Re: git and binary files

From: Petko Manolov <petkan@nucleusys.com>
Date: Jan 16, 2008, 16:06 UTC
Message-ID: <alpine.DEB.1.00.0801161802370.5260@bender.nucleusys.com>
In-Reply-To: <alpine.LFD.1.00.0801161056500.25841@xanadu.home>

On Wed, 16 Jan 2008, Nicolas Pitre wrote:

Show 28 quoted lines

> On Wed, 16 Jan 2008, Petko Manolov wrote:
>
>> On Wed, 16 Jan 2008, Nicolas Pitre wrote:
>>
>>> On Wed, 16 Jan 2008, Petko Manolov wrote:
>>>
>>>> On Wed, 16 Jan 2008, Jakub Narebski wrote:
>>>>
>>>>> Petko Manolov wrote:
>>>>>>
>>>>>> Unfortunately this is not the case.  These binary blobs are already
>>>>>> compressed and/or encrypted and adding even a few bytes ends up
>>>>>> storing
>>>>>> new version in full size.
>>>>>
>>>>> Can't you store them uncompressed?
>>>>
>>>> Not really, but i can convert them into ascii format and store only the
>>>> delta.
>>>
>>> If you don't have the original uncompressed unencrypted file, what will
>>> converting them to ascii actually give you?
>>
>> I hope that in the case of incremental changes (0 to 5MB file is the same,
>> last 64KB are actually new) the delta will be small and should be able to
>> compress well.
>>
>> This won't work for random changes along the length of the whole file.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> But my question remains.
>
> If you cannot create good deltas out of your binary files, converting
> those binaries into ascii will do nothing to compression performance.

I did agree with you above.  Binary or ascii it doesn't matter.

The experiments so far shows that git is doing a good job finding deltas in binary files. This may be a solution for certain part of my files...

 		Petko