You are viewing the documentation of an older version of the TiDB database (TiDB v5.4). It is recommended that you use the latest LTS version of the TiDB database.
The SHOW PROFILES statement currently only returns an empty result.
ShowStmt:

SHOW PROFILES;
Empty set (0.00 sec)
This statement is included only for compatibility with MySQL. Executing SHOW PROFILES always returns an empty result.