Recall.ai faced significant performance issues with their Postgres database due to the high concurrency of NOTIFY commands used during transactions, which caused global locks and serialized commits, leading to downtime. After investigating, they discovered that the LISTEN/NOTIFY feature did not scale well under their workload of tens of thousands of simultaneous writers. They advise against using LISTEN/NOTIFY in high-write scenarios to maintain database performance and scalability.

The article discusses the evolving strategies for scaling PostgreSQL databases, emphasizing the importance of understanding Postgres internals, effective data modeling, and the appropriate use of indexing. It also covers hardware considerations, configuration tuning, partitioning, and the potential benefits of managed database services, while warning against common pitfalls like over-optimization and neglected maintenance practices.