Currently, the OrderRefresh service calls $order_item->hasTranslationChanges() for each order item, to detect whether the order item needs to be saved.
The problem is this calls OrderItemStorage::loadUnchanged() reloading each order item from the DB (sometimes from the static cache, but somehow seems to load from the DB according to several requests I've been profiling with Blackfire).
I'm thinking we could store the original order items in an array, then artificially set $order_item->original right before calling the hasTranslationChanges(). This should prevent the need from reloading each order item from DB...
MR to follow (I'm hoping this won't break anything)...
Active
3.0
Order
Issue #3532292 by jsacksick: Performance improvements to OrderRefresh