Increased resource consumption on pmm server with Remote PG monitoring

Impact on the user:

• Users are unable to use the same PMM server to monitor remote PG (RDS) servers on the hardware worked well for 500 servers before  

Steps to reproduce:

1. setup pmm 2.18
2. Add 500 Remote PG instances for monitoring (RDS based)

Actual result:

• increased Network usage comparing to 2.16
• big memory usage compared to 2.16
• the server is able to monitor 12  Servers correctly  

Expected Result:

• work  well 

Workaround:
downgrade to pmm 2.16

Details

Original report: