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Re: revprop packing: why aren't _all_ revprops packed?

From: Daniel Shahaf <danielsh_at_elego.de>
Date: Fri, 1 Jul 2011 16:22:15 +0300

Mark Phippard wrote on Fri, Jul 01, 2011 at 09:10:31 -0400:
> On Thu, Jun 30, 2011 at 5:21 PM, Peter Samuelson <peter_at_p12n.org> wrote:
> >
> > [kmradke_at_rockwellcollins.com]
> >> I would love to have revprop packing, but not at the cost of
> >> potentially disabling the use of traditional backup software.
> >>
> >> Is there a way to disable fsfs revprop packing, or at least have
> >> it function in an atomic way like the regular rev packing?
> >
> > Hijacking the thread to veer _slightly_ off topic:
> >
> > Why is revprop packing an explicit 'svnadmin pack' operation?  If we
> > agree to put revprops in sqlite, why not do that from the start?  Just
> > open the shard-specific sqlite file, creating it if necessary, and
> > write the new set of revprops there.  No distinction between packed and
> > unpacked revprops, no 'min-unpacked-revprop' file.
> >
> > Was there a good reason not to do it that way?
>
> Wouldn't the concerns that Kevin has raised kick in if we did this?
> Basically you could not do a safe backup of a repository because if a
> commit happens during the backup we will be writing to the SQLite
> database.
>

They would.

For the record, some ways to solve that concern are --

1. hotcopy
2. take an atomic diks snapshot
3. teach FSFS to pack revision shards without packing revprop shards
4. backup just revprops.db in the SQLite-safe way
   (grab an SQLite-level lock, cp(1), release lock)

> --
> Thanks
>
> Mark Phippard
> http://markphip.blogspot.com/
Received on 2011-07-01 15:23:16 CEST

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