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

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

The `TimescaleDb` SMT (`io.debezium.connector.v2.postgresql.transforms.timescaledb.TimescaleDb`)
processes raw change event records captured from TimescaleDB databases.

## Description

Use the `TimescaleDb` SMT to perform logical routing, add 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. For other topic-routing SMTs, see
[Kafka Connect Single Message Transformations Reference for Confluent Platform](overview.md#connect-transforms-supported).

## Limitations

- The `TimescaleDb` SMT is only available for Debezium PostgreSQL change data
  capture (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.

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

## Properties

The following table lists the configuration options that you can set for the
TimescaleDB integration 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         |

## Example: Route TimescaleDB change events

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

```json
"connector.class": "io.debezium.connector.v2.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"
```

## Predicates

Configure transformations with predicates to ensure they process only records
that satisfy a particular condition. You can also use predicates in a
transformation chain with the [Kafka Connect Filter (Kafka) SMT Usage Reference for Confluent Platform](filter-ak.md#ak-filter) to conditionally filter specific
records. For more information, see [Predicates](filter-ak.md#predicates).