What is Azure HorizonDB?
Azure HorizonDB is a new PostgreSQL wire-compatible database service from Microsoft, announced in November 2025 and in public preview since June 2026. It is built on a “database-as-logs” architecture with full separation of compute and storage: transactions commit in a single step directly to shared write-ahead log storage, reducing coordination overhead and latency. According to Microsoft, the service supports autoscaling storage up to 128 TB and scale-out compute up to 3,072 vCores across primary and replica nodes, with sub-millisecond multi-zone commit latency.
A key feature is native vector search via DiskANN, a technology developed by Microsoft Research, including advanced filtering for vector similarity search with predicate pushdown. AI models can also be invoked directly from SQL queries and transactions without external orchestration.
Core Features
- Database-as-logs architecture: Separated compute and storage layers for low latency and scalability
- PostgreSQL wire compatibility: Standard drivers and tools generally continue to work
- Native vector search: DiskANN with advanced filtering for nearest-neighbor search over large, disk-resident datasets
- In-database AI: Invoke pre-provisioned AI models directly from SQL
- Multi-zone high availability: Sub-millisecond commit latency across availability zones
Typical Use Cases
HorizonDB targets mission-critical PostgreSQL workloads that combine high performance and scalability requirements with AI capabilities such as retrieval-augmented generation (RAG). Typical scenarios include AI-powered applications with vector search directly in the operational database, and migrating existing self-managed PostgreSQL environments to a managed, highly available platform.
Benefits
- PostgreSQL compatibility lowers the migration barrier
- Separated compute/storage architecture enables independent scaling
- Native vector search removes the need for separate vector database infrastructure
- Multi-zone high availability with low latency
Frequently Asked Questions
What is Azure HorizonDB?
Azure HorizonDB is a new PostgreSQL wire-compatible database service from Microsoft, built on a “database-as-logs” architecture that fully separates compute and storage. Transactions commit directly to shared write-ahead log storage, reducing latency. The service has been in public preview since June 2026.
When should I use HorizonDB instead of Azure Database for PostgreSQL Flexible Server?
HorizonDB targets mission-critical workloads with high performance and scale requirements (Microsoft cites up to 128 TB of storage and 3,072 vCores across primary and replica nodes), as well as use cases requiring native vector search. For most standard workloads, Flexible Server remains the established, production-ready choice.
What does Azure HorizonDB cost?
Microsoft has not published final pricing at the start of the public preview. A usage-based model based on compute (vCores) and storage is expected, similar to other managed PostgreSQL offerings. Check the official documentation for current pricing before running a proof of concept.
Is HorizonDB PostgreSQL compatible?
Yes, HorizonDB is wire-compatible with PostgreSQL, so existing drivers and tools generally continue to work. Extension compatibility is still being built out during the preview phase; a current compatibility check is recommended.
Is HorizonDB production-ready?
No, HorizonDB is currently in public preview. For production workloads, Azure Database for PostgreSQL Flexible Server remains the recommended choice until HorizonDB reaches general availability with finalized SLAs.
Integration with innFactory
As a Microsoft Solutions Partner, innFactory tracks the development of Azure HorizonDB and helps you evaluate it for AI and high-performance workloads, as well as plan migrations from existing PostgreSQL databases.
Typical Use Cases
Note: All product information on this page has been compiled with care, but is provided without guarantee and may be outdated or incomplete. Cloud services evolve rapidly — features, pricing, SLAs, and availability change frequently. Authoritative and up-to-date information can only be found on the official product page of Azure (official documentation). This page does not represent an offer by Azure.
