The noisy neighbor problem in multitenant SaaS architectures occurs when one tenant's heavy workload consumes disproportionate shared resources—CPU, memory, I/O, connections, or locks—degrading performance for all other tenants. The post walks through how this manifests in AWS RDS, covering mitigation strategies like resource governance, schema separation, and database-per-tenant isolation, while explaining why each approach has trade-offs. It then presents Neon's serverless Postgres architecture as a structural solution: each tenant gets a fully isolated project with its own autoscaling compute, while storage is shared efficiently. Because compute scales to zero when idle, the database-per-tenant model becomes economically viable even for low-usage tenants, eliminating both resource contention and the operational overhead of managing many RDS instances.
