Discover how you should go about choosing between the three popular open source relational database management systems – PostgreSQL, MySQL and MariaDB.

In the ever-evolving world of software development, data lies at the heart of every application. Whether you’re building a high-traffic e-commerce platform, a lightweight web app, or an enterprise-level analytics engine, your choice of database can make or break your project. Among the multitude of options, three names dominate the open source relational database landscape: PostgreSQL, MySQL, and MariaDB. Each of these RDBMS (relational database management systems) has carved out a loyal user base and distinct identity, offering a mix of speed, reliability, extensibility, and community support.

The story of open source databases begins with the need for freedom — freedom from vendor lock-in, freedom to customise, and freedom to innovate. While commercial databases like Oracle and SQL Server once ruled the enterprise world, developers around the globe began to shift towards more flexible and cost-effective alternatives.

MySQL, created in 1995, quickly became a favourite due to its simplicity, performance, and ease of integration with the LAMP stack. PostgreSQL, although older (dating back to the 1980s as the ‘POSTGRES’ project), steadily gained traction for its advanced features and standards compliance.

Enter MariaDB — born out of concern when Oracle acquired Sun Microsystems (and with it, MySQL) in 2010. Michael ‘Monty’ Widenius, one of MySQL’s original creators, forked the project to ensure that the community retained full control and transparency.

This sparked a new era of competition and innovation in the open source database world, giving rise to three strong contenders — each with its own philosophy, community, and technical direction.

• PostgreSQL is often dubbed the “world’s most advanced open source database.” Known for its powerful support for complex queries, full ACID compliance, and standards-based architecture, PostgreSQL is the go-to choice for applications where data integrity and extensibility are paramount
• MySQL, now owned by Oracle, remains one of the most widely adopted databases globally. It is synonymous with speed, simplicity, and ease of use. Many popular platforms, including WordPress and Drupal, rely on MySQL under the hood.
• MariaDB positions itself as a drop-in replacement for MySQL but has evolved into a distinct database with its own performance enhancements, storage engines, and security features. Driven by a passionate open source community, MariaDB offers both compatibility and innovation.

Despite their shared roots in relational database principles, these three systems differ significantly in design philosophy, feature sets, licensing, and use cases — making the choice between them far from trivial.

The contenders: A quick profile

MySQL: The web application workhorse

If you’ve ever built or run a website, chances are you’ve interacted with MySQL — either directly or through a content management system like WordPress, Joomla, or Drupal. MySQL earned its place in the spotlight by offering a fast, reliable, and easy-to-use solution for web applications. It became a cornerstone of the famous LAMP stack (Linux, Apache, MySQL, PHP), making it a default choice for countless developers and hosting providers.

MySQL’s strengths lie in its speed, simplicity, and mature ecosystem. It handles read-heavy workloads like blog posts, product catalogues, and dashboards with ease. Over the years, Oracle’s stewardship has added enterprise features, improved security, and maintained compatibility — but it’s also led some developers to question its open source commitment. Nevertheless, with massive global adoption and a robust support infrastructure, MySQL remains a go-to database for small to medium-sized web applications that prioritise speed and ease of deployment.

MariaDB: The community-driven alternative

Born from the same DNA as MySQL, MariaDB is more than just a clone — it’s a community-led evolution. Created by the original developers of MySQL in response to Oracle’s acquisition, MariaDB promised to stay truly open, transparent, and innovative. And it was delivered. While maintaining drop-in compatibility with MySQL (especially in earlier versions), MariaDB has introduced its own set of optimisations, unique features, and performance-focused storage engines like Aria and ColumnStore.

MariaDB is known for its commitment to open source, its frequent release cycle, and its cutting-edge improvements in speed, scalability, and replication. Many Linux distributions, including Fedora and Arch, have even replaced MySQL with MariaDB as their default RDBMS. For developers and organisations who value openness and community-driven development — without sacrificing performance — MariaDB is an attractive and forward-thinking choice.

PostgreSQL: The feature-rich powerhouse

If MySQL and MariaDB are built for speed and simplicity, PostgreSQL is designed for power, precision, and possibility. Often referred to as the most advanced open source relational database in the world, PostgreSQL (or ‘Postgres’) is a favourite among developers who demand full SQL compliance, support for complex queries, and extensibility.

