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

# ALTER SINK

> The `ALTER SINK` command modifies the metadata of a sink.

<Note>
  To modify the SQL definition of a sink, please refer to [Alter a streaming job](/operate/alter-streaming).
</Note>

## Syntax

```sql theme={null}
ALTER SINK sink_name
    alter_option;
```

*`alter_option`* depends on the operation you want to perform on the sink. For all supported clauses, see the sections below.

## Clause

### `OWNER TO`

```sql theme={null}
ALTER SINK sink_name
    OWNER TO new_user;
```

| Parameter or clause | Description                                                                                                   |
| :------------------ | :------------------------------------------------------------------------------------------------------------ |
| **OWNER TO**        | This clause changes the owner of the sink. This will cascadingly change all related internal-objects as well. |
| *new\_user*         | The new owner you want to assign to the sink.                                                                 |

```sql theme={null}
-- Change the owner of the sink named "sink1" to user "user1"
ALTER SINK sink1 OWNER TO user1;
```

### `SET SCHEMA`

```sql theme={null}
ALTER SINK sink_name
    SET SCHEMA schema_name;
```

| Parameter or clause | Description                                             |
| :------------------ | :------------------------------------------------------ |
| **SET SCHEMA**      | This clause moves the sink to a different schema.       |
| *schema\_name*      | The name of the schema to which the sink will be moved. |

```sql theme={null}
-- Move the sink named "test_sink" to the schema named "test_schema"
ALTER SINK test_sink SET SCHEMA test_schema;
```

### `SET PARALLELISM`

```sql theme={null}
ALTER SINK sink_name
SET PARALLELISM { TO | = } parallelism_number;
```

| Parameter or clause | Description                                                                                                                                                                                                                                                                                                                                                                                                                    |
| :------------------ | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **SET PARALLELISM** | This clause controls the degree of [parallelism](/reference/key-concepts#parallelism) for the targeted [streaming job](/reference/key-concepts#streaming-queries).                                                                                                                                                                                                                                                             |
| parallelism\_number | Can be ADAPTIVE or a fixed number (e.g., 1, 2, 3). Setting it to ADAPTIVE expands the job's parallelism to all available units, while a fixed number locks it at that value. Setting it to 0 is equivalent to ADAPTIVE. The maximum allowed value is determined by the `max_parallelism` of the job. For more information, see [Configuring maximum parallelism](/deploy/k8s-cluster-scaling#configuring-maximum-parallelism). |

```sql theme={null}
-- Set the parallelism of the sink "s" to 4.
ALTER SINK s SET PARALLELISM = 4;
```

### `SET BACKFILL_PARALLELISM`

```sql theme={null}
ALTER SINK sink_name
    SET BACKFILL_PARALLELISM { TO | = } parallelism_value [ DEFERRED ];
```

This statement controls the degree of parallelism used during the backfill phase of a sink. It lets you tune resource usage for backfilling independently from the sink's steady-state parallelism.

| Parameter or clause           | Description                                                                                                                                                                      |
| :---------------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **SET BACKFILL\_PARALLELISM** | Sets the parallelism for the backfill phase of the streaming job.                                                                                                                |
| *parallelism\_value*          | Can be `ADAPTIVE` or a fixed number (e.g., 1, 2, 3). Setting it to `ADAPTIVE` or `0` expands backfill parallelism to all available units. A fixed number locks it at that value. |
| **DEFERRED**                  | Optional. When specified, the change takes effect after the current backfill completes, without interrupting an ongoing backfill. If omitted, the change is applied immediately. |

```sql theme={null}
-- Set backfill parallelism to a fixed value
ALTER SINK s1 SET BACKFILL_PARALLELISM = 4;

-- Set backfill parallelism to adaptive
ALTER SINK s1 SET BACKFILL_PARALLELISM = ADAPTIVE;

-- Defer the parallelism change until the current backfill completes
ALTER SINK s1 SET BACKFILL_PARALLELISM = 4 DEFERRED;
```

### `SET SINK_RATE_LIMIT`

```sql theme={null}
ALTER SINK sink_name
    SET SINK_RATE_LIMIT { TO | = } { default | rate_limit_number };
```

Use this statement to modify the rate limit of a sink. For the specific value of `SINK_RATE_LIMIT`, refer to [How to view runtime parameters](/operate/view-configure-runtime-parameters/#how-to-view-runtime-parameters).

```sql Example theme={null}
-- Alter the rate limit of a sink to default
ALTER SINK s1 SET SINK_RATE_LIMIT = default;

-- Alter the rate limit of a sink to 1000
ALTER SINK s1 SET SINK_RATE_LIMIT = 1000;
```

<h3 id="set-backfill-rate-limit">
  `SET BACKFILL_RATE_LIMIT`
</h3>

```sql theme={null}
ALTER SINK sink_name
    SET BACKFILL_RATE_LIMIT { TO | = } { default | rate_limit_number };
```

