Foreign keys / Transactions in MySQL.. WTF?

Dagfinn Ilmari Mannsåker ilmari at
Tue Jul 31 19:53:28 BST 2007

Alex Sayle <alexs at> writes:

> To take a snapshot of a MySQL database you need to lock the whole
> database. Once your Database reaches a cretin size and your backups
> take more than your average write interval your clients write will
> be held until the lock is released. The lingering connections also
> mean that your client application halts, and one can easily exhausts
> the available connection count resulting in new connection being
> rejected.
> 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.
> [1]: Yes I'm well aware that this is not how one should use MySQL
>      that wasn't my call and I'm working on a _fix_.

That's what filesystem/block-device level snapshots are for.

"A disappointingly low fraction of the human race is,
 at any given time, on fire." - Stig Sandbeck Mathisen

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