As a professional wedding photographer I feel like this is a given, but talking to so many brides it seems way to many "professional" photographers do not offer a second shooter. Let me encourage you to make sure you have two shooters from your photography company especially during your wedding ceremony.
Among the other million reasons your ceremony is so important to have two photographers. First because you'll want both of your expressions as you walk down the aisle.
Second your photographer will probably be in the place to capture you and your wedding party leaving the ceremony leaving those sweet post-ceremony moments un-captured.
Trust me those post-ceremony photos are always the best.
Here is my shot of a post-ceremony moment: