Linq to Sql: How to quickly clear a table

You could do a normal SQL truncate or delete command, using the DataContext.ExecuteCommand method:

context.ExecuteCommand("DELETE FROM Entity");

Or

context.ExecuteCommand("TRUNCATE TABLE Entity");

The way you are deleting is taking long because Linq to SQL generates a DELETE statement for each entity, there are other type-safe approaches to do batch deletes/updates, check the following articles:

• Batch Updates and Deletes with LINQ to SQL
• LINQ to SQL Extension: Batch Deletion with Lambda Expression