Help with "[webpack.cache.PackFileCacheStrategy] Serializing big strings (834kiB) impacts deserialization performance (consider using Buffer instead and decode when needed)"

[lancejpollard]

Summary

I keep getting this in my Next.js web app:

info Creating an optimized production build . [webpack.cache.PackFileCacheStrategy] Serializing big strings (834kiB) impacts deserialization performance (consider using Buffer instead and decode when needed)

I get this when deploying to Vercel / production, and when running next build locally. How do I debug this to figure out what is causing this statement? It is causing my builds to take over 5 minutes each time, which is annoying to work with. Is there anything straightforward to either:

1. Get rid of this problem entirely?
2. Log some stuff so I can see what is even causing this problem, so I can decide if I should change something?

Thank you for your help in advance!

Additional information

Here is my basic info:

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 22.5.0
Binaries:
  Node: 18.16.0
  pnpm: 8.8.0
Relevant Packages:
  next: 13.4.12
  eslint-config-next: 13.1.5
  react: 18.2.0
  react-dom: 18.2.0
  typescript: 4.9.4

Example

No response

[lancejpollard]

Just updated to Next.js 14 canary.1, and so far here are my production logs:

 
(node:188) ExperimentalWarning: Import assertions are not a stable feature of the JavaScript language. Avoid relying on their current behavior and syntax as those might change in a future version of Node.js.
(Use `node --trace-warnings ...` to show where the warning was created)
(node:188) ExperimentalWarning: Importing JSON modules is an experimental feature and might change at any time
   Linting and checking validity of types ...
   ▲ Next.js 14.0.2-canary.1

   Creating an optimized production build ...
 ⚠ Custom webpack configuration is detected. When using a custom webpack configuration, the Webpack build worker is disabled by default. To force enable it, set the "experimental.webpackBuildWorker" option to "true". Read more: https://nextjs.org/docs/messages/webpack-build-worker-opt-out
<w> [webpack.cache.PackFileCacheStrategy] Serializing big strings (836kiB) impacts deserialization performance (consider using Buffer instead and decode when needed)

Still taking a while. Wondering how I can better debug what it's spending time on.

[EnzoPV25]

Hi, did you find any track on how to debug this ? I also have the warning in development environment and I'd like to debbug and fix it !

[anaclumos]

Still waiting for an update

[rimzzlabs]

Im ditching nextjs now I've had enough headache just trying to make things work when building the app, thanks for 3 years 🤣

[mekhushi]

I totally get the frustration! One thing that helped me was using next-transpile-modules and tweaking Webpack configs manually. Sometimes removing unnecessary large dependencies also improves build performance. Maybe worth a shot before switching?