POSTGRES

PostgreSQL, commonly referred to as PostgreSQL, is a free and open-source relational database management system. It originated as POSTGRES, an experimental project at the University of California, Berkeley, started in 1986 under the leadership of Michael Stonebraker. The system was designed to be highly extensible, supporting user-defined data types, operators, and access methods. In the mid-1990s it adopted SQL as its query language and was renamed PostgreSQL to reflect SQL support while retaining the POSTGRES heritage.

Key features include full ACID compliance, multi-version concurrency control, reliable transactions, and a mature query planner. PostgreSQL supports a wide range of data types, indexing methods, and third-party extensions. It offers JSON and JSONB storage for semi-structured data, hstore, array types, and robust full-text search. The extension framework enables functionality such as PostGIS for geospatial data and numerous community and vendor extensions.

Architecture and operation: PostgreSQL uses a client–server model with a multi-process architecture, a shared buffer pool, write-ahead logging for durability, and a sophisticated planner and executor. It supports stored procedures in several languages (for example PL/pgSQL, PL/Python, and PL/Perl) and a broad ecosystem of tools. Replication options include streaming replication for high availability, as well as logical replication for selective data publishing; synchronous commits help meet RPO objectives.

Licensing and governance: PostgreSQL is released under the PostgreSQL License, a permissive open-source license. It is developed by a global community coordinated by the PostgreSQL Global Development Group, with ongoing releases and long-term support from various organizations.

Use cases and ecosystem: PostgreSQL is widely used in web applications, data warehousing, and analytics. It supports geospatial workloads via PostGIS, JSON-based document workloads, and complex transactions. The ecosystem includes command-line tools such as psql, graphical management interfaces, and cloud-hosted services.