Hi, I'm a new member here and I'm a beginner in SQL query. Recently, I've built a web application using ASP.NET 2.0 and SQL server 2005 express and in my client, they use SQL server 2005 (I don't know which version but I'm sure it's not express edition). I've deployed my application a month ago and now they complain me about the performance degradation. Since I know just a basic SQL query knowledge and I do know the low performance cause might be the huge data entered there, I would like to know what would be the other cause of the low performance problem. Anyone can help me? And do you have any suggestion on how to fix the poor performance? FYI: All the tables already in 3NF and I broke the rule of 3NF a little (I make a calculated column in some tables because I need it for complicated process). Almost query I built is in stored procedure and no dynamic SQL in stored procedure at all.