This article provides a comprehensive guide for migrating Aurora PostgreSQL or RDS PostgreSQL databases across AWS accounts with minimal downtime using AWS DMS.

• Use Aurora cloning or RDS snapshot restore for initial data load phase
• Enable logical replication and create replication slots on source database
• Configure AWS DMS CDC-only task for ongoing change data capture
• Capture log sequence number (LSN) from target after initial load
• Use test_decoding plugin for logical replication in AWS DMS
• Disable triggers on target database before replication begins
• Monitor replication lag using CloudWatch metrics and pg_replication_slots
• Enable data validation to verify accuracy of migrated data
• Update sequences and re-enable triggers during cutover phase
• Stop application, verify zero CDC latency, then switch to target database
• Cross-account cloning requires AWS RAM sharing and KMS key policy updates
• Tables must have primary keys for AWS DMS CDC to capture DELETE/UPDATE operations

This migration approach minimizes downtime by combining fast initial data load with continuous replication, enabling near-zero-downtime cutover to the target database.