Working on a small app which can communicate with other instances of the app via MySQL. For example, when USER1 sends a message it is stored in USER2's table with a binary switch set to let USER2's app know there is a message waiting. I want to essentially ping the MqSQL database to see if that switch has been flipped, which would trigger another request for the message.
How frequently could I do this without bogging down the database or causing problems with GET commands colliding? I assume every second is way too frequent. Would every 5 or 10 seconds be okay? This would be for a VERY small number of users, but could potentially be used in the future for hundreds, if possible.
This would be in lieu of setting up server somewhere running an active app to control connections. I'm not sure of any other way to do this from a normal web server.