High server CPU usage about crater

[jedwards1211]

Huh, okay, can you export the profiling results and email them to me?

[jedwards1211]

I've seen some background node processes get stuck at 100% cpu on my comp but I haven't figured out why, or if it's related.

[darkadept]

Ok. I can finally reproduce it! It's definitely something with the Meteor login code. I'll try to outline the steps to reproduce it again:

1. git clone a fresh crater
2. add accounts-base to meteor packages
3. run crater server
4. access crater from browser (leave tab open), observe normal server cpu usage
5. stop crater server
6. In browser's tab add the following to local storage:

Meteor.userId                      <some random id>
Meteor.loginToken               <some random code>
Meteor.loginTokenExpires     <some date>

7. close tab
8. start crater server again
9. access crater from browser, observe high server cpu usage

There is another way to trigger the problem:

1. git clone a fresh crater
2. add accounts-base to meteor packages (I think you also need accounts-password for this too)
3. add a link on one of the pages to run Meteor.loginWithPassword('random user', 'random password')
4. run crater server
5. access crater from browser (local storage should be blank), observe normal server cpu usage
6. click on link that runs Meteor.loginWithPassword(), observe high server cpu usage
7. note that local storage is still blank because of non existent random user in login call

I have two profiles recorded, on that is good (with normal cpu usage) and one that is bad (with high cpu usage). I'll email them over to you.

[darkadept]

Oh, I'll just upload the profiles here.

Crater #106 Profiles.zip

[jedwards1211]

Hmmm, I wonder if I'm doing something dumb in the way I sync mongo data into redux that's churning unnecessarily. Expanding the worst offenders doesn't yield much specific information...here's what I see. Did you see high CPU usage from the browser too?

[darkadept]

No. My if I profile my browser it seems fine. Mostly (idle). In fact, if I close my browser the cpu on the server stays pinned.

[jedwards1211]

Weird. Any idea if you see the same thing with an equivalent pure-meteor app?

[darkadept]

I'll check it out and report back.

[darkadept]

Ok. I thought I had tried this already but I obviously didn't. I tried using Node 4 instead of 6. And it's fine now.

Node: v4.7.3
Npm: v2.15.11

This is working fine. I guess Meteor is still on node v4 so there is no real way to test a plain Meteor app with node v6. I'm guessing that if I could it would cause the same problem. Maybe, anyways.

You may want to change the line in the README that says tested on Node 6.

[jedwards1211]

Hmm. Well the CI setup does perform integration tests on Node 6, not that they would catch an issue like this. When I find time I'll try to figure out exactly what's going on