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From: Steffen Prohaska <prohaska@zib.de>
To: Junio C Hamano <gitster@pobox.com>
Cc: "Andreas Ericsson" <ae@op5.se>,
	"Ævar Arnfjörð Bjarmason" <avarab@gmail.com>,
	"Git Mailing List" <git@vger.kernel.org>,
	"Jeff King" <peff@peff.net>,
	spearce@spearce.org,
	"Johannes Schindelin" <Johannes.Schindelin@gmx.de>
Subject: Re: Is anyone working on a next-gen Git protocol?
Date: Wed, 10 Oct 2012 21:13:37 +0200	[thread overview]
Message-ID: <035A66D9-FAF0-48EE-B161-7D0CAD92F2FB@zib.de> (raw)
In-Reply-To: <7vtxu5lyjr.fsf@alter.siamese.dyndns.org>

On Oct 8, 2012, at 6:27 PM, Junio C Hamano wrote:

> Once we go into "want/have" phase, I do not think there is a need
> for fundamental change in the protocol (by this, I am not counting a
> change to send "have"s sparsely and possibly backtracking to bisect
> history, etc. as "fundamental").

I've recently discovered that the current protocol can be amazingly
inefficient when it comes to transferring binary objects.  Assuming two
repositories that are in sync.  After a 'git checkout --orphan && git
commit', a subsequent transfers sends all the blobs attached to the new
commit, although the other side already has all the blobs.

This behavior is especially annoying when (mis)using git to store binary
files.  I was thinking for a while that it might be a reasonable idea to
store binary files in a submodule and frequently cut the history in
order to save space.  The history would have little value anyway, since
diff and merge don't make much sense with binary files.

Eventually, I abandoned the idea due to the current behavior of the
protocol.  I had expected that git would be smarter and behave more like
rsync, for example, by skipping big blobs as soon as it recognizes that
they are already available at both sides.

Maybe the new protocol could include an optimization for the described
case.  I don't know whether this would be a fundamental change.

    Steffen

  reply	other threads:[~2012-10-10 19:14 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-07 19:57 Is anyone working on a next-gen Git protocol? Ævar Arnfjörð Bjarmason
2012-10-07 20:22 ` Ilari Liusvaara
2012-10-07 22:08 ` Jeff King
2012-10-07 22:31 ` Junio C Hamano
2012-10-22  4:59   ` Junio C Hamano
2012-10-08  9:05 ` Andreas Ericsson
2012-10-08 16:27   ` Junio C Hamano
2012-10-10 19:13     ` Steffen Prohaska [this message]
2012-10-10 20:46       ` Junio C Hamano
2012-10-10 22:32         ` Philip Oakley
2012-10-11  1:44         ` Nguyen Thai Ngoc Duy
2012-10-11  3:08           ` Shawn Pearce

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