Re: thin packs ending up fat

On Thu, Jan 12, 2012 at 05:31:42PM -0800, Junio C Hamano wrote:

From: Jeff King <redacted>
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.

When creating a thin-pack to transfer recent history, it is likely that we
will try to send an object that is recorded in full, as it is newer.  But
the heuristics to avoid recomputing futile delta effectively forbids us
from attempting to express such an object as a delta based on another
object. Sending an object in full is often more expensive than sending a
suboptimal delta based on other objects, and it is even more so if we
could use an object we know the receiving end already has (i.e. referred
base object) as the delta base.

s/referred/preferred/

Tweak the recomputation avoidance logic, so that we do not punt on
computing delta against a preferred base object.

Signed-off-by: Junio C Hamano <redacted>

Other than that, it looks good to me.

Signed-off-by: Jeff King <redacted>

I'll try to deploy this to GitHub in the near future. I doubt we'll see
much of a dent in our bandwidth, though, as small fetches that this
helps are probably lost in the noise of clones.

-Peff