Note: This project was developed in a professional environment. Source code is private, so this case study focuses on architecture, process, and outcomes.
Problem
The business needed to migrate from MySQL to PostgreSQL to improve long-term performance, data integrity, and maintainability. The challenge was that the system could not be taken offline—the migration had to happen while the business was actively operating.
Constraints
- Live production environment: users were actively using the system.
- Zero data loss requirement.
- Different database engines with schema and data-type differences.
- Rollback had to be possible at any point.
Solution
I designed an automated migration process that allowed data to be transferred from MySQL to PostgreSQL while the application remained operational. The process relied on scripted exports, controlled imports, and validation checkpoints to ensure consistency between both databases before final cutover.
High-level approach
- Schema preparation: adapt schemas and data types for PostgreSQL compatibility.
- Initial data migration: bulk transfer historical data from MySQL to PostgreSQL.
- Live delta sync: re-run migrations to capture changes made while the business was active.
- Validation: compare row counts and critical tables between both databases.
- Cutover: switch application configuration to PostgreSQL during a controlled window.
- Rollback readiness: MySQL remained intact until PostgreSQL was fully validated.
Key decisions
- Live migration strategy: avoided business downtime by syncing data incrementally.
- Automation: reduced manual steps during a high-risk operation.
- Validation gates: no cutover until consistency checks passed.
- Rollback-first mindset: the ability to revert was designed before execution.
Impact
- Successfully migrated from MySQL to PostgreSQL with no business interruption.
- Maintained data integrity during live operations.
- Reduced long-term maintenance complexity and improved database reliability.
What I learned
- Planning and executing database migrations in live environments.
- Managing risk when changing core infrastructure components.
- Communicating clearly with stakeholders during high-impact changes.