Timeline navigation misbehaving starting from 10000 posts

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AI-generated summary

User Canapin reported a timeline navigation issue in topics with 10000+ posts, specifically that the timeline cursor doesn’t update after dragging and dropping the cursor until manually scrolling again. They also noted that increasing the auto close topics post count setting and changing the short progress text threshold didn’t resolve the issue.

User Falco explained that this behavior is due to the way Discourse handles large topics to preserve performance, citing previous discussions (The MEGATOPIC: public good, or public menace?) where the development team mentions that features are intentionally limited in megatopics to reduce server load.

Canapin acknowledged the reasoning behind the limitations and understands that the issue is minor and rare, occurring naturally with the default Discourse settings. They noted that adjusting the reply limit to 9998 instead of 10000 would prevent the issue, but accepts that this is not a significant concern.

1

Hi.
I noticed after an import that the timeline navigation don’t work properly on 10000+ posts topics.
If you drag’n drop the cursor on the timeline, it will scroll to the post, but won’t update the timeline cursor until you scroll again manually:

My max reply limits is the default one: 10000. So it shouldn’t be an issue…
Except that Discourse closes a message at the post number 10000, and add another reply (automatic closure), which makes 10001 posts.

But even at 10000 replies, the issue occurs.
However, the issue disappears as soon as delete posts to have 9999 replies (including the automatic closure message):

So, the issue occurs naturally when the topic reaches 10000 replies, and not only for existing megatopics.

I increased the auto close topics post count setting but it didn’t resolve the issue.
I also tried to change the short progress text threshold and it didn’t help either. Weirdly, even by increasing this setting to 15000, the timeline cursor doesn’t show the date on a 10000 posts thread :thinking:

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But that may be another issue.

2

This is because

We remove a lot of features on mega topics to preserve performance. Our general recommendation is The MEGATOPIC: public good, or public menace?

3

Thank you for your reply :slight_smile:
I’ve read these post and I understand why megatopics are wrong.

The main “problem” to me is just that the issue course naturally with default Discourse settings, and wouldn’t occur if the limit was 9998 instead of 10000. But I acknowledge that this is a rare issue and a very minor inconvenience. :+1: