i am creating a social network with php, i use longpolling and also need to have live comment replies, i could query my database for new replies in the longpolling page, but that would exhaust my database, so to avoid this, i create an shm segment for every comment, and then whenever there is a new reply to that comment i use the created shm to send the id of that reply to all users who are viewing the comment. so you get my idea. is creating a SHM segment for every comment going to cause me any problems ? for example if there are a million comments, what will happen ?