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Version: 5.x-preview

Aurora Serverless v2 PostgreSQL Source Setup for VeloDB CDC

This guide covers Aurora Serverless v2 PostgreSQL configuration for CDC (Change Data Capture) synchronization with VeloDB using Flink CDC.

Supported Versions​

DatabaseVersions
Aurora Serverless v2 PostgreSQL13.x, 14.x, 15.x, 16.x

Reference: Aurora PostgreSQL CDC

Enable Logical Replication​

Aurora uses parameter groups instead of direct postgresql.conf editing.

1. Create Parameter Group​

Navigate to RDS > Parameter groups to view existing parameter groups:

Parameter Groups List

Create a custom cluster parameter group with logical replication enabled:

Create Parameter Group

Important: Select DB Cluster Parameter Group as the type (not DB Parameter Group) for Aurora clusters.

aws rds create-db-cluster-parameter-group \
    --db-cluster-parameter-group-name aurora-pg-cdc \
    --db-parameter-group-family aurora-postgresql16 \
    --description "Aurora PostgreSQL with CDC enabled"

aws rds modify-db-cluster-parameter-group \
    --db-cluster-parameter-group-name aurora-pg-cdc \
    --parameters "ParameterName=rds.logical_replication,ParameterValue=1,ApplyMethod=pending-reboot"

Or configure via AWS Console by editing the parameter group and setting rds.logical_replication to 1:

Edit Parameter Group - rds.logical_replication

2. Apply to Cluster​

aws rds modify-db-cluster \
    --db-cluster-identifier your-cluster-name \
    --db-cluster-parameter-group-name aurora-pg-cdc \
    --apply-immediately

3. Reboot Cluster​

Reboot required for rds.logical_replication to take effect:

aws rds reboot-db-instance --db-instance-identifier your-instance-name

Verify Configuration​

SHOW rds.logical_replication;

Expected result:

 rds.logical_replication
-------------------------
 on
(1 row)

User Permissions​

Aurora requires specific roles instead of SUPERUSER attribute.

Create CDC User​

-- Create user (no REPLICATION or SUPERUSER attributes)
CREATE USER cdc_user WITH LOGIN PASSWORD 'your_password';

-- Grant Aurora-specific roles
GRANT rds_replication TO cdc_user;
GRANT rds_superuser TO cdc_user;
GRANT pg_read_all_data TO cdc_user;

-- Grant database-level permissions
GRANT CONNECT ON DATABASE your_database TO cdc_user;
GRANT ALL ON DATABASE your_database TO cdc_user;

-- Grant schema permissions
GRANT USAGE ON SCHEMA public TO cdc_user;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO cdc_user;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO cdc_user;

Required Aurora Roles​

RolePurpose
rds_replicationCreate replication slots and read WAL
rds_superuserManage publications (required for CDC)
pg_read_all_dataRead all tables in all schemas

Note: Aurora master user does NOT have full SUPERUSER privileges. Use roles instead.

Verify User Permissions​

SELECT r.rolname, ARRAY(
    SELECT b.rolname
    FROM pg_catalog.pg_auth_members m
    JOIN pg_catalog.pg_roles b ON (m.roleid = b.oid)
    WHERE m.member = r.oid
) as memberof
FROM pg_roles r
WHERE r.rolname = 'cdc_user';

Expected result:

  rolname  |                     memberof
-----------+--------------------------------------------------
 cdc_user  | {pg_read_all_data,rds_superuser,rds_replication}
(1 row)

Publication Setup​

Create publication as master user (postgres):

-- As postgres user
CREATE PUBLICATION velodb_publication FOR ALL TABLES;

Verify publication:

SELECT * FROM pg_publication WHERE pubname = 'velodb_publication';

Important: Pass --postgres-conf publication.name=velodb_publication to Flink CDC when using Aurora.

REPLICA IDENTITY (Required for DELETEs)​

ALTER TABLE your_table_name REPLICA IDENTITY FULL;

Connection Test​

Verify CDC user can:

  1. Connect:
psql -h your-cluster.cluster-xxxxx.us-west-2.rds.amazonaws.com -p 5432 -U cdc_user -d your_database
  1. List publications:
SELECT * FROM pg_publication;
  1. Read tables:
SELECT COUNT(*) FROM your_table;

Next Steps​

Once Aurora Serverless v2 is configured for CDC, follow the Flink CDC Ingestion Guide to set up real-time sync to VeloDB.

Remember to add --postgres-conf publication.name=velodb_publication when running Flink CDC with Aurora.

Sources​