Performance Schema user_variables_by_thread Table

This table exposes user-defined variables set within active threads, allowing inspection of custom variables across all sessions.

The user_variables_by_thread table is available from MariaDB 10.5.2.

The user_variables_by_thread table contains information about user-defined variables and the threads that defined them.

TRUNCATE TABLE cannot be performed on the table.

The table contains the following columns:

Column	Description
THREAD_ID	The thread identifier of the session in which the variable is defined.
VARIABLE_NAME	The variable name, without the leading @ character.
VARIABLE_VALUE	The variable value

Example

SET @var = 0;

SELECT * FROM user_variables_by_thread;
+-----------+---------------+----------------+
| THREAD_ID | VARIABLE_NAME | VARIABLE_VALUE |
+-----------+---------------+----------------+
|        11 | var           | 0              |
+-----------+---------------+----------------+

See Also

• User-defined variables

• Information Schema USER_VARIABLES Table

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