<a id="timescaledb"></a>

# Kafka Connect TimescaleDB (Debezium) SMT Usage Reference for Confluent Cloud

The `TimescaleDb`
(`io.debezium.connector.v2.postgresql.transforms.timescaledb.TimescaleDb`)
open-source Debezium SMT (Single Message Transformation) processes raw change event records captured from
TimescaleDB databases. Use this SMT to perform
logical routing, add relevant metadata, and streamline the handling of
time-series data captured by the Debezium PostgreSQL connector.

For complete details, see the official Debezium
[TimescaleDB SMT](https://debezium.io/documentation/reference/stable/transformations/timescaledb.html)
documentation.

## Limitations

- The `TimescaleDb` SMT is only available for fully-managed Debezium
  PostgreSQL CDC V2 Source connectors.
- The SMT requires a dedicated database connection to the TimescaleDB
  database for metadata lookups. It cannot reuse the connector-level
  database configuration.

## Example

The following example shows how to configure and use the `TimescaleDb`
SMT with a Debezium PostgreSQL CDC V2 Source connector.

```json
"connector.class": "io.debezium.connector.postgresql.PostgresConnector",
"database.hostname": "192.168.99.100",
"database.port": "5432",
"database.user": "postgres",
"database.password": "postgres",
"database.dbname": "postgres",
"topic.prefix": "dbserver1",
"plugin.name": "pgoutput",
"schema.include.list": "_timescaledb_internal",
"transforms": "timescaledb",
"transforms.timescaledb.type": "io.debezium.connector.v2.postgresql.transforms.timescaledb.TimescaleDb",
"transforms.timescaledb.database.hostname": "timescaledb",
"transforms.timescaledb.database.port": "5432",
"transforms.timescaledb.database.user": "postgres",
"transforms.timescaledb.database.password": "postgres",
"transforms.timescaledb.database.dbname": "postgres",
"transforms.timescaledb.target.topic.prefix": "timescaledb",
"transforms.timescaledb.schema.list": "_timescaledb_internal"
```

## Properties

The following table lists the configuration options that you can set for
the SMT.

| Name                  | Description                                                                                         | Type   | Default                 | Importance   |
|-----------------------|-----------------------------------------------------------------------------------------------------|--------|-------------------------|--------------|
| `database.hostname`   | The hostname or IP address of the TimescaleDB metadata server used by the SMT for metadata lookups. | String |                         | High         |
| `database.port`       | The port number of the TimescaleDB metadata server.                                                 | Int    | `5432`                  | High         |
| `database.user`       | The database user for the TimescaleDB metadata connection.                                          | String |                         | High         |
| `database.password`   | The password for the TimescaleDB metadata connection.                                               | String |                         | High         |
| `database.dbname`     | The name of the TimescaleDB database containing the change data.                                    | String |                         | High         |
| `target.topic.prefix` | The namespace prefix for the routed target topics.                                                  | String | `timescaledb`           | Medium       |
| `schema.list`         | Comma-separated list of schema names that contain raw internal<br/>TimescaleDB data tables.         | List   | `_timescaledb_internal` | High         |

## Predicates

Transformations can be configured with *predicates* so that the transformation
is applied only to records which satisfy a condition. You can use predicates in
a transformation chain and, when combined with the [Kafka Connect Filter (Kafka) SMT Usage Reference for Confluent Cloud](filter-ak.md#ak-filter), predicates
can conditionally filter out specific records. For details and examples, see [Predicates](filter-ak.md#predicates).