Hi,
Category filters can be excessive indeed, especially if you have a lot of categories (hundreds) and lot of posts to filter (thousands).
It is always recommended to use the least amount filters if possible, with the least amount of elements.On the server side this is optimized as much as possible, but some use cases can’t be optimized any further. The worst of all can be the checkbox type filters, when not all of the categories are used, or they are in a custom order. If you can’t avoid using filters, I recommend the following best use cases, to get the best possible performance:
– For checkbox layout, try having them unselected by default: https://i.imgur.com/NkK395W.png
– Also for checkboxes, reduce the number of terms visible in the filters
– Consider using a drop-down or a drop-down multiselect layout instead for a large number of visible terms, it is much more efficient in terms of performance: https://i.imgur.com/g7XkCzj.png
With the drop-down search the user can choose the exact categories, reducing the information sent to the server greatly.
– If can be avoided, do not use any taxonomy based exclusions nor inclusions in combination with the filters.
– Use the caching feature. Repetitive queries, including filtering will be cached, and no longer require table joins to get the items
These can radically affect the overally performance of the queries.
