This is a very common question which i have always heard from the CLIENTS :- "There has been no changes,no alterations , no new indexes , no parameter changes then why the HELL is this query running slow today??Did you check the explain plan.It was running good last month...WHY NOT TODAY??" READ THIS - http://richardfoote.wordpress.com/2010/02/16/how-does-an-execution-plan-suddenly-change-when-the-statistics-remain-the-same-in-limbo/ … Continue reading No Changes,No Alterations..Explain Plan Suddenly Changed !!!!