Start with: Why is my report so slow?
200 mio. rows, but the question is how many rows are being displayed in your Webi document finally?
Can you create summary tables in the database? Are your indexes really used by the database optimizer engine? Can you partition your database tables? Is the database file holding your database table fragmented or are you suffering from chained rows, etc?
I doubt this will help, as I am assuming the bottleneck is the DBMS (and not BOE)
Andreas 
(BOB member since 2002-06-20)