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Re: fs-rep-sharing branch

From: Greg Stein <gstein_at_gmail.com>
Date: Wed, 22 Oct 2008 12:37:44 -0700

On Wed, Oct 22, 2008 at 9:32 AM, David Glasser <glasser_at_davidglasser.net> wrote:
> On Wed, Oct 22, 2008 at 5:34 AM, Greg Stein <gstein_at_gmail.com> wrote:
>...
>> Later, the idea of researchers surfaced, and that they'd be trying to
>> store file pairs with the same hash. I grant your scenario is valid.
>...
> It's still a regression vs 1.5. Can you at least acknowledge that?

I did; see above :-)

That said, I disagree that it is a common enough use case to go for a
double-compute which burns 99.9% of our users. IOW, I'm more than
willing to tell 0.01% of our users to spend a bit of extra work, in
order to use Subversion.

From day one, we said, "let's solve the 80-90 percent problem WELL,
and make the rest doable." Well... those researchers have
alternatives: store the matched pair in a .tar file. Or gzip it. Or
hell... rot13 to the rescue!!

> Also, if double-hash-computation is such a horrible thing, then why is
> it OK for fs_base to use it but not fs_fs?

Never said it was okay. I raised the issue when that commit arrived,
and (iirc) the feedback was "that is just temporary code". My own
experience, and Ivan also confirmed: the server can often be
CPU-bound, so an extra hash computation is a Bad Thing(tm), and we
shouldn't do it.

Cheers,
-g

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Received on 2008-10-22 21:37:57 CEST

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