Avoid locking tables during mysql dump

[Toub]

Piwik default table engine is InnoDB since Piwik 2.1.

In that case, mysqldump documentation recommends to use --single-transaction option instead of --lock-tables.

This avoids LOCKS conflicts with piwik application and has much better performances.

As --lock-tables is enabled by default (due to --opt shortcut option), you have to explicitly disable it:

mysqldump --skip-lock-tables --single-transaction ...

[pierreozoux]

Nice catch :)
Do you want to PR? :P

(You must have a big setup to spot this? Or just reading the doc?)

[Toub]

I experienced this issue with an other application, and the performance impact is real when accessing to the database in write mode during the backup.

I don't know how it affects piwik, nor how piwik manages the DB pool, but it is a no-cost optimization, so enjoy! ;-)

[Toub]

Thanks @stefancrain