:
> Yes, that's pretty close to what we do at GitHub. Before doing any
> repacking in the mother repo, we actually do the equivalent of:
>
> git fetch --prune ../$id.git +refs/*:refs/remotes/$id/*
> git repack -Adl
>
> from each child to pick up any new objects to de-duplicate (our "mother"
> repos are not real repos at all, but just big shared-object stores).
Yes, I keep thinking of doing the same, too -- instead of using
torvalds/linux.git for alternates, have an internal repo where objects
from all forks are stored. This conversation may finally give me the
shove I've been needing to poke at this. :)
Is your delta-islands patch heading into upstream, or is that something
that's going to remain external?
> I say "equivalent" because those commands can actually be a bit slow. So
> we do some hacky tricks like directly moving objects in the filesystem.
>
> In theory the fetch means that it's safe to actually prune in the mother
> repo, but in practice there are still races. They don't come up often,
> but if you have enough repositories, they do eventually. :)
I feel like a whitepaper on "how we deal with bajillions of forks at
GitHub" would be nice. :) I was previously told that it's unlikely such
paper could be written due to so many custom-built things at GH, but I
would be very happy if that turned out not to be the case.
Best,
--
Konstantin Ryabitsev
Director, IT Infrastructure Security
The Linux Foundation
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next prev parent reply other threads:[~2018-05-16 20:03 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-16 8:13 worktrees vs. alternates Lars Schneider
2018-05-16 9:29 ` Ævar Arnfjörð Bjarmason
2018-05-16 9:42 ` Robert P. J. Day
2018-05-16 11:07 ` Ævar Arnfjörð Bjarmason
2018-05-16 9:51 ` Lars Schneider
2018-05-16 10:33 ` Ævar Arnfjörð Bjarmason
2018-05-16 13:02 ` Derrick Stolee
2018-05-16 14:58 ` Konstantin Ryabitsev
2018-05-16 15:34 ` Ævar Arnfjörð Bjarmason
2018-05-16 15:49 ` Konstantin Ryabitsev
2018-05-16 17:54 ` Ævar Arnfjörð Bjarmason
2018-05-16 17:14 ` Martin Fick
2018-05-16 17:41 ` Konstantin Ryabitsev
2018-05-16 18:02 ` Ævar Arnfjörð Bjarmason
2018-05-16 18:12 ` Konstantin Ryabitsev
2018-05-16 18:26 ` Martin Fick
2018-05-16 19:01 ` Konstantin Ryabitsev
2018-05-16 19:03 ` Martin Fick
2018-05-16 19:11 ` Konstantin Ryabitsev
2018-05-16 19:18 ` Martin Fick
2018-05-16 19:23 ` Jeff King
2018-05-16 19:29 ` Konstantin Ryabitsev
2018-05-16 19:37 ` Jeff King
2018-05-16 19:40 ` Martin Fick
2018-05-16 20:06 ` Jeff King
2018-05-16 20:43 ` Martin Fick
2018-05-16 20:02 ` Konstantin Ryabitsev [this message]
2018-05-16 20:17 ` Jeff King
2018-05-17 0:43 ` Sitaram Chamarty
2018-05-17 3:31 ` Jeff King
2018-05-19 5:45 ` Duy Nguyen
2018-05-16 19:14 ` Jeff King
2018-05-16 21:18 ` Stefan Beller
2018-05-16 23:45 ` Jeff King
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