Where To Save Messages For Chat/Shout-Box?

I'm going to create public chat/shout-box that will refresh after several seconds (almost like IRC or something).

My plan:

1) HTML form,

2) With JavaScript disallow to normally submit that form,

3) Save submitted message (here come problems),

开发者_StackOverflow社区

4) Show new messages (with AJAX, I guess);

I'm not sure where to save those messages! I could save them in database, but... that may be very slow, because each user request new messages each several seconds, right? I could try optimize, but I'm not sure how... Maybe I could save those messages somewhere else?

---

I don't see why the database access would be slow (assuming it's local to the webserver) - I mean the data would certainly be stored in RAM if the data is accessed permanently anyhow and databases are quite optimized to handle queries efficiently.

Obviously you could store the data in your own datastructure and then save that to the db regularly, but you're reinventing the wheel and if your server crashes you may lose data.

What I personally would do is push data to your clients and NOT pull data from them (which seems what you're planning to do), that way you'd only have to send data whenever someone logs in or a new message appears - both situations that should happen not that often.