CSV is out of the question, because you can't do a thing with it inside the database.
Ofcourse poosgresql can handle it 🙂
On change you may want to consider though: create a seperate 'words' table and link to that instead of storing the keyword over and over. A reference is an int, which is 4 bytes, whereas most words are >4 characters.
Also, don't store a word twice for the same page. Instead, store the number of times that the word appears on the page.
