Re: git repository size / compression
- From
- neubyr <neubyr@gmail.com>
- Date
- Sep 9, 2011, 14:04 UTC
- Message-ID
- <CALFxCvxmPN_O_3xpkrGUYtdkVfz5nr7eaucMrAYQ3uvi820FBg@mail.gmail.com>
- In-Reply-To
- <1315556595.2019.11.camel@bee.lab.cmartin.tk>
On Fri, Sep 9, 2011 at 3:23 AM, Carlos Martín Nieto <cmn@elego.de> wrote:
Show 33 quoted lines
> On Thu, 2011-09-08 at 21:37 -0500, neubyr wrote:
>> I have a test git repository with just two files in it. One of the
>> file in it has a set of two lines that is repeated n times.
>> e.g.:
>> {{{
>> $ for i in {1..5}; do cat ./lexico.txt >> lexico1.txt && cat
>> ./lexico.txt >> lexico1.txt && mv ./lexico1.txt ./lexico.txt; done
>> }}}
>>
>
> So you've just created some data that can be compressed quite
> efficiently.
>
>> I ran above command few times and performed commit after each run. Now
>> disk usage of this repository directory is mentioned below. The 419M
>> is working directory size and 2.7M is git repository/database size.
>>
>> {{{
>> $ du -h -d 1 .
>> 2.7M ./.git
>> 419M .
>>
>> }}}
>>
>> Is it because of the compression performed by git before storing data
>> (or before sending commit)??
>>
>
> Yes. Git stores its objects (the commit, the snapshot of the files,
> etc.) compressed. When these objects are stored in a pack, the size can
> be further reduced by storing some objects as deltas which describe the
> difference between itself and some other object in the object-db.
>Does git store deltas for some files? I thought it uses snapshots (exact copy of staged files) only.
Show 36 quoted lines
>> Following were results with subversion:
>>
>> Subversion client (redundant(?) copy exists in .svn/text-base/
>> directory, hence double size in client):
>> {{{
>> $ du -h -d 1
>> 416M ./.svn
>> 832M .
>> }}}
>
> Subversion stores the "pristines" (which is the status of the files in
> the latest revision) inside the .svn directory. I wouldn't call this
> copy redundant, though, as it allows you to run diff locally. The
> pristines are stored uncompressed, which is why you half of the space is
> taken up by the .svn directory.
>
>>
>> Subversion repo/server:
>> {{{
>> $ du -h -d 1
>> 12K ./conf
>> 1.2M ./db
>> 36K ./hooks
>> 8.0K ./locks
>> 1.2M .
>> }}}
>
> I don't know how the repository is stored in Subversion, but it may also
> be compressed. You may be able to reduced your git repository size by
> (re)generating packs with 'git repack' and doing some cleanups with 'git
> gc', but the repository size is not often a concern.
>
> cmn
>
>
>that's helpful. thanks.
-- neuby.r