Live site search with a search robot and its own database. Is there a ready solution?

Question

PHP

Hey! You need to do a search on the site, which has about 5 million pages. An interesting ready-made solution: the search engine itself (for example, Sphinx), a spider that will bypass all the pages of the site and add them to the index, and a web muzzle for live search on the site with autocomplete (with the ability to embed the search form anywhere). Is there a ready-made solution out of the box, please advise.
PS. https://www.gigablast.com is ok, but you need to finish a lot + how to embed it in the site design is not clear. Interested in a PHP solution.

Answer 1

https://www.opensemanticsearch.org/

Answer 2

Why don't you like the Sphinx?
It seems to be implemented without any problems