ssr: memory and cpu problem

[xsbchen]

Version

2.7.0

Reproduction link

https://github.com/vuejs/vue-hackernews-2.0

Steps to reproduce

1. git clone https://github.com/vuejs/vue-hackernews-2.0
2. npm i
3. add beforeRouteEnter event to src/views/CreateListView.js:

  beforeRouteEnter(to, from, next) {
    next((vm) => {
      console.log('before enter user view');
    });
  }

4. add console.log to vue-router.common.js line 2058:

function poll (
  cb, // somehow flow cannot infer this is a function
  instances,
  key,
  isValid
) {
  if (instances[key]) {
    cb(instances[key]);
  } else if (isValid()) {
    setTimeout(function () {
      console.log('vue-router poll');
      poll(cb, instances, key, isValid);
    }, 16);
  }
}

5. npm run dev
6. open http://127.0.0.1:8080/

What is expected?

memory can be gc collected

What is actually happening?

memory and cpu grow up, and it keeps printing vue-router poll

---

[Mart-Bogdan]

@xsbchen @tangyue0924
I just had simmilar issue, fixed it, by using runInNewContext: false in createBundleRenderer call, from server entry point (server.js)

https://ssr.vuejs.org/en/api.html#runinnewcontext

Without it. VueRouter's Mixin was added to Vue multiple times!

[xsbchen]

@Mart-Bogdan it seems that newest version had fixed this problm

[Mart-Bogdan]

@xsbchen I was at 3.0.1

[xsbchen]

@Mart-Bogdan how to reproduce？

[Mart-Bogdan]

in case of SSR

  return createBundleRenderer(bundle, Object.assign(options, {
    cache: LRU({
      max: 1000,
      maxAge: 1000 * 60 * 15
    }),
    basedir: resolve('./dist'),
    runInNewContext: true // HERE!!!!
  }))

I'm not user if it would reproduce on heackenews https://github.com/vuejs/vue-hackernews-2.0/
But I've good memory leak. Vue instance was same, and mixin was regeistered multiple times.

Perhaps bug of SSR team.

Just letting this info here, in case someone would have same bug, and find this post in Google.

Perhaps add some mention to disable context in readme, don't know :-)

[posva]

A boiled down repro instead of a whole app would help to identify the problem, thanks

[ryouaki]

I got the same issue, and no idea.........

[Mart-Bogdan]

@ryouaki
Have you tried disabling creation of new context each time on ssr?

[ryouaki]

no，this way chould fix this problem？ but，in my app ，i have a lot of request in one time from client side。if run in new context it will cost more cpu。
and i try fix by modify the code of axios。axios pr. this way fix this issue。but axios team no response。this can kill the block event.
i think the reason is not from axios。but this way help fix this issue。

[ryouaki]

@posva I think thie issue should be reopen. I got the reason of this issue.

This issue will appear only on ssr application. In my project ,I got this issue. I add beforeRouteEnter fouction on my Vue component which render on server side . and got Infinite loop with function poll.

[posva]

A boiled down repro instead of a whole app would help to identify the problem, thanks

if you have an infinite loop, it's probably next not being called without arguments