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Re: fs-rep-sharing branch

From: Ivan Zhakov <ivan_at_visualsvn.com>
Date: Wed, 22 Oct 2008 11:42:04 +0400

On Wed, Oct 22, 2008 at 10:29 AM, David Glasser
<glasser_at_davidglasser.net> wrote:
> 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.
>
I agree with David: Subversion reliability is much more important than
speed. Also I do not understand why we so care about disk space for
repository: disk space is very cheap and become cheaper every day.
Think that priority list should be:
- Reliability
- Speed (CPU/memory usage)
- Disk space

-- 
Ivan Zhakov
VisualSVN Team
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Received on 2008-10-22 09:42:19 CEST

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