How does Error 'You cannot 'ALTER' a log table if logging is enabled' on query happen when running mysql_upgrade? and why?

Last_Error: Error 'You cannot 'ALTER' a log table if logging is enabled' on query. Default database: 'mysql'. Query: 'ALTER

TABLE slow_log ...

Normally when you met above error is because you are running msyql_upgrade on master, subsequently the error happens on the slave.

The solution is:

1.  stop slave;
2. set global slow_query_log = 'OFF';
3. start slave;
4. set global slow_query_log = 'ON';

why does it happen?

When you run mysql_upgrade, it actually contains 'alter table' sql:

ALTER TABLE general_log

   MODIFY event_time TIMESTAMP NOT NULL,

   MODIFY user_host MEDIUMTEXT NOT NULL,

   MODIFY thread_id INTEGER NOT NULL,

   MODIFY server_id INTEGER UNSIGNED NOT NULL,

   MODIFY command_type VARCHAR(64) NOT NULL,

   MODIFY argument MEDIUMTEXT NOT NULL;

ALTER TABLE slow_log

   MODIFY start_time TIMESTAMP NOT NULL,

   MODIFY user_host MEDIUMTEXT NOT NULL,

   MODIFY query_time TIME NOT NULL,

   MODIFY lock_time TIME NOT NULL,

   MODIFY rows_sent INTEGER NOT NULL,

   MODIFY rows_examined INTEGER NOT NULL,

   MODIFY db VARCHAR(512) NOT NULL,

   MODIFY last_insert_id INTEGER NOT NULL,

   MODIFY insert_id INTEGER NOT NULL,

   MODIFY server_id INTEGER UNSIGNED NOT NULL,

   MODIFY sql_text MEDIUMTEXT NOT NULL;

Before running "ALTER TABLE", mysql_upgrade run "set global slow_query_log = 'OFF';", however, this will not be logged into binary log, subsequently "ALTER TABLE" sql are logged, so the slave run "ALTER TABLE" with slow_query_log=ON.