PostgreSQL and MySQL are both excellent relational databases that power millions of applications. The choice between them is not about which is "better" — it is about which is better suited to your specific requirements, team expertise, and long-term plans. Both have evolved significantly, and the gaps between them have narrowed. Here is an honest comparison to help you decide.
When to Choose PostgreSQL
PostgreSQL has earned its reputation as the more feature-complete database. Choose it when:
- Complex queries and data integrity: PostgreSQL's query planner is more sophisticated, especially for complex joins, subqueries, and window functions. It enforces constraints more strictly, which catches data integrity issues early.
- JSON and semi-structured data: PostgreSQL's JSONB data type allows you to store, index, and query JSON data with native operators. This makes it viable as a hybrid relational/document database, reducing the need for a separate NoSQL store.
- Extensions and advanced types: PostGIS for geospatial data, pg_trgm for fuzzy text search, hstore for key-value pairs, and array types are all built into the PostgreSQL ecosystem. These extensions are production-grade and eliminate the need for additional services.
- Standards compliance: PostgreSQL adheres more closely to the SQL standard, which means queries are more portable if you ever need to switch databases.
When to Choose MySQL
MySQL's strengths lie in simplicity, speed for common operations, and ecosystem breadth:
- Read-heavy workloads: MySQL with InnoDB excels at simple read queries — SELECT by primary key, straightforward JOINs, and read-replica architectures. For applications where 90% of operations are reads, MySQL is fast and predictable.
- WordPress and PHP ecosystems: WordPress, Laravel, Magento, and the majority of PHP applications are designed for MySQL. The tooling, documentation, and community support are deeply integrated.
- Managed hosting availability: Every cloud provider and shared hosting platform supports MySQL. PlanetScale offers a serverless MySQL-compatible database with excellent developer experience. The hosting options are broader than PostgreSQL, though this gap is closing.
Performance Comparison
For simple primary key lookups and basic queries, MySQL and PostgreSQL perform similarly — differences are in single-digit percentage ranges and depend heavily on configuration and hardware. PostgreSQL tends to outperform MySQL on complex analytical queries, queries involving many JOINs, and workloads that mix reads and writes heavily. MySQL tends to be slightly faster for simple read-heavy workloads with proper indexing.
In practice, the performance difference between a well-tuned MySQL and a well-tuned PostgreSQL instance is rarely the deciding factor. Application-level optimisations — proper indexing, query structure, and caching — have a far larger impact than the choice of database engine.
Scalability and Replication
Both databases support replication for read scaling. MySQL's replication is simpler to set up and has been production-proven at massive scale by companies like Facebook and Uber. PostgreSQL's logical replication is more flexible but has historically been more complex to manage. For horizontal write scaling, neither database handles this natively — you need solutions like Citus (PostgreSQL) or Vitess (MySQL) for sharding across multiple nodes.
Our Recommendation
For new projects at Born Digital, we default to PostgreSQL unless there is a specific reason to choose MySQL. Its feature set covers a wider range of requirements, and the trend in the development community strongly favours PostgreSQL — frameworks like Rails, Django, and the Node.js ecosystem have converged on PostgreSQL as the recommended database. For projects built on WordPress, WooCommerce, or existing MySQL codebases, MySQL remains the practical choice. The best database is the one your team knows and can operate reliably in production.