alter table performance_schema.setup_objects add column foo integer; ERROR 42000: Access denied for user 'root'@'localhost' to database 'performance_schema' drop table if exists test.setup_objects; create table test.setup_objects as select * from performance_schema.setup_objects; truncate table performance_schema.setup_objects; select count(*) from performance_schema.setup_objects; count(*) 0 insert into performance_schema.setup_objects select * from test.setup_objects; drop table test.setup_objects; ALTER TABLE performance_schema.setup_objects ADD INDEX test_index(OBJECT_NAME); ERROR 42000: Access denied for user 'root'@'localhost' to database 'performance_schema' CREATE UNIQUE INDEX test_index ON performance_schema.setup_objects(OBJECT_NAME); ERROR 42000: Access denied for user 'root'@'localhost' to database 'performance_schema'