MySQL 9.6 includes thesys schema, a set of objects that helps DBAs and developers interpret data collected by the Performance Schema.sys schema objects can be used for typical tuning and diagnosis use cases. Objects in this schema include:

For new installations, thesys schema is installed by default during data directory initialization if you usemysqld with the--initialize or--initialize-insecure option. If this is not desired, you can drop thesys schema manually after initialization if it is unneeded.

The MySQL upgrade procedure produces an error if asys schema exists but has noversion view, on the assumption that absence of this view indicates a user-createdsys schema. To upgrade in this case, remove or rename the existingsys schema first.

sys schema objects have aDEFINER of'mysql.sys'@'localhost'. Use of the dedicatedmysql.sys account avoids problems that occur if a DBA renames or removes theroot account.