MySQL Tutorial/Miscellaneous Functions/GET LOCK

GET_LOCK(str,timeout)

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mysql> mysql> SELECT GET_LOCK("lock1",10); +----------------------+ | GET_LOCK("lock1",10) | +----------------------+ | 1 | +----------------------+ 1 row in set (0.00 sec) mysql> SELECT IS_FREE_LOCK("lock2"); +-----------------------+ | IS_FREE_LOCK("lock2") | +-----------------------+ | 1 | +-----------------------+ 1 row in set (0.00 sec) mysql> SELECT GET_LOCK("lock2",10); +----------------------+ | GET_LOCK("lock2",10) | +----------------------+ | 1 | +----------------------+ 1 row in set (0.01 sec) mysql> SELECT RELEASE_LOCK("lock2"); +-----------------------+ | RELEASE_LOCK("lock2") | +-----------------------+ | 1 | +-----------------------+ 1 row in set (0.00 sec) mysql> SELECT RELEASE_LOCK("lock1"); +-----------------------+ | RELEASE_LOCK("lock1") | +-----------------------+ | NULL | +-----------------------+ 1 row in set (0.00 sec) mysql></source>