Quick note about "ctx._now" w.r.t "_update_by_query". Follow-up to Elasticsearch Update by Query using CTX
I saw this too, today, and was surprised since "_update" does support "ctx._now", but "_update_by_query" apparently does not. Solution may be to just use "currentTimeMillis()".
At first I thught that's a bug, but the "_update_by_query" documentation does not really mention it, unlike "_update".