Foreign keys / Transactions in MySQL.. WTF?

Jonathan T. Rockway jon at
Wed Aug 1 06:40:24 BST 2007

On Tue, Jul 31, 2007 at 07:53:28PM +0100, Dagfinn Ilmari Mannsåker wrote:
> Alex Sayle <alexs at> writes:
> > Now $work's DB currently takes 90 mins to dump out, and our average
> > mean time between write is 6 seconds[1]. you do the maths.
> That's what filesystem/block-device level snapshots are for.

Does MySQL guarantee that the filesystem is in a legal state at all
times?  If not, a filesystem-level backup is just going to give you

Berkeley DB supports hot backups (if you copy the files in a certain
order), and MySQL can use BDB as a backend... but I don't know if you
can hot-copy MySQL's BDBs, and I don't know what InnoDB (etc.)
features you lose.

Hell, I don't even know if MySQL can use BDB anymore... but I do know
that you could lose data if you just blindly copy filesystem blocks.

Jonathan Rockway

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