Question

There is Windows Phone 7 app using SQL CE database. I need to delete 1000-2000 rows. There is no other choice than using LINQ To SQL on Windows Phone 7 Mango – SQL CE database.

What I do is extremaly simple (pseudocode):

Entity[] tmp = null;
do
{
    tmp = datacontext.mytable.Where( ...expression here ...).Take(200).ToArray();
    if (temp.Length > 0)
    {
        mytable.DeleteAllOnSubmit(tmp);
        datacontext.SubmitChanges();
    }
} while (temp.Length > 0);

The problem is that deleting 200 rows takes 7 seconds! All time is taken inside datacontext.SubmitChanges().

Is there any way to make it faster?

Any option to use ‘batch delete’? (‘batch_insert’ would be also welcome)

A few technical details:

• DataContext was created by SqlMetal tool and it looks rather heavy.
• Entity has 2 foreign key relations.

Answer 1

Perhaps somebody find it usefull:
Best practises for win phone

I used a few hints from article above plus redesigned algorithm that it tries to modify (recycle) records instead of delete/insert commands. It gave noticeable performance gain, but still comparing the same application on Android and WinPhone it seems WP7 is much slower.

Unfortunatelly I suspect it’s way better to use SqlLite for database heavy apps.