PostgreSQL shines in scenarios that require data integrity, custom data types, advanced indexing, geospatial support (PostGIS), and horizontal scaling options. It’s a top choice for financial systems, scientific research, analytics platforms, and enterprise-grade applications that need to handle large volumes of data with accuracy and control. With a strong academic foundation and decades of active development, PostgreSQL offers not just features, but future-proofing — thanks to its modular architecture and thriving plugin ecosystem.

Head-to-head comparison: Key technical aspects

Architecture and design philosophy:

MySQL and MariaDB use a pluggable storage engine model, so different engines can be used for different needs. Their default engine, InnoDB, supports transactions and full ACID compliance, but developers can switch to engines like MyISAM (optimised for read-heavy legacy workloads) or Aria (a MariaDB-specific engine designed for crash recovery). In contrast, PostgreSQL uses a unified monolithic architecture that is less modular but highly extensible, allowing the creation of custom data types, operators, indexing methods, and procedural functions. This approach favours predictable performance and strict SQL standard compliance, making PostgreSQL a preferred choice for enterprise-grade systems where consistency is key.

Performance and concurrency

MySQL and MariaDB are generally faster for simple read/write operations, especially in web applications with low-complexity transactions, due to lightweight configurations and aggressive caching. However, when dealing with complex queries involving multiple joins, aggregations, and recursion, PostgreSQL outperforms thanks to its sophisticated query planner, support for Common Table Expressions (CTEs), window functions, and advanced indexing methods like GIN and BRIN. For concurrency, PostgreSQL leverages Multiversion Concurrency Control (MVCC) more effectively, enabling multiple readers and writers to interact without blocking each other. MySQL/MariaDB also use MVCC via InnoDB but tend to fall back to traditional locking in edge cases, which can impact performance in high-concurrency environments.

Data integrity and ACID compliance

All three databases provide full ACID compliance when transactional engines like InnoDB (for MySQL/MariaDB) or PostgreSQL’s native system are used. However, PostgreSQL stands out with its rigorous implementation of isolation levels (including Serializable and Repeatable Read) and support for nested transactions through SAVEPOINT, allowing for more controlled rollbacks and finer transaction management. MySQL and MariaDB, while compliant, require careful engine selection, as switching to non-transactional engines like MyISAM compromises ACID guarantees.

Data types and JSON support

PostgreSQL excels in data type richness. Beyond standard SQL types like INTEGER, FLOAT, VARCHAR, it supports native arrays, UUIDs, geometric types, IP addresses, and even user-defined types, making it ideal for complex data models. Its JSON support is industry-leading, offering both JSON and JSONB (binary JSON), which allows indexing, deep querying, and seamless integration with SQL queries. In contrast, MySQL and MariaDB offer JSON data types and functions, but their JSON features are less powerful, often lacking advanced querying and indexing support, making PostgreSQL the top choice for semi-structured data.

Replication and scalability

Replication is vital for high availability and distributed systems. MySQL supports asynchronous and semi-synchronous replication, making it suitable for simple master-slave setups. MariaDB enhances this with multi-source replication (replicating from multiple masters) and Galera Cluster for true synchronous replication and high availability. PostgreSQL supports both physical (streaming) and logical replication, as well as bidirectional replication (BDR) via community-supported extensions, allowing more flexible replication strategies. For scalability, all three support vertical scaling (adding CPU/RAM), but for horizontal scaling, PostgreSQL uses extensions like Citus for distributed workloads, whereas MariaDB offers the Spider storage engine to support sharding, giving developers multiple options based on architecture needs.

Extensibility and features

PostgreSQL is widely recognised for its deep extensibility. It allows custom extensions like PostGIS (for geospatial data), pg_partman (for partition management), and pluggable procedural languages (like PL/pgSQL, Python, Perl, etc). It supports event triggers, custom background workers, and a wide range of performance tuning tools. MariaDB brings its own innovation, such as dynamic columns (to store varied schema data within a single table), virtual/generated columns, and ColumnStore for analytical (OLAP) queries. MySQL, while more conservative in features, remains reliable and widely supported, especially in traditional LAMP stack environments. All three support stored procedures, triggers, views, and event schedulers, but PostgreSQL provides greater depth and control.

