'x new comments, show' - time elapsed?

July 7, 2012 12:39 AM

When viewing threads on the mobile version of the site, how much time elapses before the 'x new comments, show' thingy displays? Same question for 'No recent updates. Reload to check for new comments.' (unless the time elapsed is the same for both).
posted by paleyellowwithorange to MetaFilter-Related at 12:39 AM (10 comments total)

This is a question for pb, and it's a little after 1 am for him now, so he'll be by in the morning to answer this.
posted by taz (staff) at 1:07 AM on July 7, 2012

Rightio. I figured as much, but in the meantime I thought someone else might happen to know.
posted by paleyellowwithorange at 1:16 AM on July 7, 2012

There's no set time. When you load a thread, the page starts checking in the background to see if there are new comments. I think it waits 60 seconds before it does its first check. If there are new comments, it shows the 'new comments' message and checks again in 60 seconds. If there aren't new comments, it checks again in 100 seconds. If there aren't any comments then, it checks again in 140 seconds. Repeat. If it checks 20 times and doesn't get any new comments, it displays the 'No recent updates, reload' message.

So the amount of time it takes to get either of these messages will depend on how fast the thread is moving.
posted by pb (staff) at 3:44 AM on July 7, 2012 [2 favorites]

oh, and this feature doesn't have any difference between the desktop and mobile versions.
posted by pb (staff) at 3:45 AM on July 7, 2012

Wow, thanks, pb, for that informative answer.

So, dusting off my math brain, the number of seconds before the 'No recent updates' message displays would be 60 + 100 + 140 + 180 + etc. for 19 additions of 40 seconds after the initial 60 second check, i.e. 8800 seconds, or 147 minutes, or 2 hours, 27 minutes and 40 seconds.
posted by paleyellowwithorange at 4:09 AM on July 7, 2012

That sounds right, assuming there are no comments added after you open the thread. Once a comment is added the timer is reset.
posted by pb (staff) at 4:19 AM on July 7, 2012

No exponential backoff? Huh.
posted by ryanrs at 12:37 AM on July 8, 2012

What do you mean by backoff, ryanrs? Is that different from the time decay I mentioned?
posted by pb (staff) at 6:13 AM on July 8, 2012

pb: Similar to what you do but using exponents and not just adding 40 seconds every time. You can have better responsiveness early on and less wasteful traffic when nothing is happening. You might check for new comments first after 2 seconds, then 4s later, then 8s, then 16s, then 32s, then 1m 4s, then 2m 8s, 4m 16s, 8m 32s, 17m 4s, 34m 8s, 1h 8m 16s, 2h 16m 32s. Only 13 requests to do that versus your 20 and much less latency in threads where stuff is happening.
posted by floam at 7:37 PM on July 8, 2012

ah ok, thanks for the explanation floam. I think it's working ok as is, but I'll give it some thought.
posted by pb (staff) at 8:20 PM on July 8, 2012