Re: [RFC] Cache negative delta pairs

From: Jeff King <peff@peff.net>
Date: 2006-06-30 07:37:28
On Thu, Jun 29, 2006 at 04:24:01PM -0400, Nicolas Pitre wrote:

> > Obviously the kernel repo is doing better, but x=500 is only 4 days ago.
> > Trying with --before=2.weeks.ago yields only 31505 matches.
> 
> What does this prove?  I fail to see the relation between those results 
> and a possible git-pack-objects improvement.

My point is that the window cache gets invalidated over time, whereas a
sha1 by sha1 cache doesn't.  However, the point is moot, as I think
Linus has come up with a much better solution.

> The negative delta cache concept is certainly attractive even for normal 
> repositories, especially for public servers, since when used in 
> conjonction with delta reuse it makes the creation of a pack basically 
> free.  So I think this idea really has merits, as long as the cache 
> remains small.

Yes, if you're talking about a situation in which you make many packs
for a given set of commits, then it does make more sense (what I was
really trying to eliminate was a 10 minute repack followed by another 10
minute repack to push to the server).

-Peff
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Received on Fri Jun 30 07:40:01 2006

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