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MySQL 8.0 Reference Manual  /  ...  /  Performance Schema User Variable Tables

Pre-General Availability Draft: 2018-03-23

26.11.10 Performance Schema User Variable Tables

The Performance Schema provides a user_variables_by_thread table that exposes user-defined variables. These are variables defined within a specific session and include a @ character preceding the name; see Section 9.4, “User-Defined Variables”.

The user_variables_by_thread table contains these columns:


    The thread identifier of the session in which the variable is defined.


    The variable name, without the leading @ character.


    The variable value.

The user_variables_by_thread table has these indexes:

  • Primary key on (THREAD_ID, VARIABLE_NAME)

TRUNCATE TABLE is not permitted for the user_variables_by_thread table.

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