feat: increase webapp Lambda memory from 512MB to 1024MB#116
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Increase the Lambda function memory size to improve cold start performance. Based on measurements across 887 requests (116 cold starts), 1024MB is the sweet spot: 3x faster cold starts (21.7s → 7.1s P50) and 32% cost reduction due to lower billed duration. Changes: - Update memorySize from 512 to 1024 in webapp.ts - Update CDK test snapshots - Update README cost table Closes #101
konokenj
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Mar 22, 2026
🤖 I have created a release *beep* *boop* --- ## [2.1.0](v2.0.0...v2.1.0) (2026-03-22) ### Features * add /update-snapshot comment trigger to update_snapshot workflow ([764a4fa](764a4fa)) * add CloudWatch LogGroup with retention policy to Lambda functions ([#117](#117)) ([53877bb](53877bb)), closes [#103](#103) * **database:** enable Data API and connection logging ([#123](#123)) ([e32dc7a](e32dc7a)) * increase webapp Lambda memory from 512MB to 1024MB ([#116](#116)) ([03c5a00](03c5a00)), closes [#101](#101) ### Bug Fixes * add lambda:InvokeFunction permission for CloudFront OAC ([#83](#83)) ([3cc66bf](3cc66bf)) * **auth:** improve auth error handling and fix Link CORS issue ([#120](#120)) ([84be605](84be605)) * disable Cognito self sign-up by default ([#115](#115)) ([9396e6f](9396e6f)), closes [#106](#106) * prevent CloudFront cache poisoning for Next.js RSC responses ([#119](#119)) ([70cddda](70cddda)) * **prisma:** add retry for Aurora Serverless v2 connection errors ([#121](#121)) ([7c05dfb](7c05dfb)) * support Amazon Linux 2023 for NAT instance ([#81](#81)) ([0c41aa8](0c41aa8)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please). Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
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Summary
Increase the webapp Lambda function memory from 512MB to 1024MB to improve cold start performance.
Problem
With 512MB (0.29 vCPU), Next.js cold starts take over 20 seconds due to CPU-bound operations (JS bundle parsing, DNS resolution, TLS handshake).
Measurement Results
1024MB is the sweet spot: 3x faster cold starts and 32% cost reduction due to lower billed duration.
Changes
cdk/lib/constructs/webapp.ts: memorySize 512 → 1024Closes #101