In part 1 we looked at the open-source ClickHouse architecture, in part 2 we dive into the serverless architecture of ClickHouse Cloud.

The serverless ClickHouse architecture

ClickHouse Cloud is an entirely serverless offering of ClickHouse that uses a new MergeTree engine called the SharedMergeTree. Where a traditional on-premise ClickHouse cluster is composed of a set of monolithic servers that do both query processing and storage, CH Cloud servers separate storage and compute, with the servers being stateless compute instances and storage served solely by cloud object storage. The SharedMergeEngine is at the core of this serverless architecture.

See The Architecture of Serverless Data Systems introduction chapter to find other serverless data systems. This chapter is the first system of group 3 - the analytics database group.

ClickHouse is an open-source, column-oriented, distributed (real-time) OLAP database management system. ClickHouse Cloud offers serverless Clickhouse clusters, billed according to the compute and storage resources consumed. 

Before we jump into the architecture of ClickHouse Cloud, it’s worth understanding the architecture of a standard ClickHouse cluster first. The storage architecture of ClickHouse plays a critical role in how the serverless version was designed. Part 1 of this chapter will focus on the standard, fully open-source ClickHouse, and part 2 will focus on the serverless architecture of ClickHouse Cloud.