From: Marius Storm-Olsen <mstormo@gmail.com>
To: git@vger.kernel.org
Subject: Delta compression not so effective
Date: Wed, 1 Mar 2017 07:51:18 -0600 [thread overview]
Message-ID: <4d2a1852-8c84-2869-78ad-3c863f6dcaf7@gmail.com> (raw)
I have just converted an SVN repo to Git (using SubGit), where I feel
delta compression has let me down :)
Suffice it to say, this is a "traditional" SVN repo, with an extern/
blown out of proportion with many binary check-ins. BUT, even still, I
would expect Git's delta compression to be quite effective, compared to
the compression present in SVN. In this case however, the Git repo ends
up being 46% larger than the SVN DB.
Details - SVN:
Commits: 32988
DB (server) size: 139GB
Branches: 103
Tags: 1088
Details - Git:
$ git count-objects -v
count: 0
size: 0
in-pack: 666515
packs: 1
size-pack: 211933109
prune-packable: 0
garbage: 0
size-garbage: 0
$ du -sh .
203G .
$ java -jar ~/sources/bfg/bfg.jar --delete-folders extern
--no-blob-protection && \
git reflog expire --expire=now --all && \
git gc --prune=now --aggressive
$ git count-objects -v
count: 0
size: 0
in-pack: 495070
packs: 1
size-pack: 5765365
prune-packable: 0
garbage: 0
size-garbage: 0
$ du -sh .
5.6G .
When first importing, I disabled gc to avoid any repacking until
completed. When done importing, there was 209GB of all loose objects
(~670k files). With the hopes of quick consolidation, I did a
git -c gc.autoDetach=0 -c gc.reflogExpire=0 \
-c gc.reflogExpireUnreachable=0 -c gc.rerereresolved=0 \
-c gc.rerereunresolved=0 -c gc.pruneExpire=now \
gc --prune
which brought it down to 206GB in a single pack. I then ran
git repack -a -d -F --window=350 --depth=250
which took it down to 203GB, where I'm at right now.
However, this is still miles away from the 139GB in SVN's DB.
Any ideas what's going on, and why my results are so terrible, compared
to SVN?
Thanks!
--
.marius
next reply other threads:[~2017-03-01 13:59 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-01 13:51 Marius Storm-Olsen [this message]
2017-03-01 16:06 ` Delta compression not so effective 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
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