Postgres Architecture | The Backend Engineering Show

This episode explores the architecture of PostgreSQL, focusing on the various processes it uses for maintenance and I/O operations. The host begins by introducing a diagram detailing these processes, referencing a related Medium article for further detail. He then delves into the Postmaster process, the parent process for most PostgreSQL activities, explaining its role in handling client connections and forking backend processes for each connection. More significantly, the discussion highlights the use of shared memory (shared buffers) for inter-process communication and the role of background workers in handling query execution, improving scalability compared to older versions. Against this backdrop of process-based architecture, the host details auxiliary processes like the background writer (flushing pages to disk), the checkpointer (ensuring data durability), and the auto-vacuum processes (managing database bloat). Finally, the crucial role of the wall writer and the startup process in recovery from crashes is explained, emphasizing the importance of write-ahead logging (WAL) for data consistency. This detailed examination of PostgreSQL's internal workings provides valuable insights into database design and performance optimization.