Azure HorizonDB: Microsoft's New PostgreSQL Database

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Microsoft has unveiled the preview of Azure HorizonDB at its Ignite developer conference. The new cloud database service is based on PostgreSQL and is aimed at both developers of new applications and companies looking to modernize legacy systems. The cloud-native architecture is intended to offer scalable shared storage, flexible scale-out computing power, and a multi-tiered cache for applications of all sizes.

PostgreSQL has currently become the de facto standard for modern database projects. According to Stack Overflow, the open-source RDBMS is the most popular among professional developers. With HorizonDB, Microsoft aims to score points in an increasingly competitive market where AWS with Aurora DSQL, Google with AlloyDB, and providers like CockroachDB and YugabyteDB are already competing for market share. The new database complements Microsoft's existing portfolio of Azure Database for PostgreSQL and Cosmos DB for PostgreSQL.

The technical specifications of Azure HorizonDB promise significant performance advantages: the scale-out architecture supports up to 3072 vCores distributed across primary and replica nodes. The automatically scalable shared storage grows up to 128 TByte and, according to Microsoft, achieves sub-millisecond latency for multi-zone commits. For transactional workloads, the manufacturer promises up to three times higher throughput compared to open-source PostgreSQL. These performance gains are based, according to Microsoft's announcement, on a newly developed storage layer specifically optimized for cloud environments.

In parallel with the PostgreSQL offensive, Microsoft recently announced the general availability of SQL Server 2025, underscoring the company's dual strategy: While SQL Server 2025 also integrates AI features such as vector search and RAG support directly into the engine, HorizonDB relies on the growing PostgreSQL community and its extensive ecosystem.

AI Features and Vector Search

A focus of Azure HorizonDB is on AI applications. The service enhances PostgreSQL's vector indexing with advanced filtering capabilities in the DiskANN vector index, enabling query predicate pushdowns directly into the vector similarity search. This is intended to offer significant performance and scalability improvements over pgvector HNSW and is particularly suitable for similarity search across transactional data.

Additionally, Microsoft integrates AI model management that embeds generative models, embedding, and reranking models from Microsoft Foundry directly into the database – without manual configuration. Developers can thus leverage AI functions without needing to connect additional components. This positions HorizonDB similarly to the current Oracle AI Database 26ai as an AI-native database, but on an open-source basis.

Enterprise Requirements and GitHub Copilot Integration

For enterprise use, Azure HorizonDB offers native support for Entra ID, private endpoints, and data encryption. All data is replicated across availability zones by default, and according to Microsoft, maintenance operations occur with almost zero downtime. Backups are automatic, and integration with Azure Defender for Cloud provides additional protection for sensitive data.

Microsoft has also announced the general availability of the PostgreSQL Extension for Visual Studio Code. GitHub Copilot receives contextual information about the PostgreSQL database and can diagnose performance issues directly from the performance monitoring dashboard in agent mode. A preview function is available for migrating Oracle databases, which uses GitHub Copilot to automate the conversion of complex database codebases.

Open-Source Commitment and Availability

Furthermore, Microsoft emphasizes its commitment to the PostgreSQL project: it is one of the top corporate upstream contributors and employs 19 PostgreSQL project contributors. According to Microsoft, the team is already working on contributions for PostgreSQL 19, which is scheduled for release in 2026. Current developments, such as the performance improvements in Postgres 18 with an asynchronous IO subsystem and up to three times faster read-ahead processes, form the basis for cloud optimizations like those in HorizonDB.

Azure HorizonDB will initially be available in the Central US, West US3, UK South, and Australia East regions. Interested parties can register for early preview access at aka.ms/PreviewHorizonDB. The number of participants is limited. Microsoft has not yet announced pricing models.

(fo)