[#73847] Improve backlogs "Show x more items" frontend performance

[dombesz]

Ticket

https://community.openproject.org/wp/73847

What are you trying to accomplish?

Improve the performance of the "Show X more items" link.

What approach did you choose and why?

• Remove the use of StoryController as outlets in the BacklogsController. Having a large number of stories used as outlet gives a high performance hit to the rendering. It takes up more than 2/3rd of the loading time.
• Implement the same functionality only inside the StoryController.

In my local environment using 1000 work packages, the processing time is reduced from 24 seconds to 1.7 seconds..

Screenshots

Before:

After

Merge checklist

• Added/updated tests
• Added/updated documentation in Lookbook (patterns, previews, etc)
• Tested major browsers (Chrome, Firefox, Edge, ...)

[github-actions]

Caution

The provided work package version does not match the core version

Details:

• Work package URL: https://community.openproject.org/wp/73847
• Work package version: not set
• Core version: 17.3.0

Please make sure that:

• The work package version OR your pull request target branch is correct

[myabc]

This looks good code-wise. I haven't yet tested locally.

[ulferts]

Change looks good and solid. On my machine, with 1000 work packages rendered on clicking the loading button, the time spent in the front end drops from 6 seconds to 300ms which is quite substantial.

Regarding the architecture I wonder if using a custom event wouldn't be cleaner. The BacklogController would be remain responsible for listening in on turbo:visit and for determining the id of the displayed work package from the url. It could then send a custom event the StoryControllers listen to. But in the end, it is not really changing the number of listeners so I am undecided.

The main bottleneck now seems to be the frontend rendering. Out of the ~3 seconds it takes the backend to answer when the loading button is clicked, ~2.99 s is spent in the view. The data itself is loaded quickly although that could also be because of the simplified test data i created.