We experience a situation , when admin was canceling an order at the same time a customer place an order and Stock quantity history changed as follow:
1 - product attribute combination was 12
2 - a customer bought 1 and stock quantity history became 11
3 - admin cancel an order with quantity of 1 and stock quantity became 13
I thought we should put a LOCK for AdjustInventory method but it may cause slow order placement when several orders are placing at the same time.
What's the solution and what does the big online stores like Amazon and eBay do?