tl;dr:“Our source database is about 400GB in size. It has about 1.3 billion rows, 85 tables, 185 indexes and 120 foreign keys. It is PostgreSQL version 11. On a usual weekday, we do somewhere in the region of 1,000 inserts or updates per second, plus a similar number of reads.” The DB is relied upon to send millions of important and timely notifications each day, from flood alerts to updating users about their passport applications .