Re: [RFC][RESEND][PATCH] Allow fetching from multiple repositories at once

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Sep 23, 2006, 17:54 UTC
Message-ID: <Pine.LNX.4.63.0609231947340.25853@wbgn013.biozentrum.uni-wuerzburg.de>
In-Reply-To: <20060923173943.GA20017@pasky.or.cz>

Hi,

On Sat, 23 Sep 2006, Petr Baudis wrote:

Show 37 quoted lines

> Dear diary, on Sat, Sep 23, 2006 at 07:23:01PM CEST, I got a letter
> where Johannes Schindelin <Johannes.Schindelin@gmx.de> said that...
> > On Sat, 23 Sep 2006, Petr Baudis wrote:
> > 
> > > Dear diary, on Sat, Sep 23, 2006 at 06:57:36PM CEST, I got a letter
> > > where A Large Angry SCM <gitzilla@gmail.com> said that...
> > > > Petr Baudis wrote:
> > > > >You still need to pass git-fetch-pack some URL in addition to the
> > > > >repositories - it is used only for git_connect(), the purpose is that
> > > > >repositories must be local directories so if you want to talk remote, you
> > > > >need to do something like
> > > > >
> > > > >	git-fetch-pack git://kernel.org/pub/scm/git/git.git 
> > > > >	--repo=/pub/scm/git/git.git master next 
> > > > >	--repo=/pub/scm/cogito/cogito.git master
> > > > >
> > > > 
> > > > Can't this be done with a simple wrapper around git-fetch* ?
> > > 
> > > The point is that that is too slow (the difference is noticeable
> > > especiall in the case there is no new stuff ready), you need to create a
> > > connection and do whole lot of work for each of the repositories.
> > 
> > I still firmly believe that it would be way more efficient to fetch all 
> > those branches into _one_ proxy repository. Especially since you can reuse 
> > the objects with an alternate, which has an additional benefit over your 
> > approach.
> 
>   Huh? You can reuse the objects with my approach as well. Actually, it
> is automagically done so.
> 
>   With proxy repository, you would still need a server-side setup to
> maintain that repository, and specialized client-side porcelain to fetch
> from it. My approach initially requires some core changes (which aren't
> very pretty as it is but are not very fundamental or logically intrusive
> either) but in the longer run it pays off since you don't need a
> convoluted server-side setup for that.

No, you do not need _any_ server-side setup. And you do not need any specialized client-side porcelain other than a script, which just does the job.

The point is, your changes are not only intrusive, they are unnecessary.

You can even declare the first repository as the proxy. Sketch of script:

	- find which branches are wanted at all,

	- do the fetch (of all wanted branches) in the first repository,
	  storing the refs under refs/multi/,

	- for each repository

		- ensure that the first repo is given as alternative

		- store the branches this repo wants (you only need to 
		  update the refs, since you have all the objects)

This is not particularly complicated, is it?

Ciao, Dscho