So, I thought at first it might be number of posts, but that doesn’t seem to apply as I’ve seen threads that run 2 pages and don’t have it. It must be decided by the server, but by what criteria?
If it thinks there are unread posts.
This is somewhat faulty because you don’t have to read or even see a post for it to be considered read.
What’s more, if you click on ‘View First Unread’ several times, it returns to the same post long after you have read it. I think it is relatively unintelligent and works on a time stamp.
Any thread that has a post later than the time of your last visit (seen at the top of each page) will show the View First Unread icon.
When you leave the Dope the server assumes that you have read all the threads and will reset them from that time when you next arrive.
Why does ‘SNAFU’ keep running through my head?
At any rate, thank you for your answers.
If you think the boards are slow now, just think how much worse it would be if the database had to track every thread that each user visited and what time you last went there, and then check your data every time a page was displayed.
I agree that the present system is not the ideal, but it’s probably the best compromise under the circumstances.
I remember reading on the vBulletin message board, that the developers considered the algorithm “broken” and were exploring other methods. But as you said, other methods would likely gobble more resources.
Might there be some way to do it client-side via cookies?
Even with cookies, that’s a lot of data to be sending back & forth to the server every time you load a page.