I have been read a lot of articles to make a good design for my database so I can get the most recent updates for every single user by executing a - kind of - complex query then I send the data using ajax as a JSON to JS file that makes an appropriate edits for the records.
It seems fast but I don't know if it will be as much as fast if the site has a large number of users .
so iv'e started looking for an alternatives . and I found something called NodeJS , I really didn't understand what it is stand for and hope that you can help me with that.
from another hand if the facebook doesn't use a normal db to do whatever he does , then I think there is no way to do it .
helpful link : What's the best manner of implementing a social activity stream?
waiting for your comments.
best regards