MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6

24.12.10 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 9.4, “User-Defined Variables”.

The user_variables_by_thread table has these columns:

TRUNCATE TABLE is not permitted for the user_variables_by_thread table.