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0 I am working on a simple chat service ran by Spring Boot 2.1.1 with WebFlux, Reactor 3.2.3, Mongo 3.8.2 and Netty 4.1.31. Each chat room has 2 collections - messages archive and a capped collection with current events (eg. new message event, user typing indicators etc.). The capped collection has 100 elements and I am using tail() method of ReactiveMongoTemplate to retrieve latest events. The service exposes 2 kinds of endpoints for retrieving the recent events: SSE and for polling. I have done some stress testing with 2000 concurrent users which apart from listening to the chat, were spamming tons of events. The observations are: polling every 2 seconds brings a bit of stress to the service (~40% CPU usage during the test) and almost no stress to the MongoDB (~4%) listening via SSE maxes out the MongoD...