first, Please tuning your DB

Before doing the entire tuning work, our team always like to tune with DB side to guarantee.

Except for planning a good design of the DB schema is important to our performance, we can do several "simple "thing to tune our DB afterwards:

1. open the SQL profiler (in MS SQL server) and walk through all the steps/scenarios with single user thread

2. we expect each SQL statement execution time limited to 20 ms

3. find the slow or questionable SQL statements and then see:

1> proper index missing or should be removed

2> remove unnecessary SQL statements

3> use Nvarchar instead of varchar for the columns...

http://joychester.xhblog.com/archives/2008/372384.shtml

4. then running combined performance tests, no deadlock issue and other gradual increased SQL statements.