This statement controls the rate limit of a sink's backfilling process, which reads the historical data of the upstream relation when the sink is created. It is separate from `SINK_RATE_LIMIT`, which throttles writes to the external system. For the specific value of `BACKFILL_RATE_LIMIT`, refer to [How to view runtime parameters](/operate/view-configure-runtime-parameters/#how-to-view-runtime-parameters).

```sql Examples theme={null}
-- Pause the backfill
ALTER SINK s1 SET BACKFILL_RATE_LIMIT=0;

-- Set backfill rate limit to 1000
ALTER SINK s1 SET BACKFILL_RATE_LIMIT=1000;

-- Disable the backfill rate limit
ALTER SINK s1 SET BACKFILL_RATE_LIMIT=DEFAULT;
```

<Note>
  For how the backfill rate limit behaves and how to inspect it, see [Rate limiting](/processing/backfill#rate-limiting).
</Note>

### `SET RESOURCE_GROUP`

```sql theme={null}
ALTER SINK sink_name
    SET RESOURCE_GROUP { TO | = } { DEFAULT | resource_group_name } [ DEFERRED ];
```

```sql theme={null}
ALTER SINK sink_name
    RESET RESOURCE_GROUP [ DEFERRED ];
```

Use this statement to change the resource group used by the sink's streaming job.

| Parameter or clause       | Description                                          |
| :------------------------ | :--------------------------------------------------- |
| **SET RESOURCE\_GROUP**   | Assigns the sink to a specific resource group.       |
| **RESET RESOURCE\_GROUP** | Resets the sink to the default resource group.       |
| *resource\_group\_name*   | The target resource group.                           |
| **DEFERRED**              | Optional. Defers applying the resource group change. |

```sql theme={null}
-- Assign the sink to a resource group
ALTER SINK orders_sink SET RESOURCE_GROUP = high_priority;

-- Reset the sink to the default resource group
ALTER SINK orders_sink RESET RESOURCE_GROUP DEFERRED;
```

### `RENAME TO`

```sql theme={null}
ALTER SINK sink_name
    RENAME TO new_name;
```

| Parameter or clause | Description                               |
| :------------------ | :---------------------------------------- |
| **RENAME TO**       | This clause changes the name of the sink. |
| *new\_name*         | The new name of the sink.                 |

```sql theme={null}
-- Change the name of the sink named "sink0" to "sink1"
ALTER SINK sink0 RENAME TO sink1;
```

### `SWAP WITH`

```sql theme={null}
ALTER SINK name
SWAP WITH target_name;
```

| Parameter      | Description                                        |
| :------------- | :------------------------------------------------- |
| *name*         | The current name of the sink to swap.              |
| *target\_name* | The target name of the sink you want to swap with. |

```sql theme={null}
-- Swap the names of the log_sink sink and the error_sink sink.
ALTER SINK log_sink
SWAP WITH error_sink;
```

### `CONNECTOR WITH`

<Note>
  Added in v2.5.0.
</Note>

```sql theme={null}
ALTER SINK sink_name CONNECTOR WITH (
  'property_name' = 'value',
  ...
);
```

| Parameter          | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| :----------------- | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **CONNECTOR WITH** | Allows you to update connector-specific properties for an existing sink without recreating it.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| property\_name     | The properties vary by connector type: <ul><li>For **ClickHouse**, **DeltaLake**, and **StarRocks**, the supported parameter is `commit_checkpoint_interval`.</li><li>For **Iceberg**, the supported parameter is `commit_checkpoint_interval`.</li><li>For **Kafka**, the supported parameters include: `properties.allow.auto.create.topics`, `properties.batch.num.messages`, `properties.batch.size`, `properties.enable.idempotence`, `properties.max.in.flight.requests.per.connection`, `properties.message.max.bytes`, `properties.message.send.max.retries`, `properties.message.timeout.ms`, `properties.queue.buffering.max.kbytes`, `properties.queue.buffering.max.messages`, `properties.queue.buffering.max.ms`, `properties.reconnect.backoff.ms`, `properties.reconnect.backoff.max.ms`, `properties.request.required.acks`, `properties.retry.backoff.ms`, `properties.retry.backoff.max.ms`, `properties.receive.message.max.bytes`, `properties.socket.connection.setup.timeout.ms`.</li><li>For **OpenSearch**, the supported parameters are `batch_num_messages`, `batch_size_kb`, and `concurrent_requests`.</li><li>For **Pulsar**, the supported parameter is `properties.routing.mode`.</li></ul> |

```sql theme={null}
-- Enable idempotence for the sink
ALTER SINK my_kafka_sink CONNECTOR WITH (
  'properties.enable.idempotence' = 'true'
);

-- Update batching settings for an OpenSearch sink
ALTER SINK my_opensearch_sink CONNECTOR WITH (
  'batch_num_messages' = '500',
  'batch_size_kb' = '4096',
  'concurrent_requests' = '2'
);

-- Change the routing policy of a Pulsar sink
ALTER SINK my_pulsar_sink CONNECTOR WITH (
  'properties.routing.mode' = 'round_robin'
);
```