Clickhouse Table structure replication

Question

I am new to clickhouse and now I work in clickhouse migration, in three node cluster replication i created table structure manually for all replicated nodes where table structure is not replicating to other nodes but other nosql db like MONGODB, table structure also replicating to other nodes.

If we alter table structure we need to do for each node individually.

Is there any possibility to do table structure replication in clickhouse?

Thanks for any suggestion!

Answer 1

You need to use the ON CLUSTER clause in DDL queries to achieve this: https://clickhouse.yandex/docs/en/query_language/create/#distributed-ddl-queries-on-cluster-clause

Answer 2

As I understood your cluster topology is Circular (https://www.altinity.com/blog/2018/5/10/circular-replication-cluster-topology-in-clickhouse) and each node stores two replicas.

Unfortunately, this topology does not support ON CLUSTER-clause. Any modification of table structure is required the execution of SQL-script on each node.