RE: [Monotone-devel] how to recover damaged database?

[Kelly F. Hickel]

> -----Original Message-----
> From: Nathaniel Smith [mailto:address@hidden
> Sent: Thursday, May 11, 2006 2:13 AM
> To: Kelly F. Hickel
> Cc: address@hidden
> Subject: Re: [Monotone-devel] how to recover damaged database?
> 
> On Sun, May 07, 2006 at 05:11:13PM -0500, Kelly F. Hickel wrote:
> >    While testing the import of our CVS repo, the machine was
> rebooted.  After
> >    the reboot, when I tried to continue importing, I received the
> message
> >    below.  In this instance, I could just start over, but it raises
> the
> >    question of what would happen if we were using this for real?
> We'd have a
> >    daily backup of course, but if this turned out to be
> unrecoverable, that
> >    would be "bad" (I realize that I have no reason to believe it's
> >    unrecoverable, just wondering)....
> 
> Monotone's database is fully ACID[1] transactional.  It takes measures
> that mean in theory, and as far as we know in practice, it is not
> possible to corrupt it through reboots or power failures or any other
> such thing.  It Just Works.  (Put another way, the recovery mechanism
> is always present and always runs quickly and silently when needed.
> If you see any files named like "foo.mtn-journal", leave them be,
> they're the recovery mechanisms record of how to recover :-).)
> 
> Of course, you can still have the disk go bad, or bad memory, or a
> software bug somewhere (even in the OS) that corrupts bytes in flight,
> or... so backups are indeed good, and monotone's design tries to make
> it very hard to actually lose information, whether you get your
> backups right or not...
> 
> Anyway, I suspect the problem is a small bug in the cvs importer, and
> nothing to do with the reboot at all.  If you try doing the import
> into a fresh db, do you still get the same message?

Thanks for the information, it helps.  I had imported one cvs module
which worked fine, then imported another, after that I got the errors.
So, I suspect it would work with a fresh DB.  Since ultimately I want
everything in a single DB, would I just import each module to it's own
DB, then merge the DBs together?

> 
> [1] http://www.wikipedia.com/wiki/ACID , in case you're not a DB
> guy...
> 
> Hope that helps,
> -- Nathaniel
> 
> --
> Sentience can be such a burden.


-- 

Kelly F. Hickel
Senior Software Architect
MQSoftware, Inc
952.345.8677
address@hidden