1. Check the error log for the MySQL 1843 error:
$ tail -f /var/log/mysql/error.log
2. Check the MySQL configuration file for any misconfigurations:
$ cat /etc/mysql/my.cnf
3. Check the MySQL process list to see if there are any processes that are running that shouldn't be:
$ mysqladmin -u root -p processlist
4. Check the MySQL user table to see if there are any users that shouldn't have access:
$ mysql -u root -p -e "SELECT * FROM mysql.user;"
5. Check the MySQL privileges table to see if there are any privileges that shouldn't be granted:
$ mysql -u root -p -e "SELECT * FROM mysql.user_privileges;"
6. Check the MySQL grant tables to see if there are any grants that shouldn't be granted:
$ mysql -u root -p -e "SELECT * FROM mysql.grant_tables;"
7. Check the MySQL system variables to see if there are any variables that are set incorrectly:
$ mysql -u root -p -e "SHOW VARIABLES;"
8. Check the MySQL system status to see if there are any issues that need to be addressed:
$ mysql -u root -p -e "SHOW STATUS;"
9. Once all of the above steps have been completed, it is recommended to use an automated database observability tool to monitor and fix the MySQL 1843 in question. This tool can provide real-time insights into the performance and health of the database, as well as alerting when any issues arise. This can help to quickly identify and fix any issues that may arise, as well as prevent any future issues from occurring.