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No content in Gantt Charts in Apex 20.2

Steve Vlp
Steve Vlp Member Posts: 5 Green Ribbon

We have recently upgraded our apex environment from 18.2 to 20.2.

Is it possible there's a bug with the Gantt charts? There's no content in the charts.

Example in Sample charts app at apex.oracle.com

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Answers

  • Hilary Farrell-Oracle
    Hilary Farrell-Oracle Software Development Senior Manager Member Posts: 2,409 Employee

    Hi user1101665,

    Can you please provide more information, to better understand the behaviour you're seeing?

    1. When you upgraded your instance to APEX 20.2, did you install a new version of the Sample Charts app, or are you using the version you had previously installed with APEX 18.2?
    2. When you say 'there no content in the charts' - do you mean that the charts are rendering but you're seeing no data points rendered on the chart?

    My suspicion is that you're running the older version of the Sample Charts app. We don't upgrade the Sample apps, so it's necessary to completely remove the old version (and it's supporting objects), before installing the new version available in APEX 20.2. If you did not do that, then the chances are that the dataset your Gantt chart is trying to render is for a few years ago, but the viewport of the Gantt chart is only attempting to render the last few months. So try removing the app entirely & reinstall. If you're still experiencing issues, please let me know if any errors are being reported in the browser console.

    Regards,

    Hilary

  • Steve Vlp
    Steve Vlp Member Posts: 5 Green Ribbon

    Thanks for responding. I'm not using the Sample Charts - it's an application I've made a few months ago.

    By no content I meant: chart is rendered but no data points and header

    To make it more awkward: when I duplicate my region, the first chart stays blank - the other chart has points...


  • Hilary Farrell-Oracle
    Hilary Farrell-Oracle Software Development Senior Manager Member Posts: 2,409 Employee

    Hi user1101665,

    Hmm interesting ok - can you provide access to a reproducible testcase on apex.oracle.com, so I can take a look? One thing that springs to mind when I view that screenshot is to check whether you've defined a Static ID on the chart region - and if you duplicated the region, did you change the Static ID of the second region, to ensure it's different? This is purely a guess, based on the screenshot. So if that's not relevant in this instance, the reproducible testcase on apex.oracle.com would definitely help.

    Regards,

    Hilary

  • Steve Vlp
    Steve Vlp Member Posts: 5 Green Ribbon

    Hmm, I really don't get it. I have more luck in Firefox (90% it shows both) - screenshot was in Chrome.

    There are no static ID's for the regions.

    I've made a testcase at: https://apex.oracle.com/pls/apex/sdkspace/r/gantt-chart1/home . Everything does work on the oracle domain.. (with a few CSS issues (transparancy of a graph))

    Thanks!

    Steve

  • Hilary Farrell-Oracle
    Hilary Farrell-Oracle Software Development Senior Manager Member Posts: 2,409 Employee

    Hi Steve,

    Thanks for providing the testcase. I've tried it using Firefox 86.0 and Chrome 88 on my laptop, and Chrome 88 on my Android mobile device, and all render without issue. I'm also not seeing any issues with transparency, which makes things a little tricky to debug when I can't reproduce what you're seeing.

    As you recently upgraded, can you confirm that your instance images were also updated? My assumption is they were, but better to ask & double-check, just in case that step was missed.

    It's worth switching on Debug in your app on your own instance, and check the browser console for any errors that may be reported. If you're seeing any errors reported, please let me know & I'll try to assist further.

    Regards,

    Hilary

  • Steve Vlp
    Steve Vlp Member Posts: 5 Green Ribbon

    I found the solution (or maybe workaround)! On the chart region - Attributes: I've set Animation "On Display: None" and "On Data Change: None" (default was "Automatic" for both attributes).

    I've found it because there was sometimes a transparancy (opacity < 1) in the charts. Example: <g opacity="0.0023708160000000004" ...>. That's why I never saw my values in the charts.

    In any case: thanks for helping me!!

