Re: [PATCH] pack-objects: use of version 3 delta is now optional.

From: Nicolas Pitre <nico@cam.org>
Date: Oct 16, 2006, 13:43 UTC
Message-ID: <Pine.LNX.4.64.0610160929450.17085@xanadu.home>
In-Reply-To: <Pine.LNX.4.64.0610151150530.3952@g5.osdl.org>

On Sun, 15 Oct 2006, Linus Torvalds wrote:

Show 15 quoted lines

> 
> 
> On Sun, 15 Oct 2006, Junio C Hamano wrote:
> > 
> > I think that is sensible.  I also was thinking that we should
> > call the current one packv3 and the one with delta-base-offset
> > packv4.
> 
> Quite frankly, I wonder if the pure "copy size extension" (aka "v3") thing 
> is really worth it at all. 
> 
> I mean, seriously, how much does it buy us? A couple of bytes per every 
> 64kB of delta copied? And the downside is that you can't re-use the deltas 
> with old clients and/or you have to re-create a "v2" delta at run-time 
> from a v3 delta by inflating, fixing and deflating it.

Right. This is why I suggested Junio to just drop it for now. Let's just wait some more until this is just not an issue any longer, say in a year from now when all major distributions have switched to a GIT version that can read V3.

If until then we find the saving really worth the backward compatibility v3-to-v2 conversion then we could reconsider. But I don't think it is worth it just yet.

In the mean time, if Junio adds the patch I posted yesterday advertising the pack version capability over the native protocol then it'll help us make things forward compatible if ever we decide to go with generating packs v3 sooner.

Nicolas