The "Most Popular" sort order is based on the "recently_ordered_count" attribute.
Therecently_ordered_countattribute doesn’t exist when we first index products. Instead, we create and increment it as you sell products. If a customer orders two size S blue t-shirts, we increment therecently_ordered_counton this variant by two. We then use this attribute for the Most Popular sort order.
Whenever you run a full reindex, we reset therecently_ordered_countattribute for all products. In other words,recently_ordered_countis a count of all orders since the last reindex, not for all time. However, we preserve the attribute during real-time indexing.
Last updated 10-02-2023.