Enable a CDC stream for an existing table in Amazon Keyspaces - Amazon Keyspaces (for Apache Cassandra)
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Enable a CDC stream for an existing table in Amazon Keyspaces

To enable a CDC stream for an existing table, you can use the ALTER TABLE statement in CQL, the update-table command with the Amazon CLI, or you can use the console.

For each changed row in the table, Amazon Keyspaces can capture the following changes based on the view_type of the cdc_specification you select:

  • NEW_AND_OLD_IMAGES – both versions of the row, before and after the change. This is the default.

  • NEW_IMAGE – the version of the row after the change.

  • OLD_IMAGE – the version of the row before the change.

  • KEYS_ONLY – the partition and clustering keys of the row that was changed.

For information about how to tag a stream, see Add new tags to a stream.

Note

Amazon Keyspaces CDC requires the presence of a service-linked role (AWSServiceRoleForAmazonKeyspacesCDC) that publishes metric data from Amazon Keyspaces CDC streams into the "cloudwatch:namespace": "AWS/Cassandra" in your CloudWatch account on your behalf. This role is created automatically for you. For more information, see Using roles for Amazon Keyspaces CDC streams.

Cassandra Query Language (CQL)
Enable a stream (CDC stream) with CQL

You can use ALTER TABLE to enable a stream for an existing table.

  1. The following example creates a stream that only captures changes to partition and clustering keys of a changed row.

    ALTER TABLE mykeyspace.mytable
WITH cdc = TRUE
WITH CUSTOM_PROPERTIES={'cdc_specification': {'view_type': 'KEYS_ONLY'}};

  2. To verify the stream settings, you can use the following statement.

    SELECT keyspace_name, table_name, cdc, custom_properties FROM system_schema_mcs.tables WHERE keyspace_name = 'mykeyspace' AND table_name = 'mytable';

    The output of the statement looks similar to this.

     keyspace_name | table_name | cdc  | custom_properties
---------------+------------+------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    mykeyspace |    mytable | True | {'capacity_mode': {'last_update_to_pay_per_request_timestamp': '1741385897045', 'throughput_mode': 'PAY_PER_REQUEST'}, 'cdc_specification': {'latest_stream_arn': 'arn:aws-cn:cassandra:aws-region:111122223333:/keyspace/mykeyspace/table/mytable/stream/2025-03-07T22:20:10.454', 'status': 'ENABLED', 'view_type': 'KEYS_ONLY'}, 'encryption_specification': {'encryption_type': 'AWS_OWNED_KMS_KEY'}, 'point_in_time_recovery': {'status': 'disabled'}}
CLI
Create a CDC stream with the Amazon CLI

  1. To create a stream for an existing table you can use the following syntax.

    aws keyspaces update-table \
--keyspace-name 'mykeyspace' \
--table-name 'mytable' \
--cdc-specification status=ENABLED,viewType=NEW_AND_OLD_IMAGES

  2. The output of that command shows the standard create-table response and looks similar to this example.

    { "resourceArn": "arn:aws:cassandra:us-east-1:111222333444:/keyspace/mykeyspace/table/mytable" }
Console
Enable a CDC stream with the Amazon Keyspaces console

  1. Sign in to the Amazon Web Services Management Console, and open the Amazon Keyspaces console at https://console.amazonaws.cn/keyspaces/home.

  2. In the navigation pane, choose Tables, and then choose a table from the list.

  3. Choose the Streams tab.

  4. Choose Edit to enable a stream.

  5. Select Turn on streams.

  6. Choose View type of the stream. The following options are available. Note that you can't change the view type of a stream after it's been created.

    • New and old images – Amazon Keyspaces captures both versions of the row, before and after the change. This is the default.

    • New image – Amazon Keyspaces captures only the version of the row after the change.

    • Old image – Amazon Keyspaces captures only the version of the row before the change.

    • Primary key only – Amazon Keyspaces captures only the partition and clustering key columns of the row that was changed.

  7. To finish, choose Save changes.