Appian log monitoring - Network and DB log

Team,

I have Appian environment managed hosted in AWS. My Appian instance in talking to underlying on-prem data layer via VPN tunneling. Now, I can see extreme delay in production in few scenarios (Around 17 seconds). But when i am looking at performance logs, Appian expression rules & UI are not taking much time to handle request & execute. Can anyone help me on how can i check potential network lag or DB processing lag from Appian logs????? I have check rdms performance logs and they are not taking even a seconds to execute.

Thanks,

Dippoman