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User Defined Locks
===================
A user can create a "lock" which is scoped to their user space. Multiple
session of the user can see the lock.
.. code-block:: mysql
SELECT GET_LOCK();
SELECT GET_LOCKS();
SELECT RELEASE_LOCK();
SELECT RELEASE_LOCK();
SELECT RELEASE_LOCKS();
SELECT is_free_lock();
SELECT is_used_lock();
If a session should exit, whatever locks it was holding will be released.
.. todo::
are locks recursive?
Please note, get_lock() was designed to be compatible with MySQL. If you
hold any locks when calling get_lock() they will be released. For this
reason you may want to consider calling get_locks() instead.
Information on all barriers can be found in the DATA_DICTIONARY.USER_LOCKS
table;
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