Private rooms work so that if there's no moderator activity in them for seven days, they're automatically frozen. This doesn't prevent the moderators from using them, as mods can still chat in a frozen room, but it does prevent anyone who isn't a moderator but was invited to that room from using it. This includes moderators of sites other than the one the room is parented on.

Anyway, the moderator room on one of the sites I use is really low-use and it gets frozen and unfrozen a lot because I don't really like talking in a frozen room even if I can. As such, I have a bunch of data points of when the last message was posted and when the room is frozen. I was looking at them the other day and I noticed that the time of the last post was not the same as the time the room was frozen seven days later, which I half expected.

My second guess was that there was a script that ran at a scheduled time each day and closed any rooms that were inactive... but in that case, the close messages should all be posted at the same time.

I did a search for the word "automatically" to see all of the messages about the room being frozen and I found something really odd...

All automatic freezes in private room

  1. The times are mostly all different except for in September 2016, when three of them happened at the same time... but not seven days apart.
    • Sept. 5, 2016 - 2:47 PM
    • Sept. 7, 2016 - 2:47 PM
    • Sept. 11, 2016 - 2:47 PM
  2. The username of the feed that posts the message changes from "Feeds" to "Stack Exchange".
  3. The message isn't always the same. Once, in January of 2017, the message was different and included a link to this page... which is a bit out of date and doesn't have anything to do with private rooms (though the message doesn't specify "private room" the way the others do).

What you can't see in this image is the comparison between what time the last message was posted and when the room was frozen. Sometimes it was a delay of seven days and an hour or two or four or six... but sometimes it was almost a full day "tardy", if you will.

Time between room being unfrozen and frozen

If you do the math, which I did with a neat widget I found, you get a difference of 7 days 16 hours and 3 minutes.

So, how are our mod rooms frozen? What's the explanation for the random times between the last message and the room being frozen and why was the room being frozen so often in September 2016 - two of the times the room was frozen (the 7th and 11th) were after 18-19 hours!

I'm starting to think I see feet behind the curtain... can it be?


2 Answers 2


The script that freezes inactive rooms (and deletes inactive rooms if they haven't gotten much of any activity, ever) runs once a day. So if a given room hits the threshold for culling 1 second after the script runs, it'll get very nearly a full extra day of not being frozen before the job runs again and catches it. That explains most of the timing issues you've observed...

The script always does its dirty work as user #-2 (unless a chat dev runs it manually, but that shouldn't happen much). User #-2 is currently named "Feeds", but it could be named "Stack Exchange" or "Ax Man McGee" if some snarky moderator decided to name it such. Given this user is also used as the default for posting feed messages into rooms and introducing the context of comments moved to chat... You shouldn't rename it. But if you did, and it stayed renamed long enough to freeze your room... You'd forever see the action under that name in your transcript.

That just leaves the rules for various types of culling. First, to be eligible for culling, a room has to meet one of the following conditions:

Of the eligible rooms, the following forms of culling may be applied, in this order:

  • Inactivity deletion The room will simply be deleted if it has been inactive for 7 days and fewer than 15 messages by 2 users have been posted in it, ever.

  • Inactivity freeze The room will be frozen if it has been inactive for 14 days.

  • Inactive moderator freeze The room will be frozen if it is a private room and no moderator has said anything in the past 7 days.

Note that unfreezing doesn't count as saying something... So if you unfreeze a room and don't post anything, it'll get frozen again within 24 hours. And if a room containing only moderators gets frozen for lack of mod activity (7 days since last message) and a moderator unfreezes it 7 days later (now 14 days since last message), it'll just get frozen for general lack of activity the next time the script runs (again, within 24 hours of you unfreezing it).

I believe this should explain everything you've observed, with the exception of the feet behind the curtain. Ignore those.

  • 1
    But... if the script runs daily... why aren't the freezings around the same time each time it happens?
    – Catija
    Commented Dec 8, 2017 at 23:12
  • 10
    Computers are fickle creatures, prone to impulsive actions and flights of fancy; who can predict what they might do, or when they might do it?
    – Shog9
    Commented Dec 8, 2017 at 23:23
  • 1
    Oh, OK! That makes total sense. I should have figured that out for myself.
    – Catija
    Commented Dec 8, 2017 at 23:25
  • @Makyen You sure your testing was correct? Your edit was just rolled back by a staff member. Commented Aug 17, 2021 at 22:38
  • 1
    It was rolled back because we fixed a bug, @sonic.
    – Catija
    Commented Aug 17, 2021 at 22:41
  • @Catija so just to make sure, now if a user talk every day in a private room, it's not enough and the room will be frozen unless a moderator won't talk as well? Commented Aug 18, 2021 at 8:14
  • 2
    @ShadowWizardWearingMaskV2 Correct. A moderator must be active in the room. Private rooms are for moderation purposes only. If there's no mod activity, the room will freeze.
    – Catija
    Commented Aug 18, 2021 at 11:55

I've been able to explain the time stamp of the script running changing over time by plotting the day of the year compared to the time of the post, decimalized by adding the 24 hour hour to the minutes in the form of n/60 (e.g 4:12 pm --> 16:12 --> 16+(12/60) --> 16.20).

I excluded the three events occurring at the same exact time and the August event that crossed the date line. Negative numbers are 2016 and positive numbers are 2017.

Graph of chat room freeze events

While there are some numbers that deviate from the pattern slightly right around the beginning of the year, all of the rest of the numbers form a nearly perfect line with a trendline with an R2 value of 0.97.

You can see this more clearly when I remove the three events in December and January... because even scripts get a bit lazy during the holidays.

Graph of chat room freezing events without December and January

The trendline now has an R2 value of 0.99956!

So, given this, it seems safe to assume that there are no feet beyond the curtain, merely a drifting script.

  • 1
    You surely worked really hard to find something rather... not so important. Well done! :-) Commented Dec 12, 2017 at 7:43

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