QTreeView with QSortFilterProxyModel extremly slow with many (~5000) items

gde23

Hello,

I have a QTreeView that displays some date which is in a class derived from QAbstractItemModel.
When displaying many items (without filter) the view was slow.
Therefore I added

    setUniformRowHeights(true);

and now it is running without unusual delay.

However I need to filter the Items in the view.
Therfore I've added a QSortFilterProxyModel.
However this leads to an extremly slow view (even when filterAcceptsRow() does nothing and just returns true).

Is there some known issue with the QSortFilterProxyModel on large (~5000 items, which is not extemly large) data, or any tricks how I can speed it up?

Christian Ehrlicher

What Os, What Qt version, minimal example please.

gde23

@Christian-Ehrlicher
OS: Debian 10
QtVersion: 5.13.0

I've just tried to generate some minimal example from the editable-treemodel example in the Qt-Examples folder, however it runs perfectly fast there also with the filter.

So it seems the problem is somewhere else.

Ok, I found the problem.
Thanks for demanding a minimal example :)

The reason was, that my columnCount() function is iterative and asking all children for their columnCount to find the max columnCount needed for the view. I will change this to some lazy evaluation then everything should be fine

Christian Ehrlicher

@gde23 said in QTreeView with QSortFilterProxyModel extremly slow with many (~5000) items:

Thanks for demanding a minimal example :)

Thx for trying to create one - sadly a lot of people don't understand the demand for this but this here is a good example why it's needed :)