IS_USED_LOCK()
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The parent of this page is: Functions for MariaDB Xpand
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Overview
Returns the connection identifier of the client session that holds a named user-level lock.
USAGE
IS_USED_LOCK(name)
Argument Name | Description |
|---|---|
| The string argument that is to be checked |
DETAILS
IS_USED_LOCK() is a locking function that returns the connection identifier of a named user-level lock if it is locked.
The return value is NULL if the name argument is not a locked user-level lock, otherwise it is a connection identifier.
An error is returned if the name argument is NULL.
EXAMPLES
SELECT IS_USED_LOCK('mylock');
+------------------------+
| IS_USED_LOCK('mylock') |
+------------------------+
| NULL |
+------------------------+
SELECT IS_USED_LOCK(NULL);
ERROR 1 (HY000): [24576] Unknown prepared param type: "t_null"
SELECT IS_USED_LOCK(1);
+-----------------+
| IS_USED_LOCK(1) |
+-----------------+
| NULL |
+-----------------+