Forum Pages becomes very sluggish to scroll

Half a day ago, I had no problem. Then, I reinstalled my computer and haven’t yet installed a few of my fav extensions (that do not auto-sync) on the browser. So I am not sure if it was always like this.

Right now, I am having a hard time browsing the forum. Loading speed is pretty well as usual, but scrolling is a pain.

All other, including other MongoDB sites, are lightning fast but here I am experiencing maybe a 10 times slower scrolling. (again not the loading)

If you had a change today, please revert it back and fix whatever you have added. Else you need a thorough inspection of Forums.

Hi @Yilmaz_Durmaz I am not experiencing any issues with the forums and scrolling currently. I have been active on the forums throughout the day (US time) without issue. Are you still having problems?

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I have restarted the browser and pc. I can’t remember how fast it was before. At least, it is now much faster and more browsable without pain.

But still a bit sluggish compared to SO for example. Scrolling SO homepage a few times longer than here takes half the time.

I can’t say what was the cause for slugging, yet I might add this gave me an another sight on the design. It may still be sluggish on low-core slow-memory machines (mine is 10y old but 8GB with 8-core, so still fast) as not all of us have high resources. It is worth having an optimizing look at the Forum’s codes.

Hi @Yilmaz_Durmaz,

Thank you for your feedback, as always!

We have a few monitoring solutions in place and I don’t see any specific alerts or other reports in the same time period. Some more localised issues can be difficult to track down, but we’re definitely interested in trying to improve the user experience.

Can you share more details including:

  • browser version
  • O/S version
  • example urls that were notably slow
  • any observations on the slowness – was this more typical for initial page load, loading more posts, etc

Are you still seeing slowness as compared to before reinstalling your computer?

One common slowdown for a new O/S install (particularly with many existing files) is O/S indexing files for search (eg Search indexing for Windows or Spotlight Search for macOS). The initial O/S indexing build can take many hours depending on the number of files to index and system resources.

Other possible reason for slowdowns could include:

  • local network or ISP
  • browser plugins such as ad blockers
  • busier web traffic at the time of your site access
  • repopulating browser cache for a fresh install

Our community platforms team has some ongoing projects to improve user experience including performance and design, but we’re still a relatively small team compared to our backlog of tasks :).

Regards,
Stennie

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Hi @Stennie_X

  • browser version:
    • MS Edge
  • O/S version:
    • Windows 10 21H2
  • example urls that were notably slow:
  • any observations on the slowness – was this more typical for initial page load, loading more posts, etc
    • the following link is a screencast video of comparison the to SO page as of now.
    • mongodb forums are slow.webm - Google Drive
    • SO page has about 5 times longer content and scrolling is fast.
    • Even with shorter content, scrolling the Forum’s homepage is relatively slow and the scroll bar lags behind the mouse.

I really can’t remember (fish memory) how was it before the system was re-installed. But after the installation, it sure was like playing a 60fps action game at 3-5 fps. And I can’t tell either what has changed in one reboot but the comparison was the same: the Forum was slow yet other pages were functioning normally.

PS: the link opens a preview video at a reduced size of 360p. details are not seen much but the scrolling difference is clear.

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@Stennie_X I had another test about the slow experience.

I had to reinstall (again) my system for an account sync problem; easier than trying to fix :sweat_smile:

This time I had no extensions installed. Yet again, other sites were fine while the Forum was still slow.

After a few minutes, I noticed the pages were partly fast. Then I opened the browser’s task manager and saw a high CPU usage.

The usual workings of web pages are to “load and keep” on page load or after scroll, but it seems it is like “load then forget and reload” for every scroll action.

Although it was initially worse just like I described in the first post, it gradually become faster to scroll.

This new video shows an increase in CPU usage while scrolling: mongodb forums high cpu usage.webm - Google Drive

These high levels are the culprit behind. It lowers the browsing experience on mid-to-low-end devices.

I hope web devs will find the actual code causing this and fix it.

I just created similar topic. It’s because they’re using a 5000x10000px PNG in the background :joy: Looks like these backend guys have no idea how the frontend works.

Wow, I had never imagined this would be the culprit.

I have identified at least one of these image files: dark-bg.png (4098×10726) (mdb-community.s3.amazonaws.com)

In a 10s page performance test, almost 50% was spent in the page painting stage. I have added it to my blocked URL list and cleared the cache for the forums. now pages flow blazing fast compared to the previous state.

Files with 500kb sizes are generally just big in disk size, but this guy is in png format and can occupy a lot of CPU resources to display. and the forum pages try to refresh for every scroll event.

@Stennie_X, can you please warn the responsible team? (by the way, did the forums disable the tagging/viewing MongoDB team members?)

Unfortunately Stennie is no longer with MongoDB. It sounds like he’s taking time to travel, be with family/friends and basically just enjoy life, before starting up his next career adventure. He’ll definitely be missed around these parts.

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