There is a query in Producution which was running fine for past 3 years. But for the past 2 days it is taking more than 10 minutes. earlier it used to take 2 seconds. Copied the production data to Development env. Same problem occured in development env. Did a dbcc reindex on the major tables which the query was using. In development env query performance came to 2 seconds based upon this analysis ran the dbcc reindex in production , but the still the query takes 10 minutes. Scan density in major tables in production is fine. we have weekly reindex jobs on these tables to. The table has more than 5 million records. What is the problem going on production ,Can anyone please help on this ASAP?