Limitations of MySQL sync clusters with replicas

MySQL sync clusters with replicas are subject to the following limitations:

replication only works with the InnoDB storage engine (MyISAM is not supported);
ALTER TABLE may cause limitations in cluster operations — we recommend using the pt-online-schema-change utility. Learn more in the Change table structure in a MySQL sync cluster with replicas instructions;
the LOCK/UNLOCK, GET_LOCK()/RELEASE_LOCK() queries are not supported;
all tables must have a primary key — otherwise, writes cannot be performed (INSERT);
XA transactions are not supported due to a possible ROLLBACK at the COMMIT stage;
a transaction may roll back even after COMMIT — of two transactions modifying the same record on different nodes, only one will be completed successfully, 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.