Is it safe to delete mergeinfo.db?

[Eric Hanchrow <of...@blarg.net>]

(I apologize if I've this is the second time I've asked this -- I
could have sworn I already did, but can find no trace of it)

I am running a version of the svn trunk compiled Aug 10 2007,
13:57:42, and have noticed some odd behavior when trying out the new
automatic merge-tracking feature:

    svn log -g file://$HOME/svn-repos/trunk/doodles/plt-scheme > /tmp/yow
    ../live/subversion/libsvn_fs_fs/tree.c:2709: (apr_err=160013)
    svn: File not found: revision 4525, path '/trunk/doodles/plt-scheme/irc-v2/bot.ss'

I assume that a combination of my not knowing what I'm doing, and a
bug in my old version of Subversion, has somehow screwed up
mergeinfo.db, and I don't particularly care about its contents anyway.

I'd like to upgrade my version of subversion and keep using my repo.
But I worry that my mergeinfo.db is in some bad state that is the
fault of old code (either the Aug 10 version that I'm currently
running, or one that's even older, which created it), and that if I
upgrade to a newer trunk version of svn, and still have the same
trouble, no developer will want to investigate, since the problem is
indeed likely to have been caused by old code.  That's why I want to
delete it.

So ... can I safely nuke mergeinfo.db?  For what it's worth, I made a
hotcopy of my repo, deleted the mergeinfo.db from that hotcopy, and
ran "svn log -g" on it; it completed with no errors.

-- 
Documentation exists, but never seems to be complete.
        -- Dennis Ritchie, 1972

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Re: Is it safe to delete mergeinfo.db?

[Daniel Rall <dl...@collab.net>]

On Wed, 19 Sep 2007, Mark Phippard wrote:

> On 9/19/07, Malcolm Rowe <ma...@farside.org.uk> wrote:
...
> > Will it be recreated _empty_, or will it be repopulated with the
> > existing mergeinfo data?  (I assume we need the latter behaviour
> > somewhere anyway (though perhaps we're planning to make it explicit),
> > since we'll nee some way of migrating pre-1.5-era-svnmerge.py
> > properties?)
> 
> It seems like someone needs to show real problems and corruption in
> the database before we ought to go that far.  I do not think it has
> anyway to populate itself from the repository contents.  It just
> creates empty as a by product of making it easy for existing
> repositories to be used with 1.5.

A missing mergeinfo.db will currently be re-created empty.

> I cannot see svnmerge.py script doing anything other than converting
> the property format and letting the normal property handling routines
> populate the database.
> 
> If someone needs to recreate the info, shouldn't they dump/load?

We have two separate issues dealing with migration of pre-existing
repositories, one for dealing specifically with svnmerge.py, and
another for turning copyfrom info into mergeinfo:

2875 FEATURE P3 svnadmin load should add mergeinfo for copies
2878 FEATURE P3 svnmerge.py migration script

Re: Is it safe to delete mergeinfo.db?

[Daniel Rall <dl...@collab.net>]

On Wed, 19 Sep 2007, Malcolm Rowe wrote:

> On Wed, Sep 19, 2007 at 03:28:48PM -0400, Mark Phippard wrote:
...
> > It seems like someone needs to show real problems and corruption in
> > the database before we ought to go that far.  I do not think it has
> 
> I agree, and this is something that we can do post-1.5.  I'm just a
> little worried about using an index that we can't recreate online,
> that's all.
...

For now, the answer is "perform backups".  That said, do we need to
tweak tools/backup/hot-backup.py or any other scripts to handle
mergeinfo.db?

Re: Is it safe to delete mergeinfo.db?

[Malcolm Rowe <ma...@farside.org.uk>]

On Wed, Sep 19, 2007 at 03:28:48PM -0400, Mark Phippard wrote:
> anyway to populate itself from the repository contents.  It just
> creates empty as a by product of making it easy for existing
> repositories to be used with 1.5.
> 

So the answer for anyone in Eric's position would be "You can delete it
as long as you're not depending upon it for anything; dump/load to make
sure", I guess.

> It seems like someone needs to show real problems and corruption in
> the database before we ought to go that far.  I do not think it has

I agree, and this is something that we can do post-1.5.  I'm just a
little worried about using an index that we can't recreate online,
that's all.

(Tangentally, the new 'svn mergeinfo' command -- which I assume runs off
the index -- makes things slightly better, since at least we're now able
to easily diagnose a property/index mismatch).

> If someone needs to recreate the info, shouldn't they dump/load?
> 

There's no reason they should need to take the repository offline to
update an index, no.

