Difference Between Postgresql And Mysql

Dingyi Lai / March 2025

PostgreSQL and MySQL are both very popular open-source relational database management systems (RDBMS), but they have some key differences in their design philosophies, features, and typical use cases. In one of my previous working experience, we used MySQL. But after some research, I found that there are the main distinctions between the two:

1. System Type and Design Philosophy:
   • PostgreSQL: Is an Object-Relational Database Management System (ORDBMS). This means it supports standard relational features plus more complex data types (like arrays, JSON/JSONB, custom types), inheritance, and other object-oriented concepts. Its design philosophy emphasizes feature richness, strict adherence to SQL standards, data integrity, and extensibility.
   • MySQL: Is a purely Relational Database Management System (RDBMS). Its design philosophy originally focused more on speed, ease of use, and simplicity of deployment. While MySQL has been adding features over the years, its core remains that of a traditional RDBMS.
2. SQL Standard Compliance:
   • PostgreSQL: Is known for its strict adherence to the SQL standard, supporting many advanced features defined in the standard.
   • MySQL: Historically, its implementation of the SQL standard might have been less strict in some areas, or it had its own extensions (though recent versions have improved significantly). It sometimes prioritized performance or simplicity over strict standard compliance.
3. Data Types and Feature Richness:
   • PostgreSQL: Supports a very rich set of data types, including arrays, range types, geometric types (via the PostGIS extension), powerful JSON/JSONB support, enumerated types, network address types, UUIDs, and more. It also has strong built-in support for advanced features like window functions, Common Table Expressions (CTEs), materialized views, and full-text search.
   • MySQL: Supports standard SQL data types and has enhanced its JSON support in recent years. However, its built-in data types and advanced analytical features (e.g., window function support might be less mature or arrived later than in PostgreSQL) are generally not as extensive or natively integrated as PostgreSQL’s.
4. Concurrency Control (MVCC):
   • Both use Multi-Version Concurrency Control (MVCC) to handle simultaneous reads and writes, reducing lock contention. However, the specific implementation details and performance characteristics can differ. PostgreSQL’s MVCC implementation is often considered very mature and robust, especially for handling long-running transactions and high concurrent write loads.
5. Extensibility:
   • PostgreSQL: Has a very powerful extension framework. Users can easily add various extensions (like PostGIS for geospatial data, TimescaleDB for time-series data) and even write custom functions, data types, and operators in languages like C, Python, etc. This makes PostgreSQL highly flexible and adaptable to specific needs.
   • MySQL: Primarily achieves extensibility through its Storage Engine architecture (InnoDB and MyISAM being the most common, though MyISAM is less recommended now). While it also supports User-Defined Functions (UDFs), its overall extension framework is generally less flexible and powerful than PostgreSQL’s.
6. Replication:
   • PostgreSQL: Primarily offers Streaming Replication (physical or logical), which is typically asynchronous but can be configured as synchronous. Logical replication provides more fine-grained control.
   • MySQL: Offers various replication methods, including Statement-Based Replication (SBR), Row-Based Replication (RBR), and Mixed-Based Replication (MBR). It’s typically asynchronous but can be configured for semi-synchronous or fully synchronous replication (via plugins).
7. Performance:
   • This is complex and depends heavily on the specific workload, configuration, and hardware. No database is universally faster.
   • General Perception: MySQL might exhibit higher speeds for read-heavy, simpler query workloads (especially in older versions or specific configurations).
   • General Perception: PostgreSQL often performs more robustly and consistently with complex queries, write-heavy workloads, high concurrency, and when advanced data types/features are needed.
8. Transaction Support (ACID):
   • PostgreSQL: Has always been fully ACID compliant.
   • MySQL: ACID compliance depends on the storage engine used. The most common engine, InnoDB, is fully ACID compliant. However, older or non-transactional engines like MyISAM do not guarantee ACID properties.

Summary Table:

How to Choose?

• Choose PostgreSQL if the application requires:
  • Handling complex data types (geospatial, JSON, arrays).
  • Strict SQL standard compliance.
  • Extensive use of advanced query features (window functions, CTEs).
  • High extensibility via extensions.
  • Robust performance under complex loads or high write concurrency.
• Choose MySQL if the application:
  • Is primarily read-heavy with simpler queries.
  • Requires extremely high raw speed for simple operations.
  • Prioritizes ease of deployment and has less need for advanced features.
  • The team has deep existing expertise in MySQL (using the InnoDB engine for ACID compliance is strongly recommended).

In recent years, the feature gap has narrowed, with MySQL adding more capabilities and PostgreSQL continually improving performance. The best choice often depends on specific business needs, team experience, and performance benchmarking for the particular workload.