Quote Originally Posted by disciple View Post
The main problem (as I looked back at messages I saved) was that at the end of the sale my server load went through the roof. It was due to mysql processes on the store database.
The only thing that happens in the database when a sale expires is a reset of prices without the sale applied.
How many products are in your database?
Do you use a lot of attributes?
Do you have attribute-dependent pricing ?

What happens if you (do a database backup first and then) go to Admin->Tools->Store Manager and click on Update all Products Price Sorter ?
If this step is the problem, well, you might wait a long time.

24 hours seems absurd. Especially since PHP is likely to time out after 5 minutes, or even 30 seconds depending on the server configuration.