How RDS Proxy Prevents Lambda Functions from Overwhelming Your Database

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Serverless AWS architectures using Lambda and RDS can fail under high traffic because each Lambda invocation opens a new database connection, quickly exceeding RDS instance limits. A db.t3.micro supports roughly 66 connections, meaning even moderate concurrency can trigger 'Too many connections' errors and bring down an API. Amazon RDS Proxy addresses this by acting as a managed intermediary that maintains a reusable pool of persistent connections, so thousands of Lambda invocations share a small set of database connections instead of creating new ones. Beyond connection pooling, RDS Proxy also offers faster failover, IAM-based authentication, and improved security. Developers can further reduce connection churn by initializing database connections outside the Lambda handler, allowing warm execution environments to reuse existing connections.

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