is MySql good for large databases?

[aryafilan]

I work for a company and we are always accessing an external site for information. The site was developed by an antiquated software development company who doesn't even have a website. They pretty much have a monopoly in my state since the content provider for the database only uses this extremely dysfunctional site to upload their data. The problem with this website is that it is so slow it's not even functional.Having controlled for things like Connection speed and Browser type, it is clear that the problem lies within the website itself. So, I am thinking about redoing the site and then offering it to the content provider as a means for uploading their data. Basically, this project requires a very large database to store hundreds of thousands of names, addresses, and other types of data. My only experience with databases is MySql, and really my only experience with dynamic content is PHP. So, yeah, I'm trying to figure out if the old PHP + MySQL combination is suitable for storing and representing large amounts of data. I have only done this on small projects, but I think the whole HTML templates with placeholders for the dynamic content would work fine.Of course, I truly don't know why this website is so slow. Maybe it's not the DB at all. Maybe it's the server or something else. But the key thing I am trying to accomplish is to improve upon the speed and functionality of this site. I have no experience with other types of databases, so any tips / advice you can offer for doing a project like this would be greatly appreciated. Also, any tips regarding how to generally make a fast and functional site that would need to represent dynamic data from an extremely large database would also be helpful.*Edit: I am learning python so if you think this would be a better side-scripting language then I can certainly try to implement something different than the initial plan above.