[kwlug-disc] how to recover corrupt mysql database from .frm files?

Khalid Baheyeldin kb at 2bits.com
Wed Feb 24 09:35:35 EST 2010


On Wed, Feb 24, 2010 at 7:11 AM, Robert P. J. Day <rpjday at crashcourse.ca>wrote:

> On Wed, 24 Feb 2010, Robert P. J. Day wrote:
>
> >   a colleague asks me if there's a way to recover a mysql database
> > that was being hosted by someone else and was apparently corrupted
> > in ways that are not at all obvious.
> >
> >   all the hosting company is providing him with is a tar file of the
> > /var/lib/mysql/<db> directory, which consists of nothing but .frm
> > files (so it's in innodb format, correct?).  they won't give him the
> > ibdata1 file or ib log files, for security reasons.
>
> ... snip ...
>
>  one of my first thoughts was whether there's a utility that will
> extract from the ibdata1 file and/or the log files *only* the
> information that's relevant to this one database.  i suspect the
> admins at the hosting company could be persuaded to provide *that*,
> once they're convinced that that doesn't represent a security issue.
>
>
One more thing about ibdata, they can't be moved from one machine to
another and expected to work as is. For MyISAM, it is possible to move
.MYI and .MYD and have them work. But for InnoDB, it is not that simple.

Did they try to run mysqldump on his database only?

InnoDB attempts to recover from corruption automatically when it starts up.
Does the logs show anything? If there is corruption, is it for his database
only
or for everyone on that machine? I find it hard that only one database is
affected.

MaatKit may give some clues here, but if his host is not releasing the bdata
files (perhaps with good reason), there is little he can do about it.
-- 
Khalid M. Baheyeldin
2bits.com, Inc.
http://2bits.com
Drupal optimization, development, customization and consulting.
Simplicity is prerequisite for reliability. --  Edsger W.Dijkstra
Simplicity is the ultimate sophistication. --   Leonardo da Vinci
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