Transitioning from Monolith to Microservices?

Hello everyone,

I am currently planning an infrastructure overhaul for our major client. We have a massive monolith reaching memory limits on every peak event. Are microservices truly the answer, or should we just vertically scale and restructure the database layer?

Here is a snippet of our current DB load:

SELECT count(*) 
FROM user_sessions 
WHERE active = true AND created_at > NOW() - INTERVAL '1 hour';

Looking for thoughts from other Lead Architects.