Episode 44 Season Finale: The Life of a Query, Revisited

The finale of Season 1. Episode 1's map of Postgres again, with every box opened up: parser, planner, executor, indexes, buffer pool, transactions and the WAL. Then one UPDATE followed all the way down on real Postgres: its plan, its WAL bytes, its transaction id and locks, the new row version, COMMIT waiting for the flush, and the dirty page a checkpoint writes later.