The most common issue when using row-based replication (RBR) is replication lag due to the lack of Primary keys. The problem is that any replicated DML will do a full table scan for each modified row on the replica. This bug report explains it more in-depth: https://bugs.mysql.com/bug.php?id=53375 For example, if a delete is executed on [&]

https://www.percona.com/blog/attack-no-pk-replication-lag-with-mysql-percona-server-8-invisible-columns/