Recently, my friend Marco Tusa(MySQL Daddy or the Grinch) wrote his first impression on MySQL Group Replication (part of InnoDB Cluster). And his conclusion was not that positive. But when I analyze his setup, I understand that his assumptions were not so right.
Let's try to explain what were the issues and why his test wasn't correct.
Before commenting Marco's tests, I would like to clarify the flow-control implementation in Group Replication:
We designed the flow-control feature in Group Replication as a safety measure for delaying writer nodes when they consistently exceed the write capacity of the Group, so that a large backlog would not make it hard to switch over from a member to another.
Flow-control is …[Read more]