HTML5 introduces new tag datalist, which connected to <input list="datalistID"> provides autocomplete functionality.
Question is - what is the best way to connect this datalist suggestion to MySQL table with high amount of rows (let's say 50K).
The best way to connect it is via the data attribute or the <datalist> tag which takes any URI or IRI to get the data as XML.
You can then change the URI/IRI based on the input value. And also you should limit your resultset to a useful maximum number of lines, you don't want to transfer megabytes just for auto-complete.