Re: Repacking many disconnected blobs

From: Keith Packard <keithp@keithp.com>
Date: Jun 14, 2006, 21:05 UTC
Message-ID: <1150319115.30681.54.camel@neko.keithp.com>
In-Reply-To: <Pine.LNX.4.64.0606141514000.2703@localhost.localdomain>

On Wed, 2006-06-14 at 15:25 -0400, Nicolas Pitre wrote:

Show 5 quoted lines

> The only advantage of feeding object names from latest to oldest has to 
> do with the delta direction.  In doing so the delta are backward such 
> that objects with deeper delta chain are further back in history and 
> this is what you want in the final pack for faster access to the latest 
> revision.

Ok, so I'm feeding them from latest to oldest along each branch, which optimizes only the 'master' branch, leaving other branches much further down in the data file. That should mean repacking will help a lot for repositories with many active branches.

> In that case it 
> might be preferable that the reuse of already deltified data is made of 
> backward delta which is the reason you might consider feeding object in 
> the prefered order up front.

Hmm. As I'm deltafying along branches, the delta data should actually be fairly good; the only 'bad' result will be the sub-optimal object ordering in the pack files. I'll experiment with some larger trees to see how much additional savings the various repack options yield.

-- 
keith.packard@intel.com