PostgreSQL vs MySQL: Choosing Your Production Database

PostgreSQL 17, released in 2025, continues the project's trajectory as the most feature-rich open-source database available. Its JSONB data type provides document-database capabilities within a relational engine, enabling teams to mix structured and semi-structured data without running a separate NoSQL store. PostgreSQL supports advanced indexing (GIN, GiST, BRIN, and bloom filters), partial indexes, expression indexes, and covering indexes that allow sophisticated query optimization. The extension ecosystem is one of PostgreSQL's greatest strengths: PostGIS for geospatial data, pgvector for AI embedding similarity search, TimescaleDB for time-series workloads, and Citus for horizontal sharding all run as extensions without forking the core database. PostgreSQL's MVCC implementation provides true serializable isolation and handles complex transactions with full ACID compliance.

MySQL 9.x, now under Oracle's stewardship, remains the database that powers most of the web's read-heavy workloads. WordPress, Shopify, Facebook, and GitHub all rely on MySQL at enormous scale. MySQL's InnoDB storage engine provides excellent read performance, particularly for simple primary-key lookups and well-indexed queries. The MySQL ecosystem includes mature replication options (group replication, InnoDB Cluster), comprehensive managed offerings (Amazon RDS, PlanetScale, Vitess for sharding), and deep integration with PHP, Java, and the broader LAMP stack. MySQL's JSON support has improved significantly in recent versions, though it still lacks the indexing depth and operator richness of PostgreSQL's JSONB. MySQL's simplicity is a genuine advantage for teams that need a reliable, well-understood database without the learning curve of PostgreSQL's advanced features.

Adapter defaults to PostgreSQL for new projects because its feature breadth reduces the need for additional infrastructure. Teams that would otherwise need a separate search engine, document store, or vector database can often handle those workloads within PostgreSQL, simplifying architecture and operations. We recommend MySQL when a client's team has deep MySQL expertise, when the workload is overwhelmingly read-heavy with simple query patterns, or when the hosting environment is optimized for MySQL (such as legacy hosting providers or existing PlanetScale infrastructure). Both databases are available as managed services on every major cloud platform, so operational overhead is comparable. The choice should be driven by feature requirements and team familiarity, not myths about performance differences that have largely evaporated at the scale most applications operate.