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From: Thomas Rast <trast@student.ethz.ch>
To: git@vger.kernel.org
Subject: Re: O(#haves*...) behaviour in "have <sha>" processing in upload-pack
Date: Sat, 13 Sep 2008 14:18:43 +0200	[thread overview]
Message-ID: <200809131418.48637.trast@student.ethz.ch> (raw)
In-Reply-To: <200809130211.14091.trast@student.ethz.ch>

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I wrote:
> * Isn't this ok_to_give_up() test moot?  If H is not in our object
>   store, it cannot be of any use in the transfer (of our history to
>   the client).  So if we are going to fake an ACK to stop the client
>   digging on this side of his history, we might as well send it right
>   away.

Never mind this part, it's wrong:

Let B=$(merge-base H W).  Suppose H is unknown to the server, but B is
known.  Then sending a fake ACK as a reply to H will cause

* the client to believe we have everything reachable from H, including
  B, and cease sending any history reachable from H; and thus

* the server to believe that the client does not have B, since it did
  not list this commit in a "have" line.

Sorry for the noise.

- Thomas

-- 
Thomas Rast
trast@student.ethz.ch


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      reply	other threads:[~2008-09-13 12:26 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-09-13  0:11 O(#haves*...) behaviour in "have <sha>" processing in upload-pack Thomas Rast
2008-09-13 12:18 ` Thomas Rast [this message]

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