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 can cause cluster performance limitations — we recommend using the pt-online-schema-change utility. Learn more in the Changing table structure in MySQL sync clusters with replicas guide;
LOCK/UNLOCK and GET_LOCK()/RELEASE_LOCK() requests are not supported;
all tables must have a primary key, otherwise writes (INSERT) will not be possible;
XA transactions are not supported due to a potential ROLLBACK at the COMMIT; stage;
a transaction may roll back even after a COMMIT — if two transactions modify 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.