Is this expression a confusion of a German or Yiddish expression?

German phrase is wie geht es Ihnen? (literally, how goes it to you?). I'll take a look for the Yiddish, but I think it's similar.

Interesting question. I couldn't find much, but I did find this reference from LanguageHat. Here is the comment posted by Toby on April 5, 2005:

"My Russian and Yiddish speaking grandmother would always ask, 'So, how's by you?', meaning how's everything with you and at your house. We always thought that form was borrowed from Yiddish. But as I've studied Russian, it seems to be translated from Russian."

I don't know any Russian idioms, but "Kak dela?" is the standard "How are you?" greeting, and that surely does not sound as if it could have been the source of the expression. Do we have any fluent Russian speakers lurking on this board? If so, now's your chance!