    User_1IR7D
  • user3867057
    user3867057 Member Posts: 3 Red Ribbon

    Sorry to revive an old Thread, but I have the exact same issue. I'm running a local instance of Oracle APEX 22.1.0.

    The solution for me is the same work-around posted - in Gantt Chart attributes, "On Display" must be set to None.

    Interestingly, if I install the Sample Charts app, the Gantt chart (which works) comes with that particular setting. If I modify it to "On Display" -> Auto, then the chart also fails to show any points or content.

    Something else that I noticed, is that "On Display" -> Auto will work if Debugging is set to Level9 (full trace), or if (on Chrome dev settings) you throttle down the speed of the network to Slow or Fast 3G. It appears to me to be an issue with the timing of the JavaScript execution in the page.

    Unfortunately, when you create a new Chart region from scratch and set it to Gantt type, the default option for "On Display" is Auto, which causes the bug in this thread.

    Is there some sort of way to reach out to the Apex dev team ?

  • Hilary Farrell-Oracle
    Hilary Farrell-Oracle Software Development Senior Manager Member Posts: 2,409 Employee

    Hi user3867057,

    Is there some sort of way to reach out to the Apex dev team ?

    Yes indeed - I'm on the APEX development team, and myself and a number of my team mates regularly review and respond to posts on the forum.

    Thanks for your follow-up to this thread - I know it's an old one, and generally not advisable to update an old thread, but this does help for context. This is a bit of a troubling one for me as to-date I've not been able to reproduce this reported behaviour. If the default animation setting of 'On Display' was a general issue, I'd have expected more feedback on this over the years, and I'd have changed the default to something other than 'Auto' and raised this issue with the JET team. Unfortunately, this doesn't appear to be a general issue - but clearly it's negatively impacting you, which isn't good. Can I ask whether you've tried to reproduce this issue on apex.oracle.com? I'm curious to know whether the issue is only reproducing on your local instance.

    Something else that I noticed, is that "On Display" -> Auto will work if Debugging is set to Level9 (full trace), or if (on Chrome dev settings) you throttle down the speed of the network to Slow or Fast 3G. It appears to me to be an issue with the timing of the JavaScript execution in the page.

    Do you experience issues with other components rendering in your app, or is it literally just the Gantt chart?

    Regards,

    Hilary

  • user3867057
    user3867057 Member Posts: 3 Red Ribbon

    Hi Hillary,

    Thank you for your very promptly response. I was not aware that you were part of the APEX dev team.

    I did create a very tiny sample application to demonstrate the Gantt chart bug in apex.oracle.com. The issue does not appear to be replicable there. If I export the same application from apex.oracle.com and install it in my local environment, then the issue surfaces - same application, no changes. You can access the link to the test page here https://apex.oracle.com/pls/apex/r/spinit/gantt-test/gantt-test



    What I did notice though, is that through apex.oracle.com I get more network latency. If the issue really has to do with that, then that could explain why I don't see the problem in apex.oracle.com, but do experience it in my local environment with lower latency. However, if I create (in Google chrome) a custom Throttling profile to introduce 320 ms of latency, then the Gantt chart suddenly works on my local environment.

    I will leave a few screenshots to illustrate

    App in apex.oracle.com, no throttling - natural latency slightly above 300ms between page load and xhr POST request for JSON data for the chat

    App in local env, no throttling - natural latency below 300ms, between page load and xhr POST request for JSON data

    App in local env, with 320 ms induced throttling (with Chrome Devtools, custom Throttling profile), to simulate apex.oracle.com env, the graph now works

    One thing that I did notice, is that our local environment is running without HTTPs at the moment. The console log warns about a service worker not possible in these conditions. Due to that, there is a difference in the network calls between apex.oracle.com and my local environment, where one last call isn't performed - the one with type fetch. Perhaps this could be a problem ?

  • Steve Vlp
    Steve Vlp Member Posts: 5 Green Ribbon

    I've had this issue with our local database in my company, with HTTPS.