ClickHouse Certified study guide

ClickHouse Certified · Work through your exam, one topic at a time.

The ClickHouse Certified credential is an independent study target for engineers, analysts, and data platform specialists who work with ClickHouse, the fast open-source OLAP database for real-time analytics. This page is an unofficial preparation resource built by an independent study platform; it is not affiliated with, endorsed by, or sponsored by ClickHouse, Inc., and it does not reproduce any commercial question bank. The ClickHouse Certified study guide has 6 sections and about 2,926 words.

ClickHouse Fundamentals and OLAP Concepts

This domain tests the mental model the rest of the exam rests on: how ClickHouse physically stores rows as columns, why its index only helps sorted data, how parts and merges behave, and which OLAP guarantees it does and does not give you. Expect questions that ask you to predict whether a query will be fast, or why a design falls over at scale.

515 words, about 3 min 02

Data Modeling and Table Engines

This domain covers the decisions that fix a table's performance for its lifetime: engine family, sorting key, partitioning, data types and codecs, plus the replication/distribution topology. Questions typically present a workload - deduplicating events, additive metrics, update streams - and ask which engine or key design fits.

440 words, about 2 min 03

Querying with SQL

This domain tests ClickHouse's SQL dialect: filtering stages, aggregation and window idioms, join strictness and direction, cluster-aware constructs, and per-query settings. Expect questions that hand you a query and ask why it is slow, wrong, or non-deterministic.

493 words, about 2 min 04

Ingestion and Integrations

This domain covers getting data in without creating a part explosion: batch sizing, formats, deduplication on retries, streaming engines, file and object-storage ingestion, materialized views as pipelines, and Cloud-specific tooling. Questions usually describe a pipeline and ask what breaks under retry, restart, or high insert frequency.

464 words, about 2 min 05

Performance Tuning and Optimization

This domain tests whether you can find where a query spends time and fix the cause rather than raise a limit. Questions give a symptom - huge read rows, memory spikes, slow joins, too many parts - and ask for the highest-leverage change and the evidence that it worked.

530 words, about 3 min 06

Operations, Security, and ClickHouse Cloud

This domain covers running ClickHouse safely: SQL-driven access control, network and encryption posture, replication and backup mechanics, mutation semantics, monitoring surfaces, and how Cloud differs from self-managed. Questions often describe an operational requirement - isolate a tenant's rows, restore a table, wait for a mutation - and ask for the correct construct or the caveat.

484 words, about 2 min