Environment plays an important role in the
results and effectiveness of test, particularly
in the area of performance testing. Some of the
factors will be under our control, while others
will not be.  These may involve the DBMS, 
the operating system or the network.   
Some of the items that we cannot control
unless you can secure a stand-alone 
environment (which will generally be unrealistic) are: 
-        Other traffic on the network   -      
Other process running on the server   -       
Other process running on the DBMS