Re: git branch performance problem?

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Oct 10, 2007, 21:53 UTC
Message-ID: <Pine.LNX.4.64.0710102251230.4174@racer.site>
In-Reply-To: <f329bf540710101449oad9c9dg85f3821f55fb85ea@mail.gmail.com>

Hi,

On Wed, 10 Oct 2007, Han-Wen Nienhuys wrote:

Show 19 quoted lines

> 2007/10/10, Lars Hjemli <hjemli@gmail.com>:
> > On 10/10/07, J. Bruce Fields <bfields@fieldses.org> wrote:
> > > On Wed, Oct 10, 2007 at 06:30:02PM -0300, Han-Wen Nienhuys wrote:
> > > > could it be that GC does not handle cyclic alternates correctly?
> > >
> > > Does it handle alternates at all?  If you run git-gc on a repository 
> > > which other repositories get objects from, then my impression was 
> > > that bad things happen.
> > >
> >
> > AFAIK 'git gc' is safe, while 'git gc --prune' will remove loose
> > (unreferenced) objects.
> 
> Yes, I think that in this case, gc --prune was run accidentally, but
> given that the history of the program invoking git just died, I'm not
> sure how to figure that out.
> 
> Maybe gc --prune could follow the alternates and abort if a cycle was 
> detected?

I think we talked about this quite some time ago, and the resolution was that it is too hard.

Now that it bit somebody in real life, I think we have to try harder.

And probably the best place to check would be git-prune, not git-gc, since that is the program (called by gc) that most probably killed your repo.

Come to think of it, it should probably be part of git-repack, too.

Will try to cobble up a patch, Dscho