It takes a long time to insert the first record each time when the program start

I am using VS2005 (VB) to develop a PPC WM5.0 Program. And I am using SQLCE 3.0. My PPC Hardware is in 400MHz.

The question is when the program try to insert the first record into sdf database after each time the program started. It takes a long time. Does anyone know why and how can I fix it?

I will load the whole database into a dataset when the program start and do all the "Insert", "Update", "Delete" in this dataset and fill it into database after each action.

cn.Open()
sda = New SqlCeDataAdapter(SQL, cn) 'SQL = Select * From Table
scb = New SqlCeCommandBuilder(sda)
sda.Update(dataset)
cn.Close()

I check the sda.update(), it takes about 0.08s for filling one record into database normally. But:

1. Start the PPC Program

2. Load DB into dataset

3. Create a ONE new record in dataset

4. Fill back to DB

When I take this four steps everytime, the filling time is almost 1s or even more!

Actually, 0.08s is just a normal case. Sometimes, it still takes over 1s to filling back a dataset which only inserted one record when the program is running. (Even all inserted records are exactly the same in data jsut different in the integer key)

However, when I give up the dataset and using the following code:

cn.Open()
Dim cmd As New SqlCeCommand(SQL, cn) ' I have build the insert SQL before (Insert Into Table values(XXXXXXXXXXXXXXX All field)

cmd.CommandType = CommandType.Text
cmd.ExecuteNonQuery()
cn.Close()
StartTime = Environment.TickCount

I found that it is still the same that the first inserted record takes more time, but just about 0.2s. And the normal insert time is around 0.02s. It is 4 times faster!!!

Last example does not include looking for updated rows in the DataSet and generating appropriate commands. Since it does less, it's faster.

sql