clickhouse-io

A collection of patterns for ClickHouse, a database designed for fast analysis of large amounts of data. It covers table design, query tuning, data pipelines, and engine selection.

In plain words
What is it for?
Use it to design ClickHouse tables, optimize analytical queries, choose table engines, and build batch or streaming data pipelines.
Why use it?
It helps avoid slow queries and inefficient data storage when working with analytical workloads.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/cloudnative-co/claude-code-starter-kit/clickhouse-io
Any agent
npx skills add cloudnative-co/claude-code-starter-kit --skill clickhouse-io
Clone the repo
git clone --depth 1 https://github.com/cloudnative-co/claude-code-starter-kit

Made for: Claude Code, Codex.

Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 415 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00026 $0.00415
Opus 5 $0.00013 $0.00208
Sonnet 5 $0.00005 $0.00083
Haiku 4.5 $0.00003 $0.00042

Measured 3d ago against content hash 2191873ebf1a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

clickhouse-io scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/clickhouse-io/SKILL.md · 36 lines

What it actually says

ClickHouse Analytics Patterns

ClickHouse is a column-oriented DBMS for OLAP, optimized for fast analytical queries on large datasets. Key strengths: columnar storage, compression, parallel execution, distributed queries, real-time analytics.

Reference Files

File Contents
references/table-design.md MergeTree engine types, table creation patterns, partitioning, ordering keys, data type selection
references/query-optimization.md Filtering best practices, aggregations, window functions, materialized views, performance monitoring
references/data-pipeline.md Bulk/streaming insert, ETL/CDC patterns, time series, funnel, cohort, and retention query templates

Engine Selection Guide

Engine Use When Trade-off
MergeTree Default for most tables No dedup or pre-aggregation
ReplacingMergeTree Data has duplicates from multiple sources Dedup only on merge, not query time
AggregatingMergeTree Pre-computed rollups (hourly/daily stats) Requires *State/*Merge function pairs

Core Rules

  • Batch inserts -- never insert row-by-row
  • Specify columns -- avoid SELECT *
  • Filter on indexed columns first -- match ORDER BY key order
  • Denormalize -- minimize JOINs for analytical tables
  • Leverage materialized views -- for real-time aggregations

ClickHouse excels at analytical workloads. Design tables for your query patterns, batch inserts, and leverage materialized views for real-time aggregations.

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 36 lines · 26 tokens per session scan A 2191873ebf1a

Subscribe to this mod's changes

clickhouse-io is a skill published in the GitHub repository cloudnative-co/claude-code-starter-kit (147 stars, last pushed 10d ago), licensed MIT. It adds 26 tokens to every session and 415 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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