> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/system-tables/performance-schema/performance-schema-tables/performance-schema-user_variables_by_thread-table.md).

# Performance Schema user\_variables\_by\_thread Table

{% hint style="info" %}
The `user_variables_by_thread` table is available from MariaDB 10.5.2.
{% endhint %}

The `user_variables_by_thread` table contains information about [user-defined variables](/docs/server/reference/sql-structure/sql-language-structure/user-defined-variables.md) and the threads that defined them.

[TRUNCATE TABLE](/docs/server/reference/sql-statements/table-statements/truncate-table.md) 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

```sql
SET @var = 0;

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

## See Also

* [User-defined variables](/docs/server/reference/sql-structure/sql-language-structure/user-defined-variables.md)
* [Information Schema USER\_VARIABLES Table](/docs/server/reference/system-tables/information-schema/information-schema-tables/information-schema-user_variables-table.md)

<sub>*This page is licensed: CC BY-SA / Gnu FDL*</sub>

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