I think this is just handled by the setting of the variable 'lock_wait_timeout' :

http://dev.mysql.com/doc/refman/5.6/en/server-system-variables.html#sysvar_lock_wait_timeout

But also you should know 'innodb_lock_wait_timeout'

http://dev.mysql.com/doc/refman/5.6/en/innodb-parameters.html#sysvar_innodb_lock_wait_timeout

It is true that some backup tools will LOCK (complete) tables. This applies to some backup tools deployed on various hosting systems and integrated into various 'Control Panel' applications But IMO this just reflects that the still think MySQL is == MyISAM (because wiht MyISAM etc. there is no other way to ensure consistency). With InnoDB you may 'backup in a single transaction'. mysqldump (http://dev.mysql.com/doc/refman/5.1/en/mysqldump.html#option_mysqldump_single-transaction) and also other tools support this (at least SQLyog/SJA does).

On Wed, May 28, 2014 at 3:43 PM, Jimmy Thrasibule <thrasibule.jimmy@gmail.com> wrote:

Hello,

Some backup tools make use of table locking to ensure data consistency
during the operation. I'm wondering about what happens to the incoming
queries for the table being locked.

Obviously, the request will be pending until the table is unlocked but
this way some timeout value may be reached. Another option could be to
accept and queue all requests and replay them once the table is
unlocked.

So can you tell me how MariaDB is handling such situation. Is the
second option (asynchronous request), can be activated within MariaDB?

Best,
Jimmy

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