Q1: Many Monks utilize mySQL for projects from trivially small to gigundo. Though I am not one using large data sets, I suspect you'll have no problem. But an authoritative answer will have to come from another responder... and frankly, I suspect you'll do better and/or quicker by posing Q1. on a site specializing in mySQL or, perhaps, by reading mySQL's online docs.

Q2: DBI and DBD::mysql make a tag-team that should make your work fast and simple.

Welcome to PM... but strongly suggest you read On asking for help and How do I post a question effectively? and try an outside search engine or Super Search before posting such a broad question with (implicit) answers all over this site.

Update: changed links Q2 answer to aliases for readability.