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Post by takafumi ohtake »

Hi Bryntum support,

When the resource histogram is displayed with a long span like many years, the browser freezes.
This issue is reproduced on https://bryntum.com/products/gantt/examples/resourcehistogram/
If the calendar is complicated, this issue will be even worse.

How to reproduce

  1. Add calendar intervals (optional.)

    gantt.project.calendars[0].intervals.add([
        {
            "recurrentStartDate": "every weekday at 12:00",
            "recurrentEndDate": "every weekday at 13:00",
            "isWorking": false
        },
        {
            "recurrentStartDate": "every weekday at 17:00",
            "recurrentEndDate": "every weekday at 08:00",
            "isWorking": false
        }
    ]);
    
  2. Zoom out the timeline.

    gantt.zoomTo(0);
    
  3. Shift the timespan

    gantt.shiftNext();
    

Expected
Zoom and shift can be done without having the browser freeze.

Observed
The browser freezes on the step 2 and 3.


Post by tasnim »

Thanks for your detailed report. Reproduced! We'll investigate it. Here is the ticket https://github.com/bryntum/support/issues/5671

Good Luck :),
Tasnim


Post by takafumi ohtake »

Hi Bryntum support,

This performance issue sometimes makes our app crash.
Could you please prioritize this issue more?


Post by alex.l »

Hi,

I will let our product management know that and try to push it! Thank you for your patience!

All the best,
Alex


Post by takafumi ohtake »

Hi Alex,

Thank you for your reply.

I want to add additional information.
When there're many tasks to render in the histogram, this issue is more frequent and severe.
I tested it with 500 tasks over 1000 days and four resources. The app often crashes in long-span view such as quarterly and monthly.
I hope the histogram component work without performance issues (especially without a crash) in such condition.


Post by alex.l »

Thank you for the information! I notified product management about your request and they promised to put into nearest releases, not sure about nearest one, but also possible.

All the best,
Alex


Post by takafumi ohtake »

Dear Alex,

I wanted to bring to your attention that one of our large customers has also reported this issue.
As this problem is critical for us, I was wondering if you could provide us with an estimated release date for the fix.
Thank you for your time and attention to this matter.

Regards,
Takafumi


Post by arcady »

Hello,
I've checked the ticket and it has this call:

gantt.zoomTo(0);

Doing the call actually means that you request the histogram to collect allocation data for a 125 years time range.
Even though most of the time range is not allocated to tasks max allocation time still has to be collected.

The quickest and the most reasonable workaround for this is not doing this call at all.
There are special configs limiting zooming:
https://www.bryntum.com/products/gantt/docs/api/Gantt/view/Gantt#config-minZoomLevel
https://www.bryntum.com/products/gantt/docs/api/Gantt/view/Gantt#config-maxZoomLevel

And I think specifying minZoomLevel makes perfect sense. When you request to collect data for a huge time range you are expected to have a super fast machine with a lot of memory that can handle that. And I don't think all users have such machines so limiting zoom is the way to go.

Other than that I don't see an easy way for fixing that. We can try refactoring calendars (which cache filling causes that freezing) but that will be a really time consuming task I'm afraid.


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