Major performance issue on GUI side of ParaView
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
In the attached archive MKWReader.tar.gz a dummy small reader plug-in to highlight the problem of performance we meet in our reader plug-in. After investigation, the problem of performance we meet is client side when the number of entries in a tree is ~4000 elements (instances of linked pqTreeWidgetItemObject).
A brief description of this small Plugin: it reads a dummy file with *.mkw extension containing an unsigned integer; this file (in the Doc directory) is called OneIntegerFile.mkw.
The example reader generates a server side unstructured grid containing just one cell (to show that the server side is particularly light ) and a field array called "FakeField" containing a single component, the unique value of the field is specified on the client side. On the client side, there is a list of <nb_of_value_in_mkw_file> pqTreeWidgetItemObject objects in the tree view "Select a value for your field on VTK_QUAD".
THE PROBLEM: the ellapsed time needed to have a rendering is quite big (the moment between we click on "Apply" and the time to have the rendering of the single cell):
1000 items in browser : ~3 s 2000 items in browser : ~12 s 4000 items in browser : ~44 s
Another problem is the reactivity of the tree with 4000 items. Each click in the tree takes 1 second. We remark that all the time is spent on the Client-side, more especially in the GUI part of paraview.
We need thousands of items in our real reader plug-in, consequently such amount of time is blocking for us.