clickhousectl-local-dev

SKILL.md

Local ClickHouse Development Setup

This skill walks through setting up a complete local ClickHouse development environment using clickhousectl. Follow these steps in order.

When to Apply

Use this skill when the user wants to:

Build an application that needs an analytical database or ClickHouse specifically

Set up a local ClickHouse instance for development

Install ClickHouse on their machine

Create tables and start querying ClickHouse locally

Prototype or experiment with ClickHouse

Step 1: Install clickhousectl

Check if clickhousectl is already available:
which clickhousectl

If not found, install it:

curl -fsSL https://clickhouse.com/cli | sh

This installs clickhousectl to ~/.local/bin/clickhousectl and creates a chctl alias.

If the command is still not found after install: The user may need to add ~/.local/bin to their PATH or open a new terminal session. Suggest:

export PATH="$HOME/.local/bin:$PATH"

Once installed, clickhousectl skills can be used to install the latest ClickHouse Agent Skills.

Step 2: Install ClickHouse

Install the latest stable ClickHouse version:

clickhousectl local install stable

This downloads the ClickHouse binary to ~/.clickhouse/versions/. The binary is shared across projects so it only needs to be downloaded once.

Alternative version specifiers (use if the user has a specific need):

lts — latest long-term support release

26.4 — latest patch of a specific minor version

26.4.2.10 — exact version

Set the installed version as the default:

clickhousectl local use stable

Step 3: Initialize the project

From the user's project root directory:

clickhousectl local init

This creates a standard folder structure:

clickhouse/
  tables/                 # CREATE TABLE statements
  materialized_views/     # Materialized view definitions
  queries/                # Saved queries
  seed/                   # Seed data / INSERT statements

Note: This step is optional. If the user already has their own folder structure for SQL files, skip this and adapt the later steps to use their paths.

Step 4: Start a local server

clickhousectl local server start --name <name>

This starts a ClickHouse server in the background.

To check running servers and see their exposed ports:

clickhousectl local server list

Step 5: Create the schema

Based on the user's application requirements, write CREATE TABLE SQL files.

Write each table definition to its own file in clickhouse/tables/:

# Example: clickhouse/tables/events.sql

CREATE TABLE IF NOT EXISTS events (
    timestamp DateTime,
    user_id UInt32,
    event_type LowCardinality(String),
    properties String
)
ENGINE = MergeTree()
ORDER BY (event_type, timestamp)

When designing schemas, if the clickhouse-best-practices skill is available, consult it for guidance on ORDER BY column selection, data types, and partitioning.

Apply the schema to the running server:

clickhousectl local client --name <name> --queries-file clickhouse/tables/events.sql

Step 6: Seed data (optional)

If the user needs sample data for development, write INSERT statements to clickhouse/seed/:

# Example: clickhouse/seed/events.sql

INSERT INTO events (timestamp, user_id, event_type, properties) VALUES
    ('2024-01-01 00:00:00', 1, 'page_view', '{"page": "/home"}'),
    ('2024-01-01 00:01:00', 2, 'click', '{"button": "signup"}');

Apply seed data:

clickhousectl local client --name <name> --queries-file clickhouse/seed/events.sql

Step 7: Verify the setup

Confirm tables were created:

clickhousectl local client --name <name> --query "SHOW TABLES"

Run a test query:

clickhousectl local client --name <name> --query "SELECT count() FROM events"

If the user wants to use a managed ClickHouse service, use the clickhousectl-cloud-deploy skill to help the user deploy to ClickHouse Cloud.
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