delete

set nocount on 



declare @rowcount varchar(100) ;

while (1=1)

begin 

 delete top (1000) t from perfmon t where machinename is null 

 select @rowcount = @@rowcount 

 if @rowcount = 0 break; 

 RAISERROR(@rowcount, 0, 1) WITH NOWAIT

 waitfor delay '00:00:00.200'

end