The major problem that flash sale sites face is the sudden and large amount of traffic. Generally, people are notified in advance about the time of the sale, so at that exact moment, a large number of customers hit the site to purchase the objects on sale. Therefore, we see a sudden spike in traffic and low traffic when there is no flash sale happening.

Another problem is that, as soon as a product is sold out, it should be moved to the bottom of the search result. We have already seen how this situation can be handled in the previous section. However, this requires very frequent updates to the Solr index. Ideally, as soon as a sale happens, the inventory status should be updated in the index. This is a general problem, but with flash sale sites, the problem becomes more acute. This is because at the time when the sale opens, there is a rush for a certain product. Moreover, the site can lose customers if inventory is not properly tracked and reported...