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

# ClickHouse destinations

For more information on destinations, see the [Destinations](/destinations) page.

When new data is read from a SaaS instance via a [Read Action](/read-actions) or [Subscribe Action](/subscribe-actions), Ampersand inserts the payload as rows into your ClickHouse table.

## Prerequisites

Before setting up a ClickHouse destination, ensure that you have:

* A ClickHouse instance reachable over HTTPS (ClickHouse Cloud or self-hosted)
* A table to insert into (see [Data format and table setup](#data-format-and-table-setup))
* A username and password with `INSERT` privileges on that table

## Data format and table setup

Ampersand delivers each read or subscribe message as a JSON object. The full payload schema is defined in [webhook.yaml](https://github.com/amp-labs/openapi/blob/main/webhook/webhook.yaml).

ClickHouse matches the payload's top-level keys to your table's columns by name. Create a column for each top-level key you want to store. Keys with no matching column are ignored. `result` is the array of synced records; store it as a JSON string.

```sql theme={null}
CREATE TABLE ampersand_events (
  action         String,
  objectName     String,
  operationId    String,
  installationId String,
  operationTime  String,
  result         String,
  ...
)
ENGINE = MergeTree()
ORDER BY tuple();
```

## Create a ClickHouse destination

Go to the [Destinations page](https://dashboard.withampersand.com/projects/_/destinations) in the Ampersand Dashboard and create a new ClickHouse destination.

You'll need to provide:

| Field                  | Type    | Required | Example                             | Description                                                  |
| ---------------------- | ------- | -------- | ----------------------------------- | ------------------------------------------------------------ |
| **Destination name**   | string  | Yes      | `ampersandClickHouse`               | Alias to reference in your `amp.yaml` file                   |
| **URL**                | string  | Yes      | `https://abc.clickhouse.cloud:8443` | HTTPS URL of your ClickHouse instance                        |
| **Username**           | string  | Yes      | `default`                           | ClickHouse username                                          |
| **Password**           | string  | Yes      |                                     | ClickHouse password                                          |
| **Table name**         | string  | Yes      | `ampersand_events`                  | Table to insert rows into                                    |
| **Database**           | string  | No       | `default`                           | Database containing the table                                |
| **Batch size**         | integer | No       | `1000`                              | Rows to buffer before flushing a batch (defaults to 1000)    |
| **Max wait (seconds)** | integer | No       | `30`                                | Max seconds to wait before flushing a batch (defaults to 30) |

## Refer to the destination in your integration

After creating your ClickHouse destination, reference it in your `amp.yaml` file:

```yaml theme={null}
specVersion: 1.0.0
integrations:
  - name: salesforceToClickHouse
    displayName: Salesforce to ClickHouse
    provider: salesforce
    read:
      objects:
        - objectName: account
          destination: ampersandClickHouse
        - objectName: contact
          destination: ampersandClickHouse
```