Migrating and Modernizing Oracle Databases to PostgreSQL on AWS – Part 2: Assessment

This article details the assessment phase for migrating Oracle databases to PostgreSQL on AWS, demonstrating how to transform discovery inventory into an actionable migration strategy using multi-dimensional analysis.

• Evaluate three interconnected dimensions: structural complexity, performance characteristics, and business criticality to guide migration decisions
• Apply the 7 Rs framework (Refactor, Replatform, Retire, Retain, Rehost, Repurchase, Relocate) to systematically categorize each workload
• Use AWS DMS Schema Conversion to analyze conversion effort; ZCINS found 60% automatic conversion across 42 databases
• Drive Aurora vs. RDS selection from actual I/O metrics (million requests/GB/month) rather than database size alone
• Model full TCO including licensing, infrastructure, DBA costs, and migration expenses; ZCINS achieved 39% savings ($3.5M over 3 years)
• Conduct risk assessment across technical, organizational, data, and schedule categories with specific mitigations
• Produce six deliverables: Migration Readiness Report, Workload Strategy Map, TCO Analysis, Service Selection Matrix, Risk Register, and Complexity Scorecards

Assessment enables data-driven decisions on platform selection, cost optimization, and risk mitigation before execution begins.