Semab Tariq continues a series on internals in PostgreSQL:
PostgreSQL is a client/server type relational database management system. It has a multi-process architecture that runs on a single host. A collection of multiple processes that manage a database cluster is usually referred to as a PostgreSQL server. In PostgreSQL, every operation is treated as a process, and each action we undertake within PostgreSQL follows an append-only approach. This means that every time we execute an action such as an insert, update, or delete, a new tuple is created rather than modifying the existing data directly.
Consequently, PostgreSQL does not execute updates or deletes in place. Instead, it appends new data or marks existing data as obsolete. This append-only methodology ensures data integrity and allows for efficient management of database changes over time.
Read on to learn more about how these processes work.