Summary Row in DataGrid-view on SQL-Server tables builds Aggregat on Client instead of using serverside aggregate-functions
When using the summary row in a DataGrid-view with SQL-Server-tables or views the Aggregate is build on the clientside, which is very slow when rowcount is high. Continually all rows are fetched to build summary. When ready, it starts again.
Please use sum(), avg()...-Aggregate-functions to get the summary.