Limitations of MySQL sync clusters with replicas

MySQL sync clusters with replicas are subject to restrictions:

replication works only with the InnoDB storage subsystem (MyISAM is not supported);
ALTER TABLE can cause limitations in cluster operation - we recommend using the utility pt-online-schema-change. Read more in the instructions Changing table structure in MySQL sync cluster with replicas;
LOCK/UNLOCK, GET_LOCK()/RELEASE_LOCK() requests are not supported;
all tables must have a primary key - otherwise it is impossible to make an INSERT record;
XA transactions are not supported due to a possible ROLLBACK during the COMMIT phase;
transaction can rollback even after COMMIT - out of two transactions modifying the same record on different nodes, only one will be successfully completed and the other will be aborted at the cluster level;
When naming temporary tables, do not use names that match the names of permanent tables - such a match will stop replication of the permanent table.