So I am working with an inherited SQL query that queries 8 different tables. 5 of which have over a million records.
I have 3 different servers.

Server 1, Server 2 and Server 3. They all have the same data/tables/structure across all servers.
Server 3 has an Iris database engine and the other 2 are Cache 2015.1.4.

I have a problem with views and performance across the servers being inconsistent.

Thankfully Server 1 is the current live server that performs "fast enough".
Server 2 is being synced from Server 1 and acts as a report server.