Re: thin packs ending up fat

From: Junio C Hamano <gitster@pobox.com>
Date: Jan 13, 2012, 07:19 UTC
Message-ID: <7vmx9sysqe.fsf@alter.siamese.dyndns.org>
In-Reply-To: <20120113015117.GA8245@sigill.intra.peff.net>

Jeff King <peff@peff.net> writes:

Show 7 quoted lines

> On Thu, Jan 12, 2012 at 05:31:42PM -0800, Junio C Hamano wrote:
>
>> From: Jeff King <peff@peff.net>
>> Subject: [PATCH] thin-pack: try harder to create delta against preferred base
>
> I just sat down to write a nicer commit message, and behold, it was done
> for me. Thanks.

Thank _you_ for a quick response and correction.

I wanted to make sure I understood the root cause of the issue and the approach the patch takes to address it, instead of committing something that smelled correct. And the only way I know to do so is to write it down.

Especiallly, before coming up with the description, I was wondering if this kind of symptom appears in non-thin cases, but after writing down the justification for this patch, it became clear that we wouldn't have to worry too much about that case. In a non-thin pack, we need to record one object at least in a delta family in inflated base form, so we may as well send that one near the tip that is already in that form for that, letting the existing "avoid futile delta" heuristics to kick in. Other objects in the same delta family will delta against it.