Remove table_exists? which uses expensive fall back to columns. I'm not sure this is needed? No tests fail when I remove it and arnt you supposed to put :establish_connection(key) in your models when you want to connect to different databases? Removing this saves 20 seconds on test time and helps performance.

Author: metaskills

lib/active_record/connection_adapters/sqlserver_adapter.rb

@@ -577,11 +577,6 @@ def tables(name = nil)
         end
       end
 
-      def table_exists?(table_name)
-        #If the table is external, see if it has columns
-        super(table_name) || (columns(table_name).size>0)
-      end
-      
       def columns(table_name, name = nil)
         return [] if table_name.blank?
         cache_key = unqualify_table_name(table_name)