Out-of-memory error with nextJS at run time

[calvinleeto]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/nextjs

SDK Version

9.33.0

Framework Version

Next: 14.2.25

Link to Sentry event

No response

Reproduction Example/SDK Setup

// instrumentation-client.ts
Sentry.init({
  dsn: process.env.NEXT_PUBLIC_DSN
  sendDefaultPii: false,
  beforeSend(event) {
    event.tags = {
      ...event.tags,
    };
    return event;
  },
  tracesSampler: ({ name, inheritOrSampleWith, attributes }) => {
    return inheritOrSampleWith(someOperations(name, attributes) ?? 0)
  },
  integrations: [Sentry.browserTracingIntegration()],
});

export const onRouterTransitionStart = Sentry.captureRouterTransitionStart;

// instrumentation.ts
export async function register() {
  if (process.env.NEXT_RUNTIME === "nodejs") {
    await import("./sentry.server.config");
  }
}

// sentry.server.config.ts
Sentry.init({
  dsn: env("NEXT_PUBLIC_DSN"),
  sendDefaultPii: false,
  beforeSend(event) {
    event.tags = {
      ...event.tags,
    };
    return event;
  },
  tracesSampler: ({ name, inheritOrSampleWith }) => {
    return inheritOrSampleWith(0);
  },
});

Steps to Reproduce

1. npm run build works perfectly with enabling sourcemap and uploading it to Sentry
2. When running the app on production (npm run start), I observe that there is a gradual uptrend for the memory usage of a pod.
3. Eventually, it reached the memory limit of a pod, causing the pod to be killed.
4. node -v // v22.17.0

Expected Result

Memory usage should not gradually increase over time

Actual Result

Fatal Error: Reached heap limit allocation failed javascript heap out of memory
Memory leak should not happen

[andreiborza]

Hey @calvinleeto, we are aware of some OOM limitations with the nextjs during build time (see https://docs.sentry.io/platforms/javascript/guides/nextjs/troubleshooting/#out-of-memory-oom-errors-during-build) but not during run time.

Could you explain further what someOperations does in instrumentation-client.ts?

[andreiborza]

I let my container run for an hour now and see no memory increase. Could you please provide a reproduction repo?

[calvinleeto]

Hey @calvinleeto, we are aware of some OOM limitations with the nextjs during build time (see https://docs.sentry.io/platforms/javascript/guides/nextjs/troubleshooting/#out-of-memory-oom-errors-during-build) but not during run time.

Could you explain further what someOperations does in instrumentation-client.ts?

Thank you for taking a look. someOperations checks whether the current route matches one of the routes we want to sample via expectedRoute.find().

[andreiborza]

I'm afraid we'd need a reproduction repo to figure this out. Can you try removing someOperations and see if you still have a leak?