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Re: does 'svnadmin dump/verify' use the membuffer caches by default?

From: Daniel Shahaf <d.s_at_daniel.shahaf.name>
Date: Fri, 11 Feb 2011 08:47:17 +0200

Stefan Fuhrmann wrote on Thu, Feb 10, 2011 at 00:08:46 +0100:
> On 09.02.2011 03:43, Daniel Shahaf wrote:
> >Stefan,
> >
> >> < wayita> stefan2: danielsh said: does 'svnadmin dump/verify' use the caches by default?
> >><@stefan2> danielsh: yes. However, the biggest performance improvement for dump / verify
> >> will come from delta-caching. This is like 2 merges away. I'm currently
> >> preparing new patch sets for merger
> >Is it possible that 'verify' (and 'dump' when used for verification purposes)
> >would, when using the cache, overlook a corruption that it would have spotted if
> >the cache was disabled?
> In very loose terms, that is "possible" - just like
> any code may malfunction in unforeseen ways.
>

Murphy's law, yes. Any such bugs can go through the normal "find, fix,
backport, patch release" procedure. They weren't my concern.

> But assuming the cache works correctly (storing
> and returning the right data for the right keys),
> it will only prevent *repeated* data reads.
> Assuming further that repeated reads would
> always yield the same results, the cache should
> not affect the results of 'verify' nor 'dump'.
>

Thanks; I accept these assumptions and I agree that under them the
cache shouldn't hide corruptions.

> However, it could hide corruptions that occur
> while the check is running - which is no different
> from today's situation.
>

:-)

> -- Stefan^2.

Thanks,

Daniel
Received on 2011-02-11 07:52:21 CET

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