Memory usage and sessions quadruple after upgrading to Meteor 3

help
1

Hello, recently I upgraded our app to Meteor 3 and app performance took a hit.
My app is deployed to a self managed server using meteor-up.
When checking the server using lazydocker, there are errors like Javascript heap out of memory and Mongo Pool Connection error.
MontiAPM shows a huge increases in memory usage and total sessions after the meteor 3 deployment, screenshot below.
I think there might be a memory leak, though not sure where to start looking and how.
Any ideas?
Thanks

MontiAPM
MontiAPM1756×829 150 KB

2

What is your mongo pool maxSize?

3

I have maxPoolSize=150

4

Try lowering that, for example setting to 25. Then tune / increase the size after measuring resource usage.

This will obviously throttle db operations and potentially increase pool queue size and checkout times.

But start somewhere lower, then tune from there.

5

I will try that, but still why would that causes such a huge different between Meteor 2 and 3?
The mongodb settings on Atlas is unchanged.

Here is the screenshot on MontiAPM for the Mongo pool size and checkout times. The red vertical line is when the app is upgraded to Meteor 3.

Mongo max pool size
Mongo max pool size1010×792 84.6 KB