Re: [PATCH] add the ability to create and retrieve delta objects

[Nicolas Pitre <nico@cam.org>]

On Wed, 4 May 2005, Chris Mason wrote:

> On Wednesday 04 May 2005 17:47, Geert Bosch wrote:
> >  From your tests it would seem that the zdelta version is the only one
> > to provide a uniform improvement over plain git. As it also seems the
> > simplest approach, I wonder why the consensus is that using xdiff
> > would be better?
> 
> zdelta seems to be a research project.  It does compress better than the xdiff 
> lib, but the speed improvements against xdiff(1) are probably because the 
> resulting tree is smaller.  I favor the xdiff code because it's so much 
> smaller, and seems easier for us to maintain.

Yep.  And compression can be improved without changing de decompressor 
since the decompressor is only a replay of what the compressor found to 
be redundent.  That redundency searching can probably be improved wrt to 
the current code.  And FRankly considering about 300 lines of code to 
create a delta and 60 lines to expand it is hard to beat maintenance 
wise.

> For performance, there's still quite a bit of tuning that can be done in terms 
> of when and how we delta.

Indeed.


Nicolas