Paypal PDN - What if customer closes window before redirect?

I'm currently using the Paypal's PDN method of data transfer to keep all my transactions made through the Paypal shopping cart in a MySQL database of my own.

However, when Paypal redirects a customer to my handlePayment.php page, it 开发者_开发技巧takes about 10 seconds to do so. If the customer closed the window, the payment would still be made but the order wouldn't get posted to my database.

Is there a way where I can either:

a) speed up the redirect so it's instantaneous?

or

b) add a description under the store title in the paypal shopping cart, that says "please wait to be redirected after you complete payment?

Do both. Whichever arrives first wins, and the other gets ignored. The payloads are similar, so there's not much code to add.

If you rely solely on IPN, it might not have arrived by the time the visitor gets back to your site (especially if they click to it rather than waiting for the redirect). But if you rely solely on PDN, you get the problem you describe. So do both.