Calling large amount of urls listed in a file

I got a set of 3 million customers each with an url that contains its unique identifier (hash) and some other variable values. Through calling each url I can set the values for the variables so my website displays personalized content for each customer. I need to be able to make this 3 million url calls in a fast way, having them in a plain text file or an oracle DB (what is better).

Can you help me with ideas to solve this problem? I am exploring curl option but still not sure if is as fast as I need.

Any ideas?

thanks.

PS: I'm working in windows 7.