we upgraded from Meteor 2.5.5 to Meteor 2.7 and are experiencing some huge issues with DB (Atlas) connection.
DB calls start to randomly never return any value and hang. We have health checks and I logged inside to see what happens, and simple call like
Users.findOne() just never returns anything, it gets stuck. In our application it seems to happen every 1-2 hours, bringing some of the servers down (happens at different times on each server).
Checking some stats (screenshot above), shows some interesting data. The red line is when we have deployed version 2.7, connections are varying massively and after slowly climbing up, we have an instant drop in connections (when the server goes down basically). Then you can clearly see the point we have rollbacked to 2.5.5. Connections are stable and at the very last moment the increase is when we tried 2.7 once more with the same results, had to abort it yet again.
We have upgraded to MongoDB 5.0 but I can confirm it’s not the problem here because rolling back our application to 2.5.5 fixes all issues even with MongoDB being 5.0 (it’s not a huge deal for us since we don’t use Mongo oplog).
Application for both versions is the exact same code, just with Meteor version updated.
There are no useful logs at all. It just stops working.
Anyone experienced anything like that? Any help would be appreciated.