flex datagrid在检索数据时冻结

i have a datagrid which grows in size depending on the result of a call to my db. The call to the database returns an object with 30+ values for each row. When the number of rows returned exceeds about 80-90 the datagrid renders odd. It displays the first 50-60 rows fine but then it displays blank rows and they even continue to display outside the border of the datagrid.i have a datagrid which grows in size depending