Developer Blog

So I was adding a huge list of abbreviations (over 15K) to Breevy about a week ago and noticed that it took *way* too long for the GtkListStore to be populated. Way too long, as in over a minute on a 3GHz P4.

After a bit of investigating I finally figured out that the bottleneck was the fact that the list store was a sorted store, and that it appeared GTK+ was resorting the store after each row insertion. I turned off sorting, and populating the store was almost instant.

So first I worked around this issue by setting the sort column ID for the list store to GTK_TREE_SORTABLE_UNSORTED_SORT_COLUMN_ID before populating. This disabled any sorting during the insertions. Then, after the insertions, I set the sort column ID back to what it was before, triggering a final sort of all of the inserted rows. I knew this was a bit hackish, but it worked.

But then I found out how to do it The Right Way: by calling the gtk_list_store_insert_with_values() function. Basically, you should use this instead of a gtk_list_store_append() and gtk_list_store_set() when inserting rows into a sorted store because these two latter functions basically tell the list store to resort itself after each new row is inserted (i.e., number of sorts == number of rows inserted)... something that's not necessary, and something that takes a heckuva long time.

The speedup I experienced using the insert_with_values() function was absolutely massive. Thanks to the folks on #gtk+ on irc.gnome.org for pointing the function out to me.