After upgrading angular 11 to 12, CPU utilization goes 100%

Bug Report

Affected Package

This issue is caused by package @angular/core and @angular/cli but not sure yet.

Is this a regression?

With Angular 11, everything is fine, but after upgrading to 12, cup goes 100%.

Description

Our project is not that big, maybe small. And we were using Angular 11 with Angular Material and also Angular universal for SSR. Today, I read about Angular 12 release so updated project version to 12. After that server went down every 10 minutes and we made some investigation and found that pm2 instance occupying CPU utilization 102%.

As a temporary solution, I downgraded it again to 11 and all became fine.

Minimal Reproduction

Not sure how can I reproduce error, just reporting this issue to Angular team. But I am attaching screenshot.

Exception or Error

Please check the screenshots.

Your Environment

Angular Version:

Angular: 12.0.0
... animations, cdk, cli, common, compiler, compiler-cli, core
... forms, localize, material, platform-browser
... platform-browser-dynamic, platform-server, router
... service-worker
Ivy Workspace: Yes

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1200.0
@angular-devkit/build-angular   12.0.0
@angular-devkit/core            12.0.0
@angular-devkit/schematics      12.0.0
@nguniversal/builders           12.0.0
@nguniversal/express-engine     12.0.0
@schematics/angular             12.0.0
@schematics/update              0.1102.5
rxjs                            6.6.7
typescript                      4.2.4

[alan-agius4]

I have a hunch that this is related to critical css inlining.

Can you try disabling it in your server file.

    ngExpressEngine({
      bootstrap: AppServerModule,
      inlineCriticalCss: false,
    }),

[JoostK]

Heya, I’m sorry to hear you’re having issues after the update. Unfortunately however I don’t think there’s enough information in this report for us to investigate further, so I’m afraid this isn’t actionable right away.

Can you try to determine where the CPU time is spent? Ideally you can attach a debugger and trigger some requests, which could hopefully provide some insights into what’s going on.