Re: [RFC PATCH] Reduce the number of connects when fetching

[Daniel Barkalow <barkalow@iabervon.org>]

On Mon, 5 Nov 2007, Junio C Hamano wrote:

> Daniel Barkalow <barkalow@iabervon.org> writes:
> 
> > The idea is to keep the open connection in the data for the transport in 
> > between getting the list of refs and doing anything further. This 
> > therefore moves the connection-handling aspects outside of fetch-pack() 
> > and handles them primarily in transport.c.
> 
> The idea is very sound.  The scripted version of git-fetch used
> a separate ls-remote only because peek-remote and fetch-pack
> were separate programs.

I figured that had to be the case, due to the way the protocol acts at the 
beginning.

> > ... In particular, I don't know if there's a way to have the 
> > connection end up in a state where objects for more refs can be requested 
> > after some refs have been requested and the resulting objects read.
> 
> The upload-pack protocol goes "S: here are what I have, C: I
> want these, C: I have these, S: ok, continue, C: I have these,
> S: ok, continue, C: I have these, S: ok, I've heard enough, C:
> done, S: packfile is here", so after packfile generation starts
> there is nothing further the downloader can say.
> 
> Otherwise you would be able to do the tag following using the
> same connection, but that is unfortunately not a case.

It would be nice if this could continue: "C: I also want these, S: ok, 
heard enough, C: done, S: another packfile is here"; we should be able to 
identify the end of the packfile on both ends to resume doing other 
things.

Or, maybe, "C: I also want these single objects, S: here's a thin pack of 
them", since it's exclusively tags pointing to objects we have just 
gotten.

	-Daniel
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