To connect RisingWave to an AWS RDS or Aurora PostgreSQL database for Change Data Capture (CDC), you need to configure your database to support logical replication.

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1. Enable logical replication

Create or modify a custom parameter group for your database instance and set the following parameters:
  • rds.logical_replication: Set to 1. This enables logical replication on the instance.
  • wal_level: This should automatically be set to logical when rds.logical_replication is enabled. You can verify this setting.
For Aurora PostgreSQL, it is also recommended to set rds.logical_wal_cache to 0 to avoid a known data loss issue affecting certain versions (e.g., 14.5, 13.8, 12.12, 11.17).If you plan to create multiple CDC sources, ensure max_wal_senders is greater than or equal to the number of sources.

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2. Apply the parameter group

Modify your RDS or Aurora instance to use the newly configured parameter group. This change typically requires a reboot of the database instance to take effect.

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3. Grant required privileges

Connect to your database and grant the rds_replication role to your user. This role provides the necessary permissions to manage logical replication slots and stream data. 
GRANT rds_replication TO <user_name>;
You also need to grant standard access privileges to the schemas and tables you want to capture: 
-- Grant connection access to the database
GRANT CONNECT ON DATABASE <database_name> TO <user_name>;

-- Grant usage on the schema
GRANT USAGE ON SCHEMA <schema_name> TO <user_name>;

-- Grant select on all tables in the schema
GRANT SELECT ON ALL TABLES IN SCHEMA <schema_name> TO <user_name>;
-- To grant access to future tables in the schema automatically:
ALTER DEFAULT PRIVILEGES IN SCHEMA <schema_name> GRANT SELECT ON TABLES TO <user_name>;

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Next step

Now that your database is configured, you can proceed to connect RisingWave. ➡️ Connect to PostgreSQL CDC