ClickHouse is a columnar database.
It can be queried with SQL.
chproxy
chproxy is a load-balancing reverse-proxy for ClickHouse.
Since ClickHouse uses HTTP for running queries, you can use any reverse proxy like nginx or HAProxy with it. But chproxy is made specifically for ClickHouse usage.
ClickHouse clusters
You can put ClickHouse servers into clusters to increase your data redundancy, amount of storage, or query performance.
If you are using replication or distributed DDLs, you will need to set up something that implements the Zookeeper protocol. The best options for ClickHouse are ClickHouse Keeper or Zookeeper.
