OpenAI scaled to a billion users on a single Postgres

OpenAI scaled to nearly a billion users using a single Postgres instance and 50 read replicas.

Read that again.

Some nuance: they delegate write-heavy workloads to Azure Cosmos DB and have stopped adding tables to the main database to ensure stability.

That said, what they pulled off with a single primary database is a massive engineering achievement.

Read the full writeup here.