On the same token, albiet a bit off of the trail. Does anyone have any suggestions for effectively storing fields which can contain BIG5 (IE non utf-8) chars in them, but usually do not? IE Email subject lines or senders.

JSON is picky in this regard, and I don't want to convert the whole string to B64 etc encode/decode it going in and out, as I would like to retain regex search capability for the 99% of email titles and names which are not Chinese within mongo from my php application which lives on the front.