Re: [ANNOUNCE] more archives of this list

From: Jeff King <peff@peff.net>
Date: Aug 5, 2016, 20:20 UTC
Message-ID: <20160805202046.pd42xl76c2sbf272@sigill.intra.peff.net>
In-Reply-To: <CACsJy8DkNUD_dKwnx9nZsgvSxgdA8MH=2+rEWzMFdkigmhpJ5g@mail.gmail.com>

On Fri, Aug 05, 2016 at 05:04:27PM +0200, Duy Nguyen wrote:

Show 11 quoted lines

> On Fri, Aug 5, 2016 at 11:28 AM, Jeff King <peff@peff.net> wrote:
> > There was discussion a long time ago about storing a common zlib
> > dictionary in the packfile and using it for all of the objects. I don't
> > recall whether there were any patches, though. It does create some
> > complications with serving clones/fetches, as they may ask for a subset
> > of the objects (so you have to send them the whole dictionary, which may
> > be a lot of overhead if you're only fetching a few objects).
> 
> I'm nit picking since it's not actually "all objects". But pack v4
> patches have two dictionaries (or more? i don't remember) for commits
> and trees :)

I couldn't remember if that zlib stuff was part of packv4 or not. I like many of the ideas in pack v4, but I do worry a lot about the compatibility issues, as packv2 is the on-the-wire format.

Being able to send bytes directly off disk with minimal processing is a key thing that makes running a large git hosting site practical. One of the things that makes nervous is having to do on-the-fly conversion when serving fetches and clones (but to be clear that is just gut nervousness; I haven't done any actual testing with the proto-packv4 patches).

-Peff