To achieve the best performance possible, we pre-compute your sort criteria at indexing-time. This is an optimization to ensure you will always have outstanding performance at query-time. The consequence of this approach is that you cannot change the sort criteria of an index at query-time: each index has its unique ranking strategy and you need to have one duplicate of your data per sort criteria. To sort your results with a specific attribute (like price or timestamp) you can update the default list of ranking criteria to include your attribute first:
For simplicity’s sake, we recommend to name your replica with a prefix/suffix describing its ranking strategy: products_relevant_desc, products_price_asc, products_price_desc… This way, it’s easier to target the right index when you make the search calls.