Unable to login Plesk: 1015 Can't lock file (errno: 165 - Table is read only)

Symptoms

• Unable to open Plesk with the following error:

  CONFIG_TEXT: ERROR: Plesk\Exception\Database: DB query failed: SQLSTATE[HY000]: General error: 1015 Can't lock file (errno: 165 - Table is read only), query was: DELETE FROM `SessionContexts` WHERE (`sessionId` IN (SELECT `sessions`.`sess_id` FROM `sessions` WHERE (`modified` + `lifetime` < 1522082154)))

• The same error is shown using plesk login command:

  # plesk login
  ERR [panel] Cannot save cli call statistic DB query failed: SQLSTATE[HY000]: General error: 1015 Can't lock file (errno: 165 - Table is read only), query was: INSERT CliCallsStat (`util`, `command`, `lastExecutionDateTime`) VALUES (:util, :command, now()) ON DUPLICATE KEY UPDATE `count` = `count` + 1, `lastExecutionDateTime` = now()
  DB query failed: SQLSTATE[HY000]: General error: 1015 Can't lock file (errno: 165 - Table is read only), query was: INSERT INTO password_secrets (secret, type, id, created) VALUES ("", "1", "", now());
  exit status 1

• MySQL configuration includes parameter innodb_force_recovery at level 4 or higher.

  # grep -r innodb_force_recovery /etc/my*
  /etc/mysql/my.cnf:innodb_force_recovery = 6

Cause

InnoDB databases were in a non-finished recovery process, what causes InnoDB to be set in read-only mode according to MySQL Official Documentation.

Resolution

Complete InnoDB Databases recovery using the article How to fix InnoDB corruption cases for the MySQL database?