"SHOW EVENTS" fails with "Error Code: 1545. Failed to open mysql.event" I have a MariaDB 5.5.56 install (The default CentOS 7 package).

The VM was running on a host that had some problems reaching its storage. This resulted in the OS remounting some filesystems read-only.

The database is a replication slave and was rebuilt by importing a backup from the master. (After a reboot and fsck, which got the root fs and others back to read-write) (There did not appear to be major data corruption, but replication was failing due to duplicate entries, so restoring seemed safer)

mysqldump failed with mysqldump: Couldn't execute 'show events': Failed to open mysql.event (1545).

Events are not currently in use, but are included in the back, in case they are used in the future.

I have tried running REPAIR TABLE mysql.event, however SHOW EVENTS still fails with Error Code: 1545. Failed to open mysql.event.

SELECT * from mysql.event works as on the master and returns no rows.

On the master (unaffected by the storage issue and running an older, MySQL, version, SHOW EVENTS works as expected and returns no results)

After restarting MariaDB, SHOW TABLES now fails with Error Code: 1577. Cannot proceed because system tables used by Event Scheduler were found damaged at server start. SELECT * from mysql.event still works, returning 0 rows.

mysqlcheck --all-databases --check-upgrade -p returns "OK" for all tables, including mysql.event.
Since mysql.event is empty you can use one of the following two options:
1- use --skip-events to skip events from backup.
2- try to recreate the table (firs you need to drop it):

DROP TABLE IF EXISTS `mysql`.`event`;


if you are using MySQL 5.7

CREATE TABLE `mysql`.`event` (
  `db` char(64) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `name` char(64) NOT NULL DEFAULT '',
  `body` longblob NOT NULL,
  `definer` char(93) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `execute_at` datetime DEFAULT NULL,
  `interval_value` int(11) DEFAULT NULL,
  `interval_field` enum('YEAR','QUARTER','MONTH','DAY','HOUR','MINUTE','WEEK','SECOND','MICROSECOND','YEAR_MONTH','DAY_HOUR','DAY_MINUTE','DAY_SECOND','HOUR_MINUTE','HOUR_SECOND','MINUTE_SECOND','DAY_MICROSECOND','HOUR_MICROSECOND','MINUTE_MICROSECOND','SECOND_MICROSECOND') DEFAULT NULL,
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `modified` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  `last_executed` datetime DEFAULT NULL,
  `starts` datetime DEFAULT NULL,
  `ends` datetime DEFAULT NULL,
  `status` enum('ENABLED','DISABLED','SLAVESIDE_DISABLED') NOT NULL DEFAULT 'ENABLED',
  `on_completion` enum('DROP','PRESERVE') NOT NULL DEFAULT 'DROP',
  `sql_mode` set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','NOT_USED','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION','NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','NO_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40','ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES','STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_DATES','ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER','HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LENGTH') NOT NULL DEFAULT '',
  `comment` char(64) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `originator` int(10) unsigned NOT NULL,
  `time_zone` char(64) CHARACTER SET latin1 NOT NULL DEFAULT 'SYSTEM',
  `character_set_client` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `collation_connection` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `db_collation` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `body_utf8` longblob,
  PRIMARY KEY (`db`,`name`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Events';


MySQL 5.1

Compared to MySQL 5.7, the definer field is smaller.

