From memory I always thought it was the Mig-17 fresco which was the first russian fighter to go supersonic. I looked it up and what the sights were saying was that:

a. it could only go supersonic for a little while and
b. it was not a full scale production fighter*

*however in some wars we encountered more mig-17s than mig-19s, so I guess it was a semi-full production fighter.

All in all Migs 15-19 are all very similar. The mig 17 being a "refined version" of the Mig-15 and the Mig-19 being considered by some as "virtually identical". (all statements that I would loosley agree with).

http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=mig-17+fresco+supersonic

Remember to be careful about our designations of foreign weapons. These are the NATO designations, not the real soviet names. Just because something is designated with a higher number does not necessarily mean that it is newer, it just means that we found out about it later.

Regards,
Justin Kelly