Regards,
Malcolm

Re: Is it safe to delete mergeinfo.db?

[Mark Phippard <ma...@gmail.com>]

On 9/19/07, Malcolm Rowe <ma...@farside.org.uk> wrote:
> On Wed, Sep 19, 2007 at 02:53:54PM -0400, Mark Phippard wrote:
> > > So ... can I safely nuke mergeinfo.db?  For what it's worth, I made a
> > > hotcopy of my repo, deleted the mergeinfo.db from that hotcopy, and
> > > ran "svn log -g" on it; it completed with no errors.
> >
> > Yes you did already send.  Dan Rall indicated you can just delete the
> > .db file and it will be created again the next time something needs to
> > write to it.
> >
>
> Will it be recreated _empty_, or will it be repopulated with the
> existing mergeinfo data?  (I assume we need the latter behaviour
> somewhere anyway (though perhaps we're planning to make it explicit),
> since we'll nee some way of migrating pre-1.5-era-svnmerge.py
> properties?)

It seems like someone needs to show real problems and corruption in
the database before we ought to go that far.  I do not think it has
anyway to populate itself from the repository contents.  It just
creates empty as a by product of making it easy for existing
repositories to be used with 1.5.

I cannot see svnmerge.py script doing anything other than converting
the property format and letting the normal property handling routines
populate the database.

If someone needs to recreate the info, shouldn't they dump/load?

-- 
Thanks

Mark Phippard
http://markphip.blogspot.com/

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Re: Is it safe to delete mergeinfo.db?

[Malcolm Rowe <ma...@farside.org.uk>]

On Wed, Sep 19, 2007 at 02:53:54PM -0400, Mark Phippard wrote:
> > So ... can I safely nuke mergeinfo.db?  For what it's worth, I made a
> > hotcopy of my repo, deleted the mergeinfo.db from that hotcopy, and
> > ran "svn log -g" on it; it completed with no errors.
> 
> Yes you did already send.  Dan Rall indicated you can just delete the
> .db file and it will be created again the next time something needs to
> write to it.
> 

Will it be recreated _empty_, or will it be repopulated with the
existing mergeinfo data?  (I assume we need the latter behaviour
somewhere anyway (though perhaps we're planning to make it explicit),
since we'll nee some way of migrating pre-1.5-era-svnmerge.py
properties?)

Regards,
Malcolm

Re: Is it safe to delete mergeinfo.db?

[Mark Phippard <ma...@gmail.com>]

On 9/19/07, Eric Hanchrow <of...@blarg.net> wrote:
> (I apologize if I've this is the second time I've asked this -- I
> could have sworn I already did, but can find no trace of it)
>
> I am running a version of the svn trunk compiled Aug 10 2007,
> 13:57:42, and have noticed some odd behavior when trying out the new
> automatic merge-tracking feature:
>
>     svn log -g file://$HOME/svn-repos/trunk/doodles/plt-scheme > /tmp/yow
>     ../live/subversion/libsvn_fs_fs/tree.c:2709: (apr_err=160013)
>     svn: File not found: revision 4525, path '/trunk/doodles/plt-scheme/irc-v2/bot.ss'
>
> I assume that a combination of my not knowing what I'm doing, and a
> bug in my old version of Subversion, has somehow screwed up
> mergeinfo.db, and I don't particularly care about its contents anyway.
>
> I'd like to upgrade my version of subversion and keep using my repo.
> But I worry that my mergeinfo.db is in some bad state that is the
> fault of old code (either the Aug 10 version that I'm currently
> running, or one that's even older, which created it), and that if I
> upgrade to a newer trunk version of svn, and still have the same
> trouble, no developer will want to investigate, since the problem is
> indeed likely to have been caused by old code.  That's why I want to
> delete it.
>
> So ... can I safely nuke mergeinfo.db?  For what it's worth, I made a
> hotcopy of my repo, deleted the mergeinfo.db from that hotcopy, and
> ran "svn log -g" on it; it completed with no errors.

Yes you did already send.  Dan Rall indicated you can just delete the
.db file and it will be created again the next time something needs to
write to it.

-- 
Thanks

Mark Phippard
http://markphip.blogspot.com/

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Re: Is it safe to delete mergeinfo.db?

[Daniel Rall <dl...@collab.net>]

On Wed, 19 Sep 2007, Eric Hanchrow wrote:

> (I apologize if I've this is the second time I've asked this -- I
> could have sworn I already did, but can find no trace of it)

You asked on IRC.

...
> So ... can I safely nuke mergeinfo.db?
...

Yes.  :-)