Love Xapian, been using it for many years via notmuch (mail) and recoll (document indexing, mainly PDFs in my case). It's been trouble free and very performant

Love Xapian, been using it for many years via notmuch (mail) and recoll (document indexing, mainly PDFs in my case). It's been trouble free and very performant, a real workhorse. https://notmuchmail.org/ https://notmuchmail.org/ https://www.recoll.org/ https://www.recoll.org/