29.12.10 Performance Schema User-Defined 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 11.4, “User-Defined Variables”.

The user_variables_by_thread table has these columns:

• 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.

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.