drop table if exists tab; create table tab (id UUID, value UInt32) engine = MergeTree PARTITION BY id order by tuple(); insert into tab values ('61f0c404-5cb3-11e7-907b-a6006ad3dba0', 1), ('61f0c404-5cb3-11e7-907b-a6006ad3dba0', 2); -- Here we check that partition id for UUID partition key did not change. -- Different result means Backward Incompatible Change. Old partitions will not be accepted by new server. select partition_id from system.parts where table = 'tab' and database = currentDatabase(); drop table if exists tab;