I'm sure all of you have seen at some point at some website some message - i.e. you logged in and it stated something like "There will be a planned maintenance downtime at Tuesday 5PM PST". And then you have the tick mark for the message. When you click on it, you don't get the message shown any more.
Now, my question is how to handle this in the database. I.e. if you have 1M registered users and you decide to store this "seen" record for every user you'll end up with a 1M table which has to be read from every time someone logs in. On the other hand, if you have 10 messages like that - of course your table grows much faster. And finally, there could be messages like "Johnny,Harry,Diane and 5 of your other friends have updated their profile."
You could have like 10-50 messages like that daily. What I'm trying to think of is the best approach to this. I've implemented a lot of solutions in the past but I'm rethinking and am wondering of how others in the community are handling problems like that!
Edit: @hakre Thank you for your comment. Actually, I did describe one way I handled it in the question itself. Don't get me wrong but if I propose solutions, answers tend to discuss those proposed solutions which isn't something I'd like.
