mac workbench が「Table 'performance_schema.session_variables' doesn't exist」

2016年6月、workbenchからmysql突然つながらなくなる
再起動してもダメ、コンソールからはつながる状態、WBさんボケたか

Your connection attempt failed for user 'root' from your host to server at 127.0.0.1:3306:
  Table 'performance_schema.session_variables' doesn't exist

Please:
1 Check that mysql is running on server 127.0.0.1
2 Check that mysql is running on port 3306 (note: 3306 is the default, but this can be changed)
3 Check the root has rights to connect to 127.0.0.1 from your address (mysql rights define what clients can connect to the server and from which machines) 
4 Make sure you are both providing a password if needed and using the correct password for 127.0.0.1 connecting from the host address you're connecting from

5.7.9のBugs Fixedにおいて
performance_schema.session_variablesからgtid_executedが廃止した影響くさい...たぶん

ググってみるとstackoverflowにありました

# mysql_upgrade -u root -p --force
# mysql.server restart

これで解決したくさい...たぶん

2015-10-21のリリースなんだが
なんなんだこの時間差攻撃は