MySQL How to fix mysqldump: Couldn't execute 'FLUSH TABLES': Access denied

MySQL has released an update for mysqldump which causes backups to fail when mysqldump is executed with the flag --single-transaction . The update was released as a minor patch and systems with automatic updates turned on fetched it.

The error message returned when attempting to create a backup using the flag --single-transaction is the following:

mysqldump: Couldn't execute 'FLUSH TABLES': Access denied

There are two solutions at the moment: granting READ and PROCESS permissions to the user executing the backup (recommended) or not using the --single-transaction option (not recommended).

First solution: grant RELOAD & PROCESS privileges (recommended)

This is the recommended solution. You need to run the following two commands in order to grant the privileges:

# Replace my-user with your user and make sure the host matches the user host
GRANT RELOAD, PROCESS ON *.* TO 'my-user'@'%';

# Reload the privileges
FLUSH PRIVILEGES;

In case you need a list with your users and their hosts, you can run the following query:

SELECT `User`, `HOST`, `Process_priv`, `Reload_priv` FROM mysql.user;

Second solution: don't use the --single-transaction flag

This solution is simpler but should be avoided if possible. Running mysqldump without the --single-transaction flag can be problematic because it can result in an inconsistent backup.