mongodb-connection

Prevent MongoDB connection pool exhaustion in serverless functions by initializing a single MongoClient outside the handler for warm reuse, setting a conservative maxPoolSize like 5, and configuring maxIdleTimeMS to 20000 to manage connection lifecycle efficiently.

A high-traffic API throws a MongoWaitQueueTimeoutError when connection demand exceeds the configured maxPoolSize. Resolve this by tuning maxPoolSize and minPoolSize, applying conservative timeouts, and monitoring driver pool events to ensure capacity satisfies peak concurrency constraints.

The best way to configure MongoDB timeouts for OLTP workloads is to apply conservative timeout settings alongside appropriate connection pooling limits. This prevents excessive connection churn and ensures sustained performance for long-running servers handling rapid, high-volume transactions.

Monitor MongoDB connection churn by instrumenting driver pool events to track ConnectionCheckOutFailed and rapid ConnectionCreated events. Interpret server-level connection metrics like connections.current and wait queue lengths to identify and resolve pool exhaustion issues proactively.

MongoDB client reuse works effectively with AWS Lambda warm invocations by declaring a single MongoClient instance globally outside the handler. This avoids connection churn and allows subsequent invocations to share the existing connection pool securely.

When MongoDB connections fail with ECONNREFUSED during high bursts, troubleshoot by validating your serverless connection configuration. Ensure single-client reuse is active, verify maxPoolSize limits are not overly restrictive, and check driver pool events for sudden connection drops.