1. Check the error log for the MySQL 1756 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 any queries are running for a long time:
$ mysqladmin -u root -p processlist
4. Check the MySQL status to see if there are any issues with the server:
$ mysqladmin -u root -p status
5. Check the MySQL variables to see if any of them are set incorrectly:
$ mysqladmin -u root -p variables
6. Check the MySQL user privileges to see if any of them are set incorrectly:
$ mysql -u root -p -e "SELECT * FROM mysql.user;"
7. Check the MySQL database tables to see if any of them are corrupted:
$ mysqlcheck -u root -p --all-databases
8. Check the MySQL replication status to see if any of the slaves are lagging:
$ mysqlrplshow -u root -p
9. Check the MySQL query cache to see if it is enabled and configured correctly:
$ mysql -u root -p -e "SHOW VARIABLES LIKE 'query_cache_%';"
10. Once the issue is identified, fix the MySQL 1756 error by making the necessary changes to the configuration, queries, privileges, etc.11. Finally, use an automated database observability tool to monitor and fix the MySQL 1756 in question. Automated database observability tools can provide real-time insights into the performance and health of the database, allowing for quick and easy identification and resolution of any issues.