Why PostgreSQL Still Inspires Builders

The PostgreSQL project turned 30 years old in July.  As it enters middle-age, developers and builders rely on it more today than ever.  In the crowded and competitive SQL database market, what is driving this popularity? PostgreSQL is a great fully featured database, but it’s not clearly better than the alternatives (SQL Server, MySQL, Oracle) on performance benchmarks or in feature-by-feature comparisons. Its popularity stems from other factors: the community’s focus on reliability and stability, and its open governance and lenient licensing. Together these qualities of PostgreSQL have spawned an ecosystem of extensions and forks built around its stable core.  

A stable open core

My claim that PostgreSQL is more reliable than other databases is based on my experience and not on any hard data. I don’t know of any rigorous study on the count and severity of regressions in new releases of different database engines. Companies love to show off their TPC-C benchmark performance numbers, but we don’t have such an easily measurable metric for reliability. I’ve written code for a few different database engines in my engineering career (SQL Server, MemSQL/Singlestore in the MySQL ecosystem, and Azure HorizonDB in the PostgreSQL ecosystem). Of those, PostgreSQL is on the more conservative, careful and rigorous end of the engineering spectrum. The PostgreSQL committers may move a little more slowly when adding new features, but they move with great care.

PostgreSQL’s open and independent governance model prevents a single company from dominating its evolution. That said, large companies such as Microsoft and Amazon employ teams of engineers whose job is writing open-source PostgreSQL engine code (not working on proprietary closed source forks for their respective companies). Application developers have learned to expect a steady stream of new features year after year as a result.  PostgreSQL can run on a laptop, your own server running a variety of different operating systems, or on any of a dozen different PostgreSQL cloud services (see Table 1 below). It’s the database that gives builders the most choice and least single vendor lock-in. 

Built to extend and fork

The PostgreSQL source code is also an important building block in many PostgreSQL derived databases and services. Folks building applications in the PostgreSQL ecosystem have a broad choice of vendors and systems. PostgreSQL’s permissive license makes it the most forked open-source database engine. There are forks that specialize in data warehousing, distributed SQL and cloud native OLTP.  Its code base is a building block generating billions in revenues across the global economy for various companies. The table below shows some of the PostgreSQL compatible databases or services in production today. They include more specialized forks built to handle use cases that community Postgres is not as good at (i.e., data warehousing) as well as services that run mostly unmodified Postgres as a cloud service. The databases in bold are available on Azure.

Table 1 – Postgres based databases or services; Not an exhaustive list. For more see PostgreSQL derived databases - PostgreSQL wiki

No other open-source database has as many successful product offerings based on its source code or its query and wire protocols. MySQL would be a distant second place as far as number of derived databases or services. The databases listed above aren’t all fully compatible with community PostgreSQL, but many are highly compatible.  

Postgres on Azure

At Azure, we’ve built three services around PostgreSQL shown in bold in Table 1  

1. Azure Database for PostgreSQL runs Postgres on Azure virtual machines and Azure managed disks managing backups, high availability, and geo-replica’s as needed. It offers the Citus extension (via the Elastic Clusters configuration) to shard data across a cluster of Postgres worker machines to scale out writes and reads as needed.
2. Azure HorizonDB extends the core PostgreSQL engine with a custom storage layer that has specialized WAL and page services improving performance, reliability and scalability. It frees up Postgres to run queries and transactions by pushing the work to make data durable and highly available into the storage layer (replication, checkpointing, WAL archival, etc.).
3. Azure DocumentDB gives customers the option to build apps against a MongoDB compatible service on top of PostgreSQL’s solid foundation.  

So, thank you to the PostgreSQL developers (and community) for the hard work they’ve put in over three decades. The family of Postgres derivative or compatible databases wouldn’t exist with their foundational work. Choosing Postgres gives builders the confidence they’re building on a mature, reliable and flexible foundation. Who knows where a new fork or extension may take Postgres in the future.

About PostgreSQL Perspectives

PostgreSQL Perspectives is a monthly blog series featuring insights from Microsoft engineers, contributors, and builders working with PostgreSQL. Explore more articles on the Microsoft for PostgreSQL blog.