With extra tax revenue rolling in, Fairfax County officials are expected to give county employees their first raise in three years. It’s uncertain how much additional money the county will collect from sales and business taxes, but it’s likely to be enough to cover the $10 million cost of giving county workers a 1.12 percent raise, said Susan Datta, the county’s chief financial officer.

That additional revenue, which will be tallied in mid-July as the fiscal year comes to a close, represents higher-than-expected revenues for fiscal 2011 and lower-than-expected costs.