Load test with meteor-down and strange slow db queries


#1

Hi all,

I’m new here, so apologies if this is not the correct category to post this.

We have an app deployed on Heroku connected to a DB hosted on Atlas. I’m currently making load tests using the meteorhacks:meteor-down package, and kadira (self-hosted now) to monitor the performance.

I made the load test so not every action is executed one after another, to simulate a more realistic behavior between calls, using a sleep function like this:

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

What I’m finding is that my methods are taking very long time even when using a load of user small as 500, and when I check on kadira, it seems that some db queries are taking way too long for what they are doing, and I don’t understand why.

For example, in one of my insert methods, I’m getting these numbers:

How is it possible that is taking so long so perform a findOne by ID on the users collection, or insert a document in the classrooms collection? Where should I look for bottlenecks of performance issues that could cause these?

Thank you,
Nelson


#2

This sounds like it could be your Meteor CPU maxing out at 100%. I had a similar phenomenon happening in my app. See this thread:

https://forums.meteor.com/t/poor-galaxy-meteor-performance-serving-small-bursts-of-users-load-test/38671