Slow rendering of a Things create page in MainUI when creating a new Modbus serial slave

[jlikonen]

The problem

When creating a new Modbus serial slave Thing in the MainUI GUI it takes very long time (~4mins) before I can start editing the details for the slave. The image below shows the window when creating a new Modbus serial slave Thing. I have reproduced this problem with two Windows PCs. 2nd openHAB installation is a fresh installation. The problem occurs with different web browsers (Firefix, Opera, MS Edge)

After ~4mins the actual page opens up and you can start editing the details for the slave:

Expected behavior

The page for a new modbus serial slave should open up very quickly.

Steps to reproduce

1. Install Modbus binding
2. In the Settings, click on Things
3. Click on New Thing (blue + at the bottom right-hand corner
4. Choose Modbus Binding
5. Click on Modbus Serial Slave

Your environment

runtimeInfo:
version: 3.2.0
buildString: Release Build
locale: en-US
systemInfo:
configFolder: C:\openHAB\conf
userdataFolder: C:\openHAB\userdata
logFolder: C:\openHAB\userdata\logs
javaVersion: 11.0.13
javaVendor: Azul Systems, Inc.
javaVendorVersion: Zulu11.52+13-CA
osName: Windows 10
osVersion: "10.0"
osArchitecture: amd64
availableProcessors: 16
freeMemory: 216404672
totalMemory: 387973120
bindings:

• modbus
  clientInfo:
  device:
  ios: false
  android: false
  androidChrome: false
  desktop: true
  iphone: false
  ipod: false
  ipad: false
  edge: false
  ie: false
  firefox: true
  macos: false
  windows: true
  cordova: false
  phonegap: false
  electron: false
  nwjs: false
  webView: false
  webview: false
  standalone: false
  os: windows
  pixelRatio: 1
  prefersColorScheme: light
  isSecureContext: false
  locationbarVisible: true
  menubarVisible: true
  navigator:
  cookieEnabled: true
  deviceMemory: N/A
  hardwareConcurrency: 16
  language: en-US
  languages:
  • en-US
  • en
    onLine: true
    platform: Win32
    screen:
    width: 1920
    height: 1200
    colorDepth: 24
    support:
    touch: false
    pointerEvents: true
    observer: true
    passiveListener: true
    gestures: false
    intersectionObserver: true
    themeOptions:
    dark: light
    filled: true
    pageTransitionAnimation: default
    bars: filled
    homeNavbar: default
    homeBackground: default
    expandableCardAnimation: default
    userAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
    Firefox/91.0
    timestamp: 2022-02-06T04:44:47.366Z

Browser console

Browser network traffic

Additional information

[ssalonen]

From the thread https://community.openhab.org/t/abb-3-phase-modbus-electricity-meter-solved/132898/9

Below is a screen shot when I try to add a new slave:

It takes ~4mins before I get the following page:

I’m running openHAB 3.2.0.

I installed OH on another computer (fresh installation) and same problem with this PC.

Just checked with my Android phone and it seems to have same issue. I have used different web browsers (FF, Opera, Edge) so I don’t think it’s browser dependent. Something with the MainUI, I guess.

[Rossko57]

I think a more appropriate title would be 'Slow rendering of a Things create page in MainUI'
How does it behave with other Things from other bindings? e.g. the common Astro or suchlike. Is it just first creation, or edit existing too?

[jlikonen]

Thanks. Yes, I agree that slow rendering is much better wording. I changed the title. I haven't observed this slow rendering with other bindings.

[ghys]

@jlikonen it appears you wrote inside the template comments (<!-- -->) therefore they don't appear above.
Can you figure out using the developer tools' Network tab if the delay is due to an API request taking too long (in which case it's not a problem with the UI) or something else?

[jlikonen]

Sorry, but it's not quite clear to me what you mean. I can't see a Network tab under the Developer Tools.

[ssalonen]

I believe the comment was referring to browser developer tools https://www.freecodecamp.org/news/chrome-devtools-network-tab-tricks/

[jlikonen]

OK, now I understand. I opened up the developer tools in Chrome. While OH was rendering the page I took a screen copy of the network tab.

After rendering had finished the screen copy is:

You can see that time for modbus:serial is 4.7 min which is roughly the time for rendering. I'm not sure whether these screen copies are useful or not, though.