PostgreSQL Architecture

**PostgreSQL Architecture** is a practitioner-focused guide that explains how the PostgreSQL engine works from the inside out. This book takes readers beyond basic administration and builds a strong mental model of PostgreSQL internals, including the process-per-connection architecture, shared and local memory, on-disk storage layout, 8 kB pages, tuple structure, MVCC, WAL, checkpoints, buffer management, asynchronous I/O, query execution, VACUUM, and autovacuum. Designed for DBAs, SREs, DBREs, DevOps engineers, and PostgreSQL learners, this book explains each concept using a clear structure: the problem it solves, the core idea, the architecture, the workflow, practical inspection commands, best practices, trade-offs, and common mistakes. It also includes diagrams and read-only diagnostic SQL commands so readers can observe PostgreSQL behavior directly on a test system. By the end of this book, readers will understand how PostgreSQL handles connections, stores rows, manages concurrency, guarantees durability, plans queries, and keeps tables healthy over time. This makes it a valuable resource for anyone who wants to troubleshoot performance issues, understand database internals, prepare for advanced DBA roles, or build a stronger foundation in PostgreSQL architecture.