Licensing

Licensing can impact long-term project decisions. PostgreSQL uses a permissive licence (PostgreSQL License) similar to MIT or BSD, allowing full freedom in commercial and academic use with minimal restrictions. MySQL, on the other hand, uses GPL v2 with a commercial licence from Oracle, which can be problematic for companies that want to embed MySQL without open sourcing their application. MariaDB, also GPL v2 licensed, is governed by the MariaDB Foundation, offering more transparency and community trust than Oracle’s stewardship of MySQL. This distinction makes PostgreSQL and MariaDB more attractive for open source and enterprise projects that prioritise licensing freedom.

Usability and ecosystem

Ease of use and learning curve

When it comes to ease of use and learning curve, MySQL and MariaDB have a clear edge in terms of installation and setup, offering quick and straightforward processes with packages readily available for most operating systems and cloud platforms—a convenience stemming from their shared lineage.

PostgreSQL, while slightly more complex to configure, compensates with production-ready defaults that cater to enterprise-grade deployments. In terms of management tools, MySQL and MariaDB provide excellent support for beginners through user-friendly GUIs like phpMyAdmin and MySQL Workbench, which simplify administration tasks and data handling. PostgreSQL, on the other hand, relies on pgAdmin—a powerful yet occasionally slower tool that includes a query editor, server monitoring, and administrative features.

All three databases are backed by solid documentation and active communities. PostgreSQL is especially noted for its thorough, academically rigorous documentation that appeals to advanced users, while MySQL and MariaDB provide accessible manuals and guides, with MariaDB emphasising transparency and community-driven development. Across the board, tutorials, forums, and discussions on platforms like Stack Overflow are plentiful, though MySQL generally leads in beginner-friendly content due to its long-standing dominance in web development environments.

Community and market adoption

In terms of community and market adoption, MySQL remains one of the most widely used databases globally, especially favoured in web applications and content management systems like WordPress, as confirmed by the Stack Overflow Developer Survey (2024).

PostgreSQL, however, has experienced a significant rise in popularity due to its rich feature set and growing support among enterprise-grade applications and modern development frameworks.

Although MariaDB holds a smaller market share, it is highly respected in open source circles and is frequently chosen by developers looking for a MySQL-compatible alternative with more favourable licensing. The developer communities surrounding each of these databases are active and influential—PostgreSQL boasts a technically sophisticated contributor base led by the PostgreSQL Global Development Group and supported by companies like EDB, while MySQL benefits from Oracle’s strong backing and a massive user base in LAMP stack deployments. MariaDB thrives under the stewardship of the MariaDB Foundation, appealing especially to users who prefer transparency and independence from corporate control. In terms of platform adoption, PostgreSQL is now a default choice in many cloud services such as AWS RDS, Google Cloud SQL, and Heroku, reflecting its growing enterprise appeal. MySQL, meanwhile, enjoys broad exposure thanks to its inclusion in most shared hosting services. MariaDB is the default database in several Linux distributions, including Fedora and openSUSE, further cementing its place in the open source ecosystem.

Compatibility and migration

MariaDB was originally developed as a drop-in replacement for MySQL, allowing most applications and tools built for MySQL to run on it without any modifications. This seamless compatibility is made possible by their shared file formats and client protocols, which significantly reduce migration overhead. However, as both systems have evolved independently, differences in storage engines, optimizers, and feature sets may introduce challenges in more complex environments.

On the other hand, migrating between MySQL/MariaDB and PostgreSQL is considerably more involved due to fundamental differences in SQL dialects—such as how they handle JSON data, window functions, and specific data types—as well as in indexing mechanisms, constraints, and procedural language support. Fortunately, tools like pgLoader, AWS Schema Conversion Tool, and Ora2Pg offer valuable support for schema translation and data migration. Though such migrations are not trivial, they are increasingly pursued by organisations seeking greater ACID compliance, richer SQL capabilities, or enhanced scalability provided by PostgreSQL.

