Re: GtkListStore

[Linus Walleij <triad df lth se>]

On Thu, 12 Jun 2003, Petnuch, Michael wrote:

> I am having performance problems with GtkListStore.  I am adding around say
> 500 rows all of which are being updated constantly.  I do:

I bet this error is the same that I was helped in just a few days ago. I
submitted a documentation bug for it:

http://bugzilla.gnome.org/show_bug.cgi?id=114657

-----------------

Document sorting behaviour for gtk_tree_sortable_set_sort_column_id ()

Information from the gtk-list gives at hand that invoking this function
under certain circumstances has some undesired side effects. I propose
adding the following text to the manual section on GtkSortable or in the
FAQ:

Calling gtk_tree_sortable_set_sort_column_id() on a certain GtkTreeStore
or GtkListStore will turn on sorting for this list store. This will slow
down performance on subsequent data additions from O(n) to O(n^2). There
is no way to turn sorting off again. If you repeatedly add several (say
thousands) of rows to a tree or list store, this will cause a noticable
delay.

Therefore, if you desire large, sorted lists and trees, the procedure to
follow when filling the store anew is:

1. Create a new list store with gtk_list_store_new()
2. Replace it for the one currently connected to your view with
gtk_tree_view_set_model()
3. Invoke g_object_unref() on the old store and destroy it.
4. Fill the new store with some thousand entries.
5. Turn sorting back on using gtk_tree_sortable_set_sort_column_id()

--------------------

That said, I can think up algorithms that should be able to do addition in
O(n log n) or so, but probably GTK should eventually be improved with a
fuction like the freeze() of CList that can temporarily turn off sorting
and then turn it back on again after adding rows. I don't know how that
matches with the GTK architecture though.

Linus