What Criminal Record info is visible to the US border?

I received a condition discharge over 4 years ago. I have since done a CPIC search (reason for search was listed as travel") and it was clear. As well I got a job in insurance, and they had done a cpic search on me as well. I am wondering what they do at the us border when you cross from canada. Do they do a CPIC search? Since I have been arrested and fingerprinted, will my name come up when they search? When it was purged 3 years after my conditional discharge was granted, can they not see my name at all? Any advice would be great!