I have a QGraphicsScene, it contains about 200000 items(this items a added in the beginning of app). Everything works excellent until i have tried to add one more item on the scene, then app hang over ~5 minute for completing this operation.

Callstack operations, which repeat while app hangs

qt_closestLeaf qgraphicsitem_p.h
qt_notclosestLeaf qgraphicsitem_p.h
QAlgorithmsPrivate::qSortHelper<QList<QGraphicsIte m*>::iterator, QGraphicsItem*, bool
(*)(QGraphicsItem const*, QGraphicsItem const*)> qalgorithms.h
qSort<QList<QGraphicsItem*>::iterator, bool (*)(QGraphicsItem const*, QGraphicsItem const*)>
qalgorithms.h
QGraphicsScenePrivate::ensureSortedTopLevelItems qgraphicsscene_p.h
QGraphicsSceneIndex::estimateTopLevelItems qgraphicssceneindex.cpp
QGraphicsScenePrivate::drawItems qgraphicsscene.cpp
QGraphicsView::paintEvent qgraphicsview.cpp
QWidget::event qwidget.cpp

I can't understand what is the problem.
What can I do to solve this problem?

Qt 4.6.2 OS Linux
Sorry for my English.