We have a meteor app in production (wekan if someone knows), and since few days, we have performances problems. We updated our app in the last release (from meteor 1.6 and mongo 3.6 to meteor 1.8 and mogo 4.0.11).
The app works with Docker (4 replicas for the app and 1 for the db). When we inspect their stats, we can see cpu overload and a large amount of data extracted from the db !
We first thought that the problem came from indexes, but there are created and used. After searching, we found that Meteor can perform two actions for subscriptions. The poll and diff and seeing the oplog. First, we would like to know if enable the oplog will improve the situation? Then, how we can do it because all our tries failed.