From: Marius Storm-Olsen <mstormo@gmail.com>
To: Martin Langhoff <martin.langhoff@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>
Subject: Re: Delta compression not so effective
Date: Wed, 1 Mar 2017 17:59:30 -0600 [thread overview]
Message-ID: <6a72bfd4-5032-5e40-5c6d-8b77ca5ae775@gmail.com> (raw)
In-Reply-To: <CACPiFC+=ZpHT=xh7Y8f68BcXxNYx8EFJfzqqG2ub4NL=uREu7g@mail.gmail.com>
On 3/1/2017 14:19, Martin Langhoff wrote:
> On Wed, Mar 1, 2017 at 8:51 AM, Marius Storm-Olsen <mstormo@gmail.com> wrote:
>> BUT, even still, I would expect Git's delta compression to be quite effective, compared to the compression present in SVN.
>
> jar files are zipfiles. They don't delta in any useful form, and in
> fact they differ even if they contain identical binary files inside.
If you look through the initial post, you'll see that the jar in
question is in fact a tool (BFG) by Roberto Tyley, which is basically
git filter-branch on steroids. I used it to quickly filter out the
extern/ folder, just to prove most of the original size stems from that
particular folder. That's all.
The repo does not contain zip or jar files. A few images and other
compressed formats (except a few 100MBs of proprietary files, which
never change), but nothing unusual.
>> Commits: 32988
>> DB (server) size: 139GB
>
> Are you certain of the on-disk storage at the SVN server? Ideally,
> you've taken the size with a low-level tool like `du -sh
> /path/to/SVNRoot`.
139GB is from 'du -sh' on the SVN server. I imported (via SubGit)
directly from the (hotcopied) SVN folder on the server. So true SVN size.
> Even with no delta compression (as per Junio and Linus' discussion),
> based on past experience importing jar/wars/binaries from SVN into
> git... I'd expect git's worst case to be on-par with SVN, perhaps ~5%
> larger due to compression headers on uncompressible data.
Yes, I was expecting a Git repo <139GB, but like Linus mentioned,
something must be knocking the delta search off its feet, so it bails
out. Loose object -> 'hard' repack didn't show that much difference.
Thanks!
--
.marius
prev parent reply other threads:[~2017-03-02 0:06 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-01 13:51 Delta compression not so effective Marius Storm-Olsen
2017-03-01 16:06 ` Junio C Hamano
2017-03-01 16:17 ` Junio C Hamano
2017-03-01 17:36 ` Linus Torvalds
2017-03-01 17:57 ` Marius Storm-Olsen
2017-03-01 18:30 ` Linus Torvalds
2017-03-01 21:08 ` Martin Langhoff
2017-03-02 0:12 ` Marius Storm-Olsen
2017-03-02 0:43 ` Linus Torvalds
2017-03-04 8:27 ` Marius Storm-Olsen
2017-03-06 1:14 ` Linus Torvalds
2017-03-06 13:36 ` Marius Storm-Olsen
2017-03-07 9:07 ` Thomas Braun
2017-03-01 20:19 ` Martin Langhoff
2017-03-01 23:59 ` Marius Storm-Olsen [this message]
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