ClickHouse Keeper Archives | ChistaDATA Inc.

ClickHouse High Availability Architecture on 26.9: A Definitive 5-Layer Framework for Safe Failover

A ChistaDATA point of view on ClickHouse high availability architecture for 26.9: zone-level topology, Keeper quorum placement, zero-downtime rolling upgrades and measured disaster recovery outcomes.

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ClickHouse High Availability on 26.9: 8 Brutal Failure Drills, Measured

ChistaDATA Inc.

ClickHouse high availability on 26.9, tested: we broke a three-replica cluster with ClickHouse Keeper eight ways and measured what survived, with the SQL and runbooks our ClickHouse support team uses.

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Advanced ClickHouse Troubleshooting on 26.8 LTS: 9 Proven Techniques for Slow Queries, Stuck Merges and Memory Errors

ChistaDATA Inc.

The ClickHouse troubleshooting method ChistaDATA uses on 26.8 LTS and 26.9: nine techniques, the system tables behind each, the queries we run, and one disk-full incident from our own lab.

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ClickHouse Performance Settings in 26.8 LTS: 14 Proven Changes

ChistaDATA Inc.

The ClickHouse performance settings that changed between 26.3 LTS and 26.8 LTS: what each default does to ingest, aggregation, joins and distributed execution, how to measure it, and the rollout method we use.

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ClickHouse Troubleshooting Techniques: 8 Proven Drills We Teach

ChistaDATA Inc.

The ClickHouse troubleshooting techniques taught in CHT-400 at ChistaDATA University: a scope, prove, fix method and the diagnostic queries for eight production incidents, from too many parts to distributed timeouts.

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ClickHouse certification and competency ladder at ChistaDATA University: CHT-100 to CHT-300 core levels, CHT-400 and CHT-500 specialist programmes, CHT-900 executive track, and the three certification tiers

ClickHouse Certification at ChistaDATA University: 3 Proven Tiers

ChistaDATA Inc.

How ChistaDATA University builds ClickHouse certification on a competency ladder: CHT-100 to CHT-900 programmes, real lab code, failure drills, a live-cluster capstone defence, corporate and academic delivery, and how to start.

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ClickHouse 26.8 LTS: 7 Essential Performance and HA Changes

ChistaDATA Inc.

ClickHouse 26.8 LTS read for production: adaptive aggregation, IEJoin, plan-based parallel replicas, Keeper on disk, always_fetch_mutated_part, and the 26.3 to 26.8 breaking-change checklist for self-managed and Cloud.

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Real-Time Analytics for Consumer Goods: 4 Proven ClickHouse + Kafka Patterns

ChistaDATA Inc.

Real-time analytics for consumer goods is now a two-component problem: Apache Kafka 4.3 as the event backbone and ClickHouse 26.8 LTS as the serving engine. This paper is the design we put in front of […]

ClickHouse 26.8 LTS: What’s New for Real-Time Analytics (Tested)

ChistaDATA Inc.

ClickHouse 26.8 shipped on 27 August 2026 as the second LTS line of the year, and two days later the 25.8 LTS line dropped out of support. If you run 25.8 in production, you are […]

ClickHouse Sharding Troubleshooting and Performance Optimization

ChistaDATA Inc.

A field guide to ClickHouse sharding troubleshooting: Distributed send-queue backlogs, duplicate rows from internal_replication, shard skew, initiator merge bottlenecks, distributed JOIN failures and unavailable shards, each with the system.* evidence, the mechanism, the staged fix, and the alert that catches it early.

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