In a strategic move that signals a shift in the database landscape, Microsoft has introduced open source extensions for PostgreSQL aimed at handling document-style data. This initiative not only challenges MongoDB’s dominance in the NoSQL market but also highlights the diminishing divide between relational and non-relational database systems.
Late last month, Microsoft unveiled two key extensions to PostgreSQL: pg_documentdb_core and pg_documentdb_api. The former enables support for Binary JavaScript Object Notation (BSON), a binary-encoded serialization of JSON documents, while the latter provides a MongoDB-compatible API for create, read, update, and delete (CRUD) operations, queries, and index management. These extensions will run on the Azure Cosmos DB PostgreSQL database service.
A Growing Trend: Converging Relational and NoSQL Technologies
Andrew Pavlo, Associate Professor of Databaseology at Carnegie Mellon University, noted that the PostgreSQL extensions are part of a broader trend where NoSQL databases are gradually adopting relational database features.
“The intellectual distance between document/JSON DBMSes and relational DBMSes is shrinking,” Pavlo said. “At some point, the two system categories will be indistinguishable in terms of the data model. The DocumentDB/FerretDB announcement is further evidence of this.”
Microsoft has also indicated that its extensions can be integrated with FerretDB, an open source MongoDB alternative. FerretDB’s CEO, Peter Farkas, emphasized the importance of collaboration in building a strong alternative to MongoDB.
“The goal is to work broadly among MongoDB alternatives and foster cooperation. Over time, a unified foundation for MongoDB alternatives will emerge, benefiting users who seek open source solutions,” Farkas stated.
MongoDB Pushes Back
MongoDB, which pioneered the document database market in the early 2010s, remains skeptical about Microsoft’s approach.
A spokesperson from MongoDB criticized Microsoft’s attempt to compete, stating:
“The rise of MongoDB imitators proves our document model is the industry standard. But bolting an API onto a relational database isn’t innovation—it’s just delaying the inevitable second migration when performance, scale, and flexibility hit a wall. Developers building AI-powered applications don’t have time for do-overs. MongoDB is purpose-built to get it right the first time.”
The Future of PostgreSQL in Document Databases
PostgreSQL has supported JSON documents since 2013, gradually enhancing its capabilities over the years. However, Farkas pointed out that PostgreSQL’s core JSON support alone is insufficient to compete directly with MongoDB. Extensions, he argued, offer a practical way to enhance functionality without modifying PostgreSQL’s core architecture.
Industry analysts remain divided on Microsoft’s broader open source strategy. Aaron Rosenbaum, Senior Director Analyst at Gartner, remarked that while Microsoft has been a significant contributor to PostgreSQL, this does not indicate a wider embrace of open source database management systems (DBMSes).
“We see this as a continuation of their PostgreSQL work,” Rosenbaum said. “Microsoft is deeply committed to SQL Server, but they are also serious about supporting PostgreSQL. This is similar to their approach to Linux and Windows Server on Azure.”
Henry Cook, another Gartner analyst, added that Microsoft’s PostgreSQL enhancements further strengthen its position in the database market and as an interface for DBMS services.
Conclusion
Microsoft’s foray into open source document databases represents both an expansion of PostgreSQL’s capabilities and a direct challenge to MongoDB. As the database landscape evolves, the distinction between relational and NoSQL technologies is becoming increasingly blurred, setting the stage for intensified competition and innovation in database management systems.