Analyse memory leak in node js

We have built a node ( currently running on v12.18.3 ) application in Ubuntu 16.04 . We have two databases connecting to our application. 1. PostgreSQL for master data (v9.6) 2. Cassandra for reporting Initially everything was good. But when user base increased, we started facing issues in memory management. "Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory." We have made the below changes recently: 1. node running on forever changed to pm2 2. Node v8.9.4 to 12.18.3 3. Postgresql v9.5 to v9.6 4. node args : --max_old_space_size : default 1.5gb to 8gb. After the variables, we have got some breathing time but still the problem persists. We have consulted many nodejs programmer but still dint get any way through. We are looking for an expert in nodejs with 4-5+ years of experience in node who can solve and guide us through this issue mentioned above.