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

# ClickHouse

> Configure a ClickHouse destination for the GoldRush Pipeline API to batch-insert structured blockchain data.

The ClickHouse destination writes structured pipeline output to a ClickHouse database using batch inserts. It supports configurable buffer sizes and flush intervals for throughput tuning.

## Configuration

```yaml theme={null}
destination:
  type: "clickhouse"
  url: "clickhouse://host:8123/db"
  user: "${CH_USER}"
  password: "${CH_PASSWORD}"
  batch_size: 10000
  flush_interval_ms: 5000
```

### Fields

| Field               | Type   | Required | Default | Description                   |
| ------------------- | ------ | -------- | ------- | ----------------------------- |
| `url`               | string | yes      | --      | JDBC connection URL           |
| `user`              | string | yes      | --      | Database user                 |
| `password`          | string | yes      | --      | Database password             |
| `batch_size`        | int    | no       | 10,000  | Rows per batch insert         |
| `flush_interval_ms` | long   | no       | 5,000   | Max time (ms) between flushes |

## How It Works

1. Rows are buffered in memory as they arrive from the pipeline.
2. When the buffer reaches `batch_size` **or** `flush_interval_ms` elapses since the last flush, a batch `INSERT` executes against the target table.
3. The `INSERT` SQL is dynamically generated from the field names present in each row.
4. All column names are automatically quoted in the generated SQL to handle reserved words.

## Type Coercion

The destination maps pipeline data types to ClickHouse column types as follows:

| Data Type | Database Handling |
| --------- | ----------------- |
| String    | String column     |
| Long      | Int64 / UInt64    |
| Integer   | Int32 / UInt32    |
| Double    | Float64           |
| Boolean   | Bool / UInt8      |
| byte\[]   | Bytes             |
| null      | Null              |