Reading the internals of Postgres: Database cluster, databases, and tables

This article explains PostgreSQL's internal architecture, revealing how databases are logically organized through object identifiers (OIDs) and physically stored in the file system under $PGDATA directories—critical knowledge for IT leaders managing database infrastructure and performance optimization. Understanding these internals enables CIOs to better evaluate PostgreSQL deployment strategies, troubleshoot storage issues, and make informed decisions about database scaling and maintenance. For organizations relying on PostgreSQL, this foundational knowledge becomes essential as database sizes grow and operational complexity increases.