I believe the answer is "yes" but this problem is not unique to semi-sync. Take a single server example: You could ask the database to "COMMIT"; it receives t

I believe the answer is "yes" but this problem is not unique to semi-sync. Take a single server example: You could ask the database to "COMMIT"; it receives the command and processes it, but does not manage to send you notification that it has managed. There is a further failure state: The master could be behind when it crashed. So you need to look at it's gtid executed set or re-image it before plugging it back in. (Not a distributed systems guy; I work on the non HA+replication parts of the server)