PostgreSQL evolved from the Ingres project at the University of California, Berkeley. In 1982, the leader of the Ingres team, Michael Stonebraker, left Berkeley to make a proprietary version of Ingres. He returned to Berkeley in

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PostgreSQL manages concurrency through multiversion concurrency control (MVCC), which gives each transaction a "snapshot" of the database, allowing

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Replication
PostgreSQL includes built-in binary replication based on shipping the changes (write-ahead logs (WAL)) to replica nodes asynchronously, with the

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Foreign data wrappers
PostgreSQL can link to other systems to retrieve data via foreign data wrappers (FDWs). These can take the form of any data source, such as a file

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PostgreSQL claims high, but not complete, conformance with the latest SQL standard (for version 13 "in September 2020, PostgreSQL conforms to at least 170 of the 179 mandatory features for SQL:2016 Core conformance", and no other databases fully

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Many informal performance studies of PostgreSQL have been done. Performance improvements aimed at improving scalability began heavily with version 8.1. Simple benchmarks

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PostgreSQL manages its internal security on a per-role basis. A role is generally regarded to be a user (a role that can log in), or a group (a role of

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