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From: "Shawn O. Pearce" <spearce@spearce.org>
To: "Randal L. Schwartz" <merlyn@stonehenge.com>
Cc: James Cloos <cloos@jhcloos.com>,
	git@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Eriksen <s022018@student.dtu.dk>
Subject: Re: Distribution of longest common hash prefixes
Date: Tue, 3 Apr 2007 13:21:23 -0400	[thread overview]
Message-ID: <20070403172123.GD27706@spearce.org> (raw)
In-Reply-To: <867istcrhr.fsf@blue.stonehenge.com>

"Randal L. Schwartz" <merlyn@stonehenge.com> wrote:
> >>>>> "James" == James Cloos <cloos@jhcloos.com> writes:
> 
> James> With that version the kernel gives:
> 
> James> 0: 
> James> 1: 
> James> 2: 
> James> 3: 565
> James> 4: 288450
> James> 5: 139080
> James> 6: 10699
> James> 7: 700
> James> 8: 32
> James> 9: 2
> 
> Fascinating.  So you can spell out *any* commit in linux-2.6.git with
> 10 hex chars.  What do we need 40 for, again? :)

Well, the other thing is those 2 commits at 9 bytes probably were
not that way a year ago.  One of those might have only needed 8,
and the other is newer, so now you need 9.

What the above tells me is that 8 is almost a safe default for our
abbreviations, but isn't safe enough, as there are collisions past 8.

-- 
Shawn.

  reply	other threads:[~2007-04-03 17:21 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-02 14:58 Distribution of longest common hash prefixes Peter Eriksen
2007-04-02 15:20 ` Linus Torvalds
2007-04-02 16:29   ` Randal L. Schwartz
2007-04-02 17:00     ` Linus Torvalds
2007-04-02 17:17       ` Randal L. Schwartz
2007-04-02 17:33         ` Randal L. Schwartz
2007-04-03 17:04           ` James Cloos
2007-04-03 17:11             ` Randal L. Schwartz
2007-04-03 17:21               ` Shawn O. Pearce [this message]
2007-04-03 17:50                 ` Linus Torvalds
2007-04-03 18:22                   ` Junio C Hamano
2007-04-03 19:27                     ` Linus Torvalds
2007-04-03 19:34                     ` Nicolas Pitre
2007-04-03 20:25                       ` Junio C Hamano
2007-04-03 20:39                         ` Nicolas Pitre
2007-04-03 23:08                           ` Olivier Galibert
2007-04-03 23:22                             ` Linus Torvalds
2007-04-04 21:03                   ` James Cloos
2007-04-02 17:18     ` James Cloos
2007-04-02 15:28 ` Peter Eriksen

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