Update check for installed VS Code Extensions is making time to usable GUI very slow

[slhultgren]

Bug Description:

During Theia startup and initialization of the VSXExtensionModel, each vs code extension will be checked against open-vsx.org for update.
The usable GUI is not shown until these update checks has completed.

If you are on a slow network or have a lot of extensions installed (since open-vsx is also rate limited) this will take a long time
With 75 VS Code extensions installed and running Theia in the browser I get this timing of Refresh to GUI: between 50 and 90 seconds.

If I remove this line https://github.com/eclipse-theia/theia/blob/master/packages/vsx-registry/src/browser/vsx-extensions-model.ts#L67

And try the same thing, still with 75 vs code extensions installed, I get Refresh to GUI at a pretty stable 16 seconds for "theia build --mode development"

IMO This update check should be triggered as a background task after the main GUI has been presented.

Steps to Reproduce:

1. Install a fair number of VS Code extensions
2. Refresh/restart the Theia instance
3. Observe that the spinning wheel does not disappear until all the queries against open-vsx has resolved (using network tab in debug tools)

Additional Information

• Operating System: Linux
• Theia Version: 1.10.0

[vince-fugnitto]

@slhultgren thank you for reporting the issue, do you have any suggestions on how to improve the performance without a loss of functionality? The initInstalled is used to populate the view (installed and builtins), its possible that this should not be awaited so it does not block the application.

[slhultgren]

@vince-fugnitto I need to dig deeper into the updateInstalled() to give a good answer to why we thought we needed to await this function initially.
For now I have not noticed anything obvious by just removing it, or even putting the entire try { update } catch {} block in a setTimeout 60 seconds also seems to do the trick.

I did try just removing the await part but that alone does not solve the issue since it seems the queries to open-vsx are still awaited before presenting the GUI for some reason. I'm hoping to have some time in the coming days to maybe dig into this a bit more.