Instant Search out of the box? Yes, it is finally here via a flick of a switch by enabling the completely reworked search cache.
How does it work?
It is really simple (on the surface) actually. As the users start using the search, the plugin collects the results, stores them in the cache, which is then very quickly accessed through the client.
This not only greatly improves the repetitive searches performance, but also gives your site more breathing room, as these cached queries does not have to be evaluated. In “Super file” mode (default) the client can directly ask for the cached results, without ever bothering WordPress, saving tons of CPU/RAM usage with it.
Who is this for?
Everyone. No matter your database size, you should enable this cache, it is great for your site UX.
To deep dive into it, you should check the cache documentation, or watch the video below.