Node.js 22 functions on arm64 took 570–650 ms end to end on a cold start, whether they talked to Postgres directly, through RDS Proxy, or to DynamoDB, and a function in a VPC was no slower than one outside it. Bursts of 200 simultaneous cold starts all succeeded. Warm, RDS Proxy added about 3 ms per query.
Cold start
Warm
Median time for one invocation as seen by the caller (log scale). Our measurements, November 2026. Node.js 22, arm64, 1 GB.
The VPC cold-start penalty that shaped a decade of Lambda advice is gone in these numbers. The full report breaks each cold start into initialization, connection and first query, shows what a burst of 200 does to each backend, and what RDS Proxy costs and buys.
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DynamoDB vs Postgres, Measured in AWS: 53 Workloads From the Same Client
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Ad-Hoc Questions on DynamoDB vs Postgres: 16 Analytics Queries at 100,000, 1 Million and 5 Million Orders
Every question across customers is a full table scan in DynamoDB: 217,000 read units at 5 million orders, whether it returns 10 rows or all of them. Postgres answered the same 16 questions in 0.08 to 2.7 seconds without a single index added for them, and an index built in 2.7 seconds took one from 148 ms to 44 ms. Measured in AWS.
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As of November 9, 2026. Provided as is, for general information, and accurate to the best of our knowledge on the date shown. Not legal, compliance, tax, financial or other professional advice. Prices, limits and vendor services change; check current vendor documentation before relying on anything here. Terms of use.