[PyQt] Performance problems with QSortFilterProxyModel

[Steve Borho]

Hello,

The TortoiseHg project is currently porting all of our PyGTK apps to
PyQt, This has been going pretty well so far, but I've hit a snag with
our file status browser.

I have a simple QAbstractTableModel (4 columns) being displayed in a
QTreeView.  After connecting a QSortFilterProxyModel between the tree
view and the data model, reloading the model became very expensive for
moderately sized data sets.  After calling setSourceModel() with a
model of 555 rows, I counted over 3 million calls to the model data()
method, which takes about 15 seconds.

I googled around and found some complaints that
resizeColumnToContents() was expensive when the sort filter was in
use, and I confirmed that in our case  (using simple print profiling).
 However, removing the resize statements only moves the performance
hit till later on.  I can only guess the sort model is waiting for
it's first access to perform the initial sort.

I'm pretty sure I could implement the simple sorting and filtering we
need in our data model, but before I do I thought I'd ask here if
there was some common problem that could cause this performance hit.
This kind of smells like the kind of problem caused by not disabling a
signal while you do certain operations.

Cheers

--
Steve Borho