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 AWS 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.
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)
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Enable a stream (CDC stream) with CQL
You can use ALTER TABLE to enable a stream for an existing table.
-
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'}};
-
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: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
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Create a CDC stream with the AWS CLI
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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
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
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Enable a CDC stream with the Amazon Keyspaces console
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Sign in to the AWS Management Console, and open the Amazon Keyspaces console at https://console.aws.amazon.com/keyspaces/home.
In the navigation pane, choose Tables, and then choose a table from the list.
Choose the Streams tab.
Choose Edit to enable a stream.
Select Turn on streams.
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.
To finish, choose Save changes.
