Slow/Unresponsive UI starting Jambi 6.4.2

[ygorodnitsky]

Using QT 6.4.1 We experienced signficant UI performance degradation starting with Jambi 6.4.2. As if the UI thread is being paced/overwhelmed.
I created a prototype project. This is an intentionally large table with moderately quick updates. It loads in 6.4.1 -- The window may have some responsiveness issue when resizing, but otherwise scrolling is smooth and easy. In our application we have a different window qml class, so resizing isn't handled by the OS, so it's not an issue, for this example scrolling and general UI responsiveness is the main problem.
BigTableProblem.zip

With 6.4.2 the app hangs and doesn't load to even try to do anything.

[mchistovib]

@omix please have a look

[omix]

I've foud the reason for this behaviour. Latest QtJambi release has native QModelIndex type. Before it was lightweight. The native implementation of QModelIndex needs a dependency link to the model because Java object has to be invalid when model is deleted. This link is causing high computational effort because of a hash map contains check. This is only recognizable for huge numbers of objects, which you have. I will fix this for the next release.