Postgres vs. SQL Server: a Complete Comparison in 2025

Originally posted in https://www.bytebase.com/blog/postgres-vs-sqlserver/

Hi and welcome to Database DevOps Academy #85! We share Database DevOps insights and best practices for modern engineering organizations weekly. 🚩

In Issue #85, we made a thorough comparison between PostgreSQL and SQL Server which represent two different philosophies in database management systems. ☎️

This post is maintained by Bytebase, an open-source database DevSecOps tool that can manage both Postgres and SQL Server. We update the post every year.

Why Comparing PostgreSQL and SQL Server

When comparing PostgreSQL and SQL Server, we're examining two enterprise-class database systems with different business models but similar capabilities. SQL Server represents the commercial approach with licensing costs and Microsoft ecosystem integration, while PostgreSQL offers comparable enterprise features (high availability, security, advanced SQL capabilities) as an open-source solution without licensing fees.

This similarity in target applications, combined with PostgreSQL's feature parity and growing enterprise support ecosystem, makes it the natural first choice when organizations consider migrating away from SQL Server—offering a path to reduce licensing costs while maintaining enterprise-grade database capabilities.

This comparison reflects the current state of both systems as of 2025, including the latest versions: PostgreSQL 17.4 (with PostgreSQL 18 on the horizon) and SQL Server 2025 (currently in preview):

• Feature Comparison
• Technical Specifications
• Development Workflow
• Pricing and Licensing
• Future Outlook
• Conclusion

Feature Comparison

Core Database Features

Advanced Features

PostgreSQL-Specific Features

1. Extensibility: PostgreSQL's architecture allows for custom data types, operators, and functions through its extension system.
2. Foreign Data Wrappers: Allows PostgreSQL to connect to other data sources and treat them as local tables.
3. Multi-Version Concurrency Control (MVCC): Provides efficient concurrent access without read locks.
4. Point-in-Time Recovery: Allows restoration to any point in time using write-ahead logs.
5. Full-Text Search: Built-in capabilities for text search with language support.
6. Geospatial Support: PostGIS extension provides robust geospatial capabilities.
7. JSON/JSONB Support: Native JSON types with indexing and querying capabilities.
8. Table Inheritance: Supports table inheritance for object-relational designs.

SQL Server-Specific Features

1. In-Memory OLTP: Memory-optimized tables and natively compiled stored procedures.
2. Columnstore Indexes: Highly compressed storage format optimized for analytical queries.
3. Intelligent Query Processing: Adaptive joins, memory grant feedback, and approximate count distinct.
4. Temporal Tables: Built-in support for tracking historical data changes.
5. PolyBase: Technology for querying external data sources.
6. Stretch Database: Dynamically extends warm and cold data to Azure.
7. Graph Database Capabilities: Node and edge table types for graph data modeling.
8. Microsoft Fabric Integration: Seamless integration with Microsoft's analytics platform.

Technical Specifications

Architecture

PostgreSQL Architecture:

• Process-based architecture where each client connection spawns a new server process
• Shared memory used for caching and inter-process communication
• Write-Ahead Logging (WAL) for durability and crash recovery
• Multi-Version Concurrency Control (MVCC) for transaction isolation
• Extensible design with hooks for custom functionality
• Catalog-driven operations and metadata management

SQL Server Architecture:

• Thread-based architecture with a thread pool for handling client connections
• SQLOS layer providing thread scheduling, memory management, and I/O services
• Buffer pool for caching data pages in memory
• Transaction log for durability and recovery
• Lock manager for concurrency control
• Query processor with cost-based optimizer
• Storage engine with support for multiple storage formats

Index Capabilities

Basic Index Types

Index Features and Options

Special Index Types

Development Workflow

SQL Server offers a more integrated development experience through DACPAC and SQL Database Projects, providing standardized tools for enterprise environments with strong governance requirements.

PostgreSQL offers a flexible approach using community and third-party tools, allowing for customized workflows but requiring more manual integration.

Bytebase streamlines database development workflows for both SQL Server and PostgreSQL, with specialized advantages for PostgreSQL users. It introduces project-based collaboration and Git-like schema version control to PostgreSQL environments, enabling teams to manage database changes with automated migration scripts, change reviews, and granular access controls.

Pricing and Licensing

PostgreSQL Licensing Model

PostgreSQL is released under the PostgreSQL License, a liberal open-source license similar to the BSD or MIT licenses.

SQL Server Licensing Models and Pricing

Based on the latest SQL Server 2022 pricing

1. Core-Based Licensing

Key Considerations for Core-Based Licensing:

• Minimum requirement of 4 cores per physical processor
• All cores in the physical processor must be licensed
• Enterprise Edition includes unlimited virtualization rights
• Software Assurance required for License Mobility

2. Server + CAL Licensing

• Server license: $989 per server instance
• Client Access Licenses (CALs): $230 per user or device

3. Modern Cloud-Based Pricing

Azure Arc-Enabled Pay-As-You-Go:

Subscription-Based Pricing:

Future Outlook

PostgreSQL 18 (Expected September 2025):

• Query optimizer improvements including Hash Right Semi Join implementation
• 40% reduction in memory usage for joins with large datasets
• 15% faster execution times for EXISTS subqueries
• Enhanced logical replication capabilities
• Improved parallel query execution
• Better integration with cloud environments

SQL Server 2025 (Currently in Preview):

• Deep AI integration with built-in vector database capabilities
• Enhanced security features including Microsoft Entra managed identities
• Performance improvements including optimized locking
• Intelligent Query Processing enhancements
• Stronger cloud integration with Microsoft Fabric and Azure Arc

Conclusion

PostgreSQL and SQL Server represent two different philosophies in database management systems: the open-source, community-driven approach versus the commercial, integrated ecosystem approach. Both systems have evolved significantly and offer robust, enterprise-grade features in 2025.

PostgreSQL Advantages:

• Zero licensing costs with a permissive open-source license
• Extensive data type support and extensibility
• Growing popularity and community support
• Freedom from vendor lock-in

SQL Server Advantages:

• Deep integration with Microsoft's ecosystem
• Advanced business intelligence and analytics capabilities
• Comprehensive enterprise features out-of-the-box

As both systems continue to evolve, they are likely to address their respective weaknesses while building on their strengths. PostgreSQL is gaining more enterprise features and commercial support options, while SQL Server is becoming more open and flexible with Linux support and containerization.

References

1. PostgreSQL Official Documentation
2. Microsoft SQL Server Documentation
3. Stack Overflow Developer Survey 2024
4. Microsoft SQL Server 2025 Preview Announcement (November 2024)