Re: [RFC/PATCH] Add a --nosort option to pack-objects

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 7, 2007, 21:37 UTC
Message-ID: <7vzlwmyyms.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <7v4peu19kr.fsf@gitster.siamese.dyndns.org>

Junio C Hamano <gitster@pobox.com> writes:

Show 7 quoted lines

> Mike Hommey <mh@glandium.org> writes:
>
>> The --nosort option disabled the internal sorting used by pack-objects,
>> and runs the sliding window along the object list litterally as given on
>> stdin.
>
> I think this is a good way to give people an easier way to experiment.

Actually, I take the half of this back.

We need a pair of two good sort orders. The order of objects fed to pack-objects determines the final layout of the resulting pack, and using something like the "recency order" we currently have is to optimize the layout in the resulting pack for typical access patterns.

By using your --nosort, you may be able to influence the deltification process, but the order you use will most likely not match the access pattern of the resulting pack. So it will be an easy, quick-and-dirty way to _experiment_ how the deltification sort order affects the final pack size, but I suspect that the resulting "small" pack won't be useful in the real life.