Re: [PATCH 0/5] Suggested for PU: revision caching system to significantly speed up packing/walking

> On Fri, 7 Aug 2009, Sam Vilain wrote:
> 
> > Johannes Schindelin wrote:
> > >> the short answer is that cache slices are totally independant of 
> > >> pack files.
> > >>     
> > >
> > > My idea with that was that you already have a SHA-1 map in the pack 
> > > index, and if all you want to be able to accelerate the revision 
> > > walker, you'd probably need something that adds yet another mapping, 
> > > from commit to parents and tree, and from tree to sub-tree and blob 
> > > (so you can avoid unpacking commit and tree objects).
> > >   
> > 
> > Tying indexes together like that is not a good idea in the database 
> > world. Especially as in this case as Nick mentions, the domain is 
> > subtly different (ie pack vs dag). Unfortunately you just can't try to 
> > pretend that they will always be the same; you can't force a full 
> > repack on every ref change!
> 
> Right.  And the rev cache must work even if the repository is not 
> packed.