I have 2 MySQL servers with row-based replication between them. Both of them are masters and slaves for each other (active-active master-master setup).
If I understand it correctly pt-osc creates triggers to catch any changes while running. But from what I know triggers are not fired in a row-based replication environment. So I guess pt-osc is not able to catch changes made on the second master during the change, is it?
EDIT: While doing some tests and I saw that pt-osc was creating triggers on both masters which would cover changes from both sides. Still I'm quite unsure if I can safely do online changes in this environment.