> ## Documentation Index
> Fetch the complete documentation index at: https://www.propeldata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Federation to ClickHouse

> Query data from self-hosted or ClickHouse Cloud from Propel.

<div />

Federation to ClickHouse enables you to query your self-hosted or ClickHouse Cloud tables without syncing them to Propel.

<Card title="Get started with Federation to ClickHouse" icon="link" href="/docs/federation/clickhouse/setup">
  Step-by-step instructions to connect your ClickHouse server to Propel for federation.
</Card>

## Architecture

Federated ClickHouse Data Pools make queries directly to a table in your own ClickHouse and then serve the data via the SQL, API, or UI components.

<img src="https://mintcdn.com/propeldocs/QOy5SmMMP2AzzqCU/images/docs/clickHouse-architecture-diagram-docs.svg?fit=max&auto=format&n=QOy5SmMMP2AzzqCU&q=85&s=38a148fabf4fefdc4d71c510c0a23b19" alt="ClickHouse with Propel Architecture" width="1100" height="301" data-path="images/docs/clickHouse-architecture-diagram-docs.svg" />

## Features

Federated ClickHouse Data Pools supports the following features:

| Feature name           | Supported | Notes                                                                      |
| ---------------------- | --------- | -------------------------------------------------------------------------- |
| Read-through           | ✅         | Reads through a ClickHouse table. The Propel user needs SELECT privileges. |
| API configurable       | ✅         | See [Management API](/docs/management-api) docs.                           |
| Terraform configurable | ✅         | See [Propel Terraform](/docs/terraform/overview) docs.                     |

## How does the Federation to ClickHouse work?

Federated ClickHouse Data Pools query a table in your ClickHouse database using a set of credentials. The user provisioned for Propel must have at least `SELECT` privileges that ensure real-time access to data.

Once created, a Federated ClickHouse Data Pool is queryable via [SQL](/docs/sql-reference/), the [Query APIs](/docs/query-apis/), or [Embeddable UI](/docs/embeddable-ui), like any other Data Pool.

## Schema changes

When you make changes to the underlying table, you can pick up those changes by creating a new Data Pool.

## Limitations

* Propel only supports connecting via the ClickHouse HTTPS interface.