Re: git-gc "--aggressive" somewhat broken

On Fri, 6 Jul 2007, Linus Torvalds wrote:

On Fri, 6 Jul 2007, Linus Torvalds wrote:

quoted

If we want to be really aggressive, we migth decide to pass a new flag to 
pack-objects that does something closer to what "aggressive" was meant to 
do: it would use existing delta's if they exist, but _despite_ existing it 
could look if there are even better choices.

This is a totally untested patch that may or may not work.

The reason I say "may not work" is not just that I haven't really tested 
it, it's also because I haven't thought it through very well.

In particular, does this possibly cause infinite loops of delta chains? 
Probably. It would need code to explicitly make sure that we don't do 
that, but I couldn't even convince myself as to why we might not hit that 
case _already_ with delta re-use, so maybe there's something going that 
protects us against it.

There is.

Anyway, consider this a starting point for somebody else who wants to 
really try to look into this.

This is a real teaser.  But I have real work to do if I want to leave on 
vacation this summer, and therefore I'll then be on vacation.  So if I 
end up looking at it myself it will be in September.


Nicolas