The Internals of PostgreSQL

The Internals of PostgreSQL is a technical guide to how PostgreSQL’s major components work together. Its central aim is to make a large, complex database system understandable by explaining the mechanisms inside each subsystem and showing how they fit into the whole. The material covers database-cluster, database and table structures; process and memory architecture; query planning and execution; foreign data wrappers; concurrency control; vacuuming; heap-only tuples and index-only scans; buffer management; write-ahead logging; backup and point-in-time recovery; and streaming and logical replication. It addresses PostgreSQL 19 beta and earlier, with the new buffer-page-lock mechanism in that beta excluded.

The explanations are intended to help readers understand PostgreSQL’s operation for administration and system integration, rather than just teach SQL usage. The extensive contents and ongoing revisions include details such as parallel queries, asynchronous I/O, incremental backup, replication slots, and logical-replication workers, alongside corrections and updates for changes between PostgreSQL versions. The guide is maintained by Hironobu Suzuki, an experienced database engineer and author, and has been used in academic references and translated into Chinese. Its figures and text are freely available for educational use and noncommercial lectures with attribution; commercial reuse requires permission under the stated terms.