How To Enable CDC With Postgres On Amazon RDS

Change Data Capture (CDC) allows organizations to track real-time changes in their databases by enabling timely data integration and analytics. In this article will explain the steps to enable CDC in your Amazon RDS PostgreSQL instance, covering configuration, replication slot creation, and setting up publications and subscriptions.

How To Enable CDC With Postgres On Amazon RDS

To enable Change Data Capture (CDC) with PostgreSQL on Amazon RDS, there are several configuration steps involved. This process ensures our database is set up for real-time change tracking and Using PostgreSQL logical replication features. By following these steps, we can capture data changes for integration or analytics purposes without downtime.

1. Changing PostgreSQL Parameters

2. Creating a Replication Slot

3. Setting Up a Publication

4. Setting Up a Subscription

5. Monitoring Changes

6. Clean Up

Prerequisites

• You have an active AWS account.
  
• There is an Amazon RDS instance running PostgreSQL.
  
• Basic understanding of SQL and PostgreSQL.

Steps to How To Enable CDC With Postgres On Amazon RDS

Step 1: Change PostgreSQL Parameters

Access the AWS Management Console

1. Log into the AWS Management Console.
   
2. Navigate to RDS and select your PostgreSQL instance.
   
3. On the left sidebar, click on Parameter Groups.
   
4. After changing the parameters, assign the parameter group to RDS instance and reboot the instance to apply the changes.

Modify the Required Parameters

• Create a new parameter group or choose an existing one.
  
• Modify the following parameters to enable logical replication for CDC:

  Parameter	Value
  wal_level	logical
  max_replication_slots	Greater than 0 (e.g. 4)
  max_wal_senders	Greater than 0 (e.g. 5)

Step 2: Create a Replication Slot

A replication slot is required to capture logical changes in the database. Follow the steps below to create one:

Connect to PostgreSQL

Use an SQL client like pgAdmin or psql to connect to your PostgreSQL instance.

Create Logical Replication Slot

This command creates a logical replication slot that will track changes using the test_decoding plugin. Run the following command to create a replication slot:

SELECT * FROM pg_create_logical_replication_slot('your_slot_name', 'test_decoding'); 

Output:

Step 3: Set Up a Publication

Create a Publication

A publication allows you to track changes from specific tables. This publication will track changes to the specified table (table_name). Run the following command to create a publication:

CREATE PUBLICATION your_publication_name FOR TABLE your_table_name;

Step 4: Set Up a Subscription (Optional)

If you want to replicate changes to another PostgreSQL database, you need to set up a subscription in the target database.

Connect to the Target Database

Use an SQL client to connect to the target PostgreSQL database.

Create the Subscription

This command establishes a subscription that replicates changes from the source database based on the specified publication. Run the following command to set up a subscription:

CREATE SUBSCRIPTION your_subscription_name CONNECTION 'host=source_host dbname=your_db user=your_user password=your_password' PUBLICATION your_publication_name;

Output:

CREATE SUBSCRIPTION

Step 5: Monitor Changes

Once everything is set up, you can monitor changes captured by the replication slot.

View Captured Changes

Run the following command to view the changes captured by the replication slot:

SELECT * FROM pg_logical_slot_get_changes('your_slot_name', NULL, NULL);

Output:

Step 6: Clean Up (Optional)

If you no longer need the replication setup, you can remove the replication slot and publication.

Remove Replication Slot

Run the following command to drop the replication slot:

SELECT pg_drop_logical_replication_slot('your_slot_name');
DROP PUBLICATION your_publication_name;

Drop Publication

Run this command to drop the publication:

DROP PUBLICATION your_publication_name;

Conclusion

Implementing Change Data Capture on PostgreSQL in Amazon RDS enhances data availability and responsiveness. By following the outlined steps, you can efficiently monitor and capture data. The real-time capability enhances data integration and responsivity. It allow our business make current decisions based on the latest information available.