Setup & maintenance

Learn how to set up, deploy, monitor, and backup ClickHouse with step-by-step guides.
S3 & object storage

AggregateFunction(uniq, UUID) doubled after ClickHouse upgrade

Page description for heading and indexes.

Can not connect to my ClickHouse server

Can not connect to my ClickHouse server.

cgroups and kubernetes cloud providers

cgroups and kubernetes cloud providers.

ClickHouse and different filesystems

ClickHouse and different filesystems.

Transformation Clickhouse logs to ndjson using

ClickHouse operator

Compatibility layer for clickhouse-operator metric exporter

Page description for heading and indexes.

How to convert uniqExact states to approximate uniq functions states

A way to convert to uniqExactState to other uniqStates (like uniqCombinedState) in Clickhouse.

Custom Settings

Using custom settings

Description of asynchronous_metrics

Clickhouse data/disk encryption (at rest)

Example how to encrypt data in tables using storage policies.

How ALTER's works in ClickHouse

How to recreate a table in case of total corruption of the replication queue

How to recreate a table in case of total corruption of the replication queue.

http handler example


Logging configuration and issues

Precreate parts using clickhouse-local

Precreate parts using clickhouse-local.

Access Control and Account Management (RBAC)

Access Control and Account Management (RBAC).


Recovery after complete data loss

Replication: Can not resolve host of another clickhouse server

source parts size is greater than the current maximum

source parts size (…) is greater than the current maximum (…)

Successful ClickHouse deployment plan

Successful ClickHouse deployment plan.

sysall database (system tables on a cluster level)

Timeouts during OPTIMIZE FINAL

Timeout exceeded ... or executing longer than distributed_ddl_task_timeout during OPTIMIZE FINAL.

Useful settings to turn on/Defaults that should be reconsidered

Useful settings to turn on.

Who ate my CPU

Queries to find which subsytem of Clickhouse is using the most of CPU.

ZooKeeper session has expired

ZooKeeper session has expired.

Aggressive merges

Altinity packaging compatibility >21.x and earlier

AWS EC2 Storage

AWS EBS, EFS, FSx, Lustre

ClickHouse in Docker

ClickHouse Monitoring

ClickHouse versions


clickhouse-backup + backblaze

Converting MergeTree to Replicated

Data Migration


differential backups using clickhouse-backup

High CPU usage

Load balancers

memory configuration settings

Memory Overcommiter

Enable Memory overcommiter instead of ussing max_memory_usage per query

Moving a table to another device.

Object consistency in a cluster

Production Cluster Configuration Guide

Replication queue

Schema migration tools for ClickHouse

Server config files

How to manage server config files in Clickhouse

Settings to adjust

Shutting down a node

SSL connection unexpectedly closed

Suspiciously many broken parts

Suspiciously many broken parts error during the server startup.

System tables ate my disk


Who ate my memory

X rows of Y total rows in filesystem are suspicious


Last modified 2022.02.18: Update (11a4a82)