Oracle to PostgreSQL migration: approach and risk

The key question

A successful migration preserves the business behaviour that matters. That covers more than data types and tables: database logic, application code, privileges and operations all need to fit together.

What to inventory

• Inventory objects and schemas, PL/SQL, jobs and interfaces.
• Mark Oracle-specific functions and dynamic SQL.
• Define data volume, change rate and acceptable interruption.

Design the target deliberately

Separate feasibility, target architecture, conversion, data movement and acceptance. A pilot should cover one complete business process with critical dependencies. Conversion tooling can reduce effort, but generated output still needs behavioural validation.

A concrete validation step

Before the pilot, state what result would change the target decision. If a critical interface cannot be replaced at acceptable effort, the roadmap must be allowed to change.

Evidence required before sign-off

• Reconcile data using business comparison rules.
• Test NULL, time, rounding and sort behaviour.
• Test concurrency, transactions and privileges.
• Plan cutover and rollback with both application and operations teams.