Apache Drill stuck for long time

[Tridib Samanta]

Hello Experts,
I have recently started exploring drill. I was able to setup a drill cluster of 
two drillbits and query flat json structure of 50 records. When I started same 
query on 10 million json record, it never returned even after 30 mins.
 
What is the way to debug this scenario?
Also is there a way to check how much memory it's using and increase it?
 
 
Thanks & Regards
Tridib