Use case scenarios: What to choose when

The choice between PostgreSQL, MySQL, and MariaDB often hinges on the specific requirements and context of a project.

For web applications, especially content-driven platforms like blogs, forums, content management systems (CMS) such as WordPress, or lightweight e-commerce stores, MySQL and MariaDB stand out for their simplicity, speed, and widespread support across hosting environments. Their ease of setup, broad compatibility with PHP-based stacks, and large pool of community resources make them ideal for small to medium-sized applications with read-heavy workloads.

In contrast, PostgreSQL is the preferred choice for enterprise-grade applications where robustness, data integrity, and complex transactional operations are paramount. Industries such as finance, healthcare, logistics, and public sector services often adopt PostgreSQL due to its strong ACID compliance, support for advanced data types, and features like table inheritance, JSONB, and role-based security.

When it comes to data warehousing and business intelligence (BI), PostgreSQL once again leads with its superior support for analytical queries, indexing strategies, materialised views, and extensions like cstore_fdw and PostGIS, making it highly efficient for OLAP workloads.

MariaDB also enters this space with support for columnar storage engines, catering to BI use cases where fast, aggregated reporting is needed. Finally, in the context of legacy systems and migration, organisations must weigh factors such as schema compatibility, cost of downtime, licensing restrictions, and long-term maintainability. Migrating from MySQL to MariaDB is often seamless due to their binary and protocol compatibility, whereas moving to PostgreSQL requires thoughtful planning due to differences in SQL dialects, indexing strategies, and data type support.

Tools like pgLoader, AWS SCT, or Ora2Pg can aid in the transition, but organisations must also decide whether to perform a ‘lift-and-shift’ migration (preserving existing structures) or to refactor the application to fully leverage PostgreSQL’s advanced capabilities. Choosing the right RDBMS ultimately depends not only on technical fit but also on the project’s future scalability, team expertise, and ecosystem alignment.

A final recommendation

As we conclude this comprehensive comparison of PostgreSQL, MySQL, and MariaDB, it becomes clear that each brings its own strengths and trade-offs depending on the context of use. For developers seeking simplicity, quick deployment, and a wide range of third-party integrations, MySQL continues to be a reliable choice, especially for content management systems, blogs, and e-commerce platforms where read-heavy workloads dominate. MariaDB, while closely related to MySQL, stands apart for its strong commitment to open source principles, more transparent development model, and inclusion of performance-focused features like alternative storage engines and improved optimizer strategies. It is especially attractive to those seeking a MySQL-compatible system without proprietary constraints. On the other hand, PostgreSQL shines when robustness, data integrity, and advanced features are paramount. With its powerful support for complex queries, extensibility through modules like PostGIS, full ACID compliance, and advanced data types such as JSONB, arrays, and custom types, PostgreSQL is ideal for enterprise applications, financial systems, and analytical workloads that demand high reliability and performance.

To assist with decision-making, a high-level summary can be helpful: MySQL and MariaDB are often preferred for simpler web applications with low administrative overhead, while PostgreSQL is best suited for mission-critical systems requiring sophisticated data handling. MySQL offers ease of use and massive adoption in web hosting environments, MariaDB is favoured in open-source-first infrastructures, and PostgreSQL is growing rapidly in cloud-native, data-intensive ecosystems. While each system offers replication, indexing, and JSON capabilities, PostgreSQL’s implementations tend to be more feature-complete and scalable. The choice should ultimately align with your application’s architecture, your team’s technical expertise, and long-term project goals.

Looking to the future, all three databases are positioned to remain vital in the open source landscape. PostgreSQL continues to gain momentum in cloud services and modern development stacks, with growing support from managed platforms and active community-driven innovation. MariaDB is evolving with enterprise-grade features and hybrid transactional/analytical capabilities, while maintaining its grassroots, community-oriented ethos. MySQL, under Oracle’s direction, still benefits from strong corporate backing and innovations like HeatWave, targeted at cloud-native analytics. As data continues to power modern applications, the question is not which database is ‘best’ universally—but which is best for you. Choosing the right open source RDBMS means aligning database capabilities with your current project needs, scalability goals, licensing preferences, and the evolving demands of the tech landscape.