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From: bdowning@lavos•net (Brian Downing)
To: Junio C Hamano <gitster@pobox•com>
Cc: git@vger•kernel.org
Subject: Re: Preferring shallower deltas on repack
Date: Mon, 9 Jul 2007 02:36:12 -0500	[thread overview]
Message-ID: <20070709073612.GK4087@lavos.net> (raw)
In-Reply-To: <7vbqemvxyb.fsf@assigned-by-dhcp.cox.net>

On Mon, Jul 09, 2007 at 12:27:24AM -0700, Junio C Hamano wrote:
> >> It would become worrysome (*BUT* infinitely more interesting)
> >> once you start talking about a tradeoff between slightly larger
> >> delta and much shorter delta.  Such a tradeoff, if done right,
> >> would make a lot of sense, but I do not offhand think of a way
> >> to strike a proper balance between them efficiently.
> >
> > Yeah, I was thinking about that too, and came to the same conclusion.
> > I suspect you'd have to save a /lot/ of delta depth to want to pay any
> > more I/O, though.
> 
> That may not be so.  Deeper delta also means more I/O (and
> worse, because they can be from discontiguous areas) plus delta
> application.

Good point.

I guess if I were to think about a metric for deciding whether to go for
a small deep delta or a larger shallow one, I would probably keep track
of the total path size (the sum of the base size and all the delta sizes)
for each entry, and play with a weighting formula of single delta size
verses total path size.

-bcd

  reply	other threads:[~2007-07-09  7:36 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-07-09  4:43 Preferring shallower deltas on repack Brian Downing
2007-07-09  4:45 ` [PATCH] pack-objects: Prefer shallower deltas if the size is equal Brian Downing
2007-07-09  5:31 ` Preferring shallower deltas on repack Junio C Hamano
2007-07-09  5:43   ` Junio C Hamano
2007-07-09  6:52   ` Brian Downing
2007-07-09  7:27     ` Junio C Hamano
2007-07-09  7:36       ` Brian Downing [this message]
2007-07-09 15:58   ` Nicolas Pitre
2007-07-09 16:39     ` Junio C Hamano
2007-07-09 18:53       ` Brian Downing
2007-07-09 19:13         ` Nicolas Pitre
2007-07-09 19:24           ` Brian Downing
2007-07-09 19:49             ` Brian Downing
2007-07-09 20:22               ` Nicolas Pitre
2007-07-09 20:23               ` Brian Downing
2007-07-09 19:30         ` [PATCH] Shoddy pack information tool Brian Downing
2007-07-11 21:55           ` Junio C Hamano
2007-07-12  3:02             ` [PATCH] Pack " Brian Downing
2007-07-09  5:41 ` Preferring shallower deltas on repack Linus Torvalds

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