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altinity-expert-clickhouse-mutations

Diagnose stuck ClickHouse ALTER UPDATE and ALTER DELETE mutations using system.mutations and system.part_log.

16|2|Updated Jan 8, 2026
Search Tags:#performance#monitoring#troubleshooting#diagnose#mutations#clickhouse#database-tuning
One-click install
npx skills add https://github.com/Altinity/Skills --skill altinity-expert-clickhouse-mutations-altinity
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: altinity-expert-clickhouse-mutations
Source: https://github.com/Altinity/Skills/tree/main/altinity-expert-clickhouse/skills/altinity-expert-clickhouse-mutations
Command: npx skills add https://github.com/Altinity/Skills --skill altinity-expert-clickhouse-mutations-altinity

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This Skill tracks and diagnoses ClickHouse mutation operations (ALTER UPDATE, ALTER DELETE, and related mutations) to reduce downtime caused by stuck or slow mutations.

Core Features & Use Cases

  • Mutation tracking across ALTER UPDATE, ALTER DELETE, and other mutation operations.
  • Diagnose root causes: lock contention with merges, replication queues, and part mutations.
  • Performance analysis and actionable recommendations to recover failed or slow mutations.

Quick Start

Analyze the current cluster mutations by querying system.mutations and system.part_log to identify the oldest pending mutations and provide remediation steps.

Frequently Asked Questions about altinity-expert-clickhouse-mutations

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I diagnose stuck ClickHouse mutations?▼

Diagnose stuck ClickHouse mutations by querying system.mutations and system.part_log to identify the oldest pending operations and surface lock contention with merges or replication queue stalls.

Why do ClickHouse ALTER UPDATE and ALTER DELETE operations cause performance bottlenecks?▼

ALTER UPDATE and ALTER DELETE operations cause performance bottlenecks due to lock contention with background merges, replication queue stalls, and part mutation backlogs across multi-node deployments.

How do I monitor ClickHouse mutation backlogs across multi-node clusters?▼

Monitor ClickHouse mutation backlogs across multi-node clusters by tracking pending operations in system.mutations and analyzing part mutation events in system.part_log to compute metrics and surface failure modes.

What is the best way to fix slow ClickHouse mutations blocking replication queues?▼

Fix slow ClickHouse mutations by analyzing system.mutations and system.part_log to identify replication queue stalls and merge contention, then applying targeted performance remediation to clear the backlog.

Does this mutation diagnostic approach work for large multi-node ClickHouse deployments?▼

Yes, this diagnostic approach targets large multi-node ClickHouse deployments by computing metrics across system views to identify mutation backlogs, merge contention, and replication queue stalls.

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