Re: [PATCH 0/4] Honor core.deltaBaseCacheLimit during index-pack

> Johannes Schindelin wrote:
> 
> > On Mon, 14 Jul 2008, Andreas Ericsson wrote:
> > 
> > > Sorry for being clueless here, but why does the older versions need
> > > to be kept in-memory anyway? Aren't we applying the delta each time
> > > we find one, repeatedly creating a new base-object in-memory for
> > > each delta? If we aren't doing that, why do we need more than just
> > > a small amount of memory just for keeping the delta?
> > 
> > Think of a delta chain of 49 delta objects, 1 base object.  Now reconstruct
> > all of the objects.
> > 
> > If you do it one by one, not storing the intermediate results, you end up
> > applying 1 delta for the first, 2 for the second (first the first, then the
> > second), and so on, in total 1 + 2 + 3 + ... + 49 = 49 * 50 / 2 = 1225
> > times.
> > 
> > Compare that to the 49 times when reusing the intermediate results.
> > 
> 
> [...]
>
> while (pop_delta(patch_stack))
> 	apply_delta(base_object, delta);
> 
> where "apply_delta" replaces the base_object->blob with the delta 
> applied, releasing the previously used memory?