CREATE TABLE `mysql`.`event` (
  `db` char(64) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `name` char(64) NOT NULL DEFAULT '',
  `body` longblob NOT NULL,
  `definer` char(77) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `execute_at` datetime DEFAULT NULL,
  `interval_value` int(11) DEFAULT NULL,
  `interval_field` enum('YEAR','QUARTER','MONTH','DAY','HOUR','MINUTE','WEEK','SECOND','MICROSECOND','YEAR_MONTH','DAY_HOUR','DAY_MINUTE','DAY_SECOND','HOUR_MINUTE','HOUR_SECOND','MINUTE_SECOND','DAY_MICROSECOND','HOUR_MICROSECOND','MINUTE_MICROSECOND','SECOND_MICROSECOND') DEFAULT NULL,
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `modified` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  `last_executed` datetime DEFAULT NULL,
  `starts` datetime DEFAULT NULL,
  `ends` datetime DEFAULT NULL,
  `status` enum('ENABLED','DISABLED','SLAVESIDE_DISABLED') NOT NULL DEFAULT 'ENABLED',
  `on_completion` enum('DROP','PRESERVE') NOT NULL DEFAULT 'DROP',
  `sql_mode` set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','NOT_USED','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION','NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','NO_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40','ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES','STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_DATES','ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER','HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LENGTH') NOT NULL DEFAULT '',
  `comment` char(64) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `originator` int(10) unsigned NOT NULL,
  `time_zone` char(64) CHARACTER SET latin1 NOT NULL DEFAULT 'SYSTEM',
  `character_set_client` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `collation_connection` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `db_collation` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `body_utf8` longblob,
  PRIMARY KEY (`db`,`name`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Events';


MariaDB 5.5

Compared to MySQL 5.1 the NOT_USED under sql_mode changes to IGNORE_BAD_TABLE_OPTIONS.

CREATE TABLE `mysql`.`event` (
  `db` char(64) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `name` char(64) NOT NULL DEFAULT '',
  `body` longblob NOT NULL,
  `definer` char(77) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `execute_at` datetime DEFAULT NULL,
  `interval_value` int(11) DEFAULT NULL,
  `interval_field` enum('YEAR','QUARTER','MONTH','DAY','HOUR','MINUTE','WEEK','SECOND','MICROSECOND','YEAR_MONTH','DAY_HOUR','DAY_MINUTE','DAY_SECOND','HOUR_MINUTE','HOUR_SECOND','MINUTE_SECOND','DAY_MICROSECOND','HOUR_MICROSECOND','MINUTE_MICROSECOND','SECOND_MICROSECOND') DEFAULT NULL,
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  `modified` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
  `last_executed` datetime DEFAULT NULL,
  `starts` datetime DEFAULT NULL,
  `ends` datetime DEFAULT NULL,
  `status` enum('ENABLED','DISABLED','SLAVESIDE_DISABLED') NOT NULL DEFAULT 'ENABLED',
  `on_completion` enum('DROP','PRESERVE') NOT NULL DEFAULT 'DROP',
  `sql_mode` set('REAL_AS_FLOAT','PIPES_AS_CONCAT','ANSI_QUOTES','IGNORE_SPACE','IGNORE_BAD_TABLE_OPTIONS','ONLY_FULL_GROUP_BY','NO_UNSIGNED_SUBTRACTION','NO_DIR_IN_CREATE','POSTGRESQL','ORACLE','MSSQL','DB2','MAXDB','NO_KEY_OPTIONS','NO_TABLE_OPTIONS','NO_FIELD_OPTIONS','MYSQL323','MYSQL40','ANSI','NO_AUTO_VALUE_ON_ZERO','NO_BACKSLASH_ESCAPES','STRICT_TRANS_TABLES','STRICT_ALL_TABLES','NO_ZERO_IN_DATE','NO_ZERO_DATE','INVALID_DATES','ERROR_FOR_DIVISION_BY_ZERO','TRADITIONAL','NO_AUTO_CREATE_USER','HIGH_NOT_PRECEDENCE','NO_ENGINE_SUBSTITUTION','PAD_CHAR_TO_FULL_LENGTH') NOT NULL DEFAULT '',
  `comment` char(64) CHARACTER SET utf8 COLLATE utf8_bin NOT NULL DEFAULT '',
  `originator` int(10) unsigned NOT NULL,
  `time_zone` char(64) CHARACTER SET latin1 NOT NULL DEFAULT 'SYSTEM',
  `character_set_client` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `collation_connection` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `db_collation` char(32) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL,
  `body_utf8` longblob,
  PRIMARY KEY (`db`,`name`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8 COMMENT='Events';