From: Nicolas Pitre <nico@cam.org>
Date: Tue, 03 May 2005 12:51:03 GMT
Subject: Re: [PATCH] add the ability to create and retrieve delta objects
Message-ID: <Pine.LNX.4.62.0505030847140.14033@localhost.localdomain>
In-Reply-To: <200505030724.57827.mason@suse.com>

On Tue, 3 May 2005, Chris Mason wrote:

> This looks much nicer than using zdelta, I'll try switching my packed item to 
> your delta generator later this week.  Some quick and dirty space numbers to 
> show why we need to pack the files together:
> 
> On the full import of all the bk->cvs changesets, the average file size 
> in .git is 4074 bytes.  73% of the files are 4096 bytes or smaller.
> 
> This means that of the 2.5GB the .git directory consumes, about 1GB is taken 
> up by files under 4k where deltas won't save space.  If the remaining files 
> could be delta compressed down to less than 4k, they would still take up 
> around 400MB on disk.

Sure.  However it helps for history backups and network transfer.

However if the delta compression and packed storage can remain as 
decoupled as possible from each other this is good for flexibility.


Nicolas