Error appears during start of mysql service: Missing system table mysql.roles_mapping; please run mysql_upgrade to create it

Symptoms

• The following error appears in Plesk while starting mysql service:

  PLESK_ERROR: ERROR: Plesk\Exception\Database: DB query failed: SQLSTATE[HY000]: General error: 1 Can't create/write to file '/var/tmp/#sql_5f1_0.MAI' (Errcode: 2), query was: DESCRIBE `sessions`
  Additionally, an exception has occurred while trying to report this error: Zend_Exception
  No entry is registered for key 'translate' (Mysql.php:53)

• The following error is present in system log (/var/log/messages, /var/log/syslog, /var/log/mariadb/mariadb.log, /var/log/mysql/mysql.log,
  %plesk_dir%MySQL\Data\<SERVER_NAME>.err):

  CONFIG_TEXT: [ERROR] Missing system table mysql.roles_mapping; please run mysql_upgrade to create it

  or:

  CONFIG_TEXT: InnoDB: Error: Fetch of persistent statistics requested for table "table_name"."database_name" but the required system tables mysql.innodb_table_stats and mysql.innodb_index_stats are not present or have unexpected structure. Using transient stats instead.

  or:

  CONFIG_TEXT: InnoDB: Recalculation of persistent statistics requested for table `database_name`.`table_name` but the required persistent statistics storage is not present or is corrupted. Using transient stats instead. For more information, see Help and Support Center at http://www.mysql.com.

• Website shows 'Error establishing a database connection' error and trying to access website databases at Plesk > Domains > example.com > Databases results in the error:

  PLESK_ERROR: Unknown column 'Event_priv' in 'field list

• As a result of errors, MySQL consumes a lot of CPU.

Cause

Failed MySQL upgrade or corrupted installation.

Resolution

1. Connect to the server using SSH/RDP;

2. Complete the MySQL upgrade or re-create missing system tables using the following command:

   On Linux:

   # mysql_upgrade -u admin -p`cat /etc/psa/.psa.shadow` --force

   On Windows

   C:\> "C:\Program Files\MySQL\MySQL Server 5.7\bin\mysql_upgrade.exe" -uadmin -P3306 -p mysql_admin_password