OpenAI has optimized its database infrastructure using PostgreSQL to support 800 million monthly active users and process over a million queries per second without complex sharding. The architecture consists of a single primary instance with nearly 50 read replicas, achieving low double-digit millisecond response times at the 99th percentile. OpenAI employs best practices like connection pooling, query optimization, and strategic indexing, utilizing tools such as PgBouncer for efficient connection management. The company has achieved five-nines availability through failover mechanisms and has adapted to a tenfold increase in query volume within a year by tuning PostgreSQL parameters rather than creating custom solutions. OpenAI incorporates community-driven optimizations, such as custom indexing strategies and materialized views, and uses extensions like pgvector for managing vector data and embeddings. The organization continuously monitors for strain during traffic surges and adjusts by adding replicas or optimizing configurations. Their approach emphasizes simplicity, avoiding sharding to minimize operational overhead, and they plan to explore newer PostgreSQL features and AI-native capabilities in the future.