Code review comment for lp:~spiv/bzr/inventory-delta

John A Meinel wrote:
[...]
> It also picks out the 'optimal' deltas by computing many different ones
> and finding whichever one was the 'smallest'. For local conversions, the
> time to compute 2-3 deltas was much smaller than to apply an inefficient
> delta.

FWIW, the streaming code also does this. My guess (not yet measured) is that
sending less bytes over the network is also a win, especially when one parent
might be a one-liner and the other might be large merge from trunk.

[...]
> There is also:
>
> 3) Being able to resume because you snapshotted periodically as you
> went. This seems even more important for a network transfer.

Yes, although we already don't have this for the network. It would be great to
have...

[...]
> I'm certainly open to the suggestion of getting rid of IDS. I don't like
> having multiple code paths. It just happens that there are *big* wins
> and it is often easier to write optimized code in a different framework.

Sure. Like I said for me it was just getting to be a large hassle to maintain
both paths in my branch, even though they were increasingly sharing a lot of
code for e.g. rich root generation before I deleted IDS.

I'd like to try see if we can cheaply fix the performance issues you report in
other mails without needing IDS. If we do need IDS for a while longer then
fine, although I think we'll want to restrict it to local source, local target,
non-stacked cases only.

Thanks for the measurements and quick feedback.

-Andrew.