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From: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
To: git@vger.kernel.org
Subject: protocol v2: More data transmitted between client and server since v2.20.0
Date: Mon, 21 Jan 2019 03:00:38 +0530	[thread overview]
Message-ID: <d8ef0c1e5f48952c6190672bc26244a02b8e9bcd.camel@gmail.com> (raw)

Hi all,

I recently came across a blog[1] about how protocol v2 speeds up the
transfer between the client and the server. It states that the amount
of data transmitted between the client and the server is less when
using the protocol v2.

To demonstrate the difference between v0 and v2 two commands were
mentioned in the blog. The results hold true for me when I test using
Git v2.18.1. The commands given there worked as mentioned in the blog
until Git v2.18.1. But when I run the same commands using Git v2.19.2
or the one I built from source in the 'next' branch (at aa96b0ce6b).
I'm not sure why this is the case. Some observations below:

Protocol v0
===========
# Git version: 2.18.1
$ GIT_TRACE_PACKET=1 git -c protocol.version=0 ls-remote git@gitlab.com:gitlab-org/gitlab-ce.git master 2>git_protocol_0_git_2.18.1_stderr.txt
d4d4ebadfb373518013382560b1f505eb6217f13	refs/heads/master

$ wc -l git_protocol_0_git_2.18.1_stderr.txt
36848 git_protocol_0_git_2.18.1_stderr.txt


# Git version: 2.19.0
$ GIT_TRACE_PACKET=1 git -c protocol.version=0 ls-remote git@gitlab.com:gitlab-org/gitlab-ce.git master 2>git_protocol_0_git_2.19.0_stderr.txt
d4d4ebadfb373518013382560b1f505eb6217f13	refs/heads/master

$ wc -l git_protocol_0_git_2.19.0_stderr.txt 
36848 git_protocol_0_git_2.19.0_stderr.txt


# Git version: 2.20.0
$ GIT_TRACE_PACKET=1 git -c protocol.version=0 ls-remote git@gitlab.com:gitlab-org/gitlab-ce.git master 2>git_protocol_0_git_2.20.0_stderr.txt
d4d4ebadfb373518013382560b1f505eb6217f13	refs/heads/master

$ wc -l git_protocol_0_git_2.20.0_stderr.txt 
36848 git_protocol_0_git_2.20.0_stderr.txt


# Git version: 2.20.1.495.gaa96b0ce6b
$ GIT_TRACE_PACKET=1 git -c protocol.version=0 ls-remote git@gitlab.com:gitlab-org/gitlab-ce.git master 2>git_protocol_0_git_2.20.1-source_stderr.txt
d4d4ebadfb373518013382560b1f505eb6217f13	refs/heads/master

$ wc -l git_protocol_0_git_2.20.1-source_stderr.txt 
36848 git_protocol_0_git_2.20.1-source_stderr.txt 


Protocol v2
===========
# Git version: 2.18.1
$ GIT_TRACE_PACKET=1 git -c protocol.version=2 ls-remote git@gitlab.com:gitlab-org/gitlab-ce.git master 2>git_protocol_2_git_2.18.1_stderr.txt
d4d4ebadfb373518013382560b1f505eb6217f13	refs/heads/master

$ wc -l git_protocol_2_git_2.18.1_stderr.txt
22 git_protocol_2_git_2.18.1_stderr.txt


# Git version: 2.19.0
$ GIT_TRACE_PACKET=1 git -c protocol.version=2 ls-remote git@gitlab.com:gitlab-org/gitlab-ce.git master 2>git_protocol_2_git_2.19.0_stderr.txt
d4d4ebadfb373518013382560b1f505eb6217f13	refs/heads/master

$ wc -l
22 git_protocol_2_git_2.19.0_stderr.txt


# Git version: 2.20.0
$ GIT_TRACE_PACKET=1 git -c protocol.version=2 ls-remote git@gitlab.com:gitlab-org/gitlab-ce.git master 2>git_protocol_2_git_2.20.0_stderr.txt
d4d4ebadfb373518013382560b1f505eb6217f13	refs/heads/master
04845fdeae75ba5de7c93992a5d55663edf647e0	refs/remotes/remote_mirror_630f74462b3b08a952486da866d5e702/master
04845fdeae75ba5de7c93992a5d55663edf647e0	refs/remotes/remote_mirror_655ad545056a2ad17e7ebc5461a986e4/master
d4d4ebadfb373518013382560b1f505eb6217f13	refs/remotes/remote_mirror_d612bbe5bee4fbc624df371bc7caa759/master

$ wc -l git_protocol_2_git_2.20.0_stderr.txt 
160971 git_protocol_2_git_2.20.0_stderr.txt


# Git version: 2.20.1.495.gaa96b0ce6b
$ GIT_TRACE_PACKET=1 git -c protocol.version=2 ls-remote git@gitlab.com:gitlab-org/gitlab-ce.git master 2>git_protocol_2_git_2.20.1-source_stderr.txt
d4d4ebadfb373518013382560b1f505eb6217f13	refs/heads/master
04845fdeae75ba5de7c93992a5d55663edf647e0	refs/remotes/remote_mirror_630f74462b3b08a952486da866d5e702/master
04845fdeae75ba5de7c93992a5d55663edf647e0	refs/remotes/remote_mirror_655ad545056a2ad17e7ebc5461a986e4/master
d4d4ebadfb373518013382560b1f505eb6217f13	refs/remotes/remote_mirror_d612bbe5bee4fbc624df371bc7caa759/master

$ wc -l git_protocol_2_git_2.20.1-source_stderr.txt
160971 git_protocol_2_git_2.20.1-source_stderr.txt


Also, note that there are more refs printed when using v2 which is
spooky too. I thought of running a bisect to find the actual culprit
but wanted to know if this was *actually* an issue or not? Any
thoughts?


References
==========
[1]: 
https://about.gitlab.com/2018/12/10/git-protocol-v2-enabled-for-ssh-on-gitlab-dot-com/

--
Sivaraam


             reply	other threads:[~2019-01-21  8:28 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-20 21:30 Kaartic Sivaraam [this message]
2019-01-20 21:35 ` protocol v2: More data transmitted between client and server since v2.20.0 Kaartic Sivaraam
  -- strict thread matches above, loose matches on Subject: below --
2019-01-21  6:15 Kaartic Sivaraam
2019-01-28 21:23 ` Jeff King
2019-02-02 18:01   ` Kaartic.Sivaraam

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