Microservices: Software decomposition is not for performance, it is for the human brain
You can actually prove that most software systems would work faster in a monolith than in a microservice architecture. Just put back together all the microservices in a monolith, mentally. Replace all the REST calls with direct Java calls, this should eliminate a lot of extra work to serialize/deserialize. The resulting system will consume less resources overall just by less serialization. The latency should be smaller without the network calls. If you eliminate all the workarounds added just to make the distributed transactions to work, the performance should be significantly higher - with a proper load balancing of course. There are some edge cases, like if your resulting application does not fit into DRAM, however this is rarely the case. The horizontal scalability should still work is you deploy enough of those monoliths and correctly balance the work among them. Of course, the starting time might be higher with the monolith. The risk for Out Of Memory from one module to the o...