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Re: fs-rep-sharing branch

From: David Glasser <glasser_at_davidglasser.net>
Date: Tue, 21 Oct 2008 23:29:15 -0700

On Tue, Oct 21, 2008 at 9:39 PM, Listman <listman_at_burble.net> wrote:
>
> On Oct 21, 2008, at 8:05 PM- Oct 21, 2008, Greg Stein wrote:
>
>> After you've changed the editor API, the wc_entry_t structure,
>> migrated all old clients over to svn_checksum_t, and then switched the
>> storage defaults over to sh1, *then* we can talk about "an easy
>> switch".
>>
>> The simple fact is that we're going to be running around with md5
>> checksums in hand for a long while. OR we double-compute, and I'm not
>> willing to burn that much CPU to satisfy somebody's misguided
>> preconception about md5 collisions. And double-compute generally means
>> that we *carry around* both checkums. You wanna update all the APIs
>> for that, too?
>>
>
> +1 (on gregs position for this issue)
>
> lets not introduce more performance overheads based on a corner case.
>
> svn as it stands is way toooo slooow folks... please don't get distracted
> from
> that fact. i'm dealing with 20 minutes commits, 15 minute status checks etc
> and my
> users want to know why...
>
> also, svn already does way too many checksums from what i've been able to
> decipher.

Well, if all you care about is speed, then revert the fsfs rep-sharing
code entirely... it makes FSFS strictly less correct and presumably
strictly slower, bringing only a space benefit which (for FSFS)
appears to not be that large.

--dave

-- 
David Glasser | glasser@davidglasser.net | http://www.davidglasser.net/
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Received on 2008-10-22 08:29:30 CEST

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