View Issue Details

IDCategoryLast Update
0007274bugs2017-04-23 23:00
ReportertimbyrAssigned Totimbyr 
Status resolvedResolutionfixed 
Product Version5.8 
Fixed in Version5.X git (version in description) 
Summary0007274: Loading Session with selected regions can take a really long time
DescriptionTested with version 5.8.76 + logging/tracing patches

In a moderate size session with several hundred regions if the Session is saved with many selected regions then the Session can take a very long time to load
compared to without a region selection (5 seconds vs 60+ seconds) depending on the number of regions selected.

As part of Editor::first_idle region/views that are selected are added to the region selection one region at a time calling Selection::add. Selection::add emits a signal that is connected to Editor::region_selection_changed that calls Editor::sensitize_the_right_region_actions which itself is > O(n2) as it iterates through the RegionSelection calling Region::at_natural_position which calls Session::find_whole_file_parent which also iterates through all the regions in the Session AFAICT. So the whole process ends up being > O(n3).

It is also an issue for normal region selection in that Editor::sensitize_the_right_region_actions is called, but at least only once.

It is probably just easier to understand by looking at log/trace file I've attached that can be viewed with chrome/ium://tracing
TagsNo tags attached.



2017-03-07 11:51


Ardour.trace.load-session-with-region-selection.json.tar.xz (3,049,596 bytes)


2017-04-02 17:37

administrator   ~0019582

should be much improved since f31e938da0


2017-04-02 22:28

developer   ~0019584

I can't find a commit with that id in the master branch. Are you are sure that is correct? or is it located somewhere else?


2017-04-02 22:34

administrator   ~0019585

sorry, had not rebased or pushed. it is 54bab5153f1cb


2017-04-03 00:59

developer   ~0019589

Testing with a build of 54bab5153 and the load time is now much reduced.

I did notice though that after selecting a region and deleting it then undoing the action will no longer result in the region begin re/selected.


2017-04-20 12:10

developer   ~0019615

There seems to be a related issue that I can reproduce in 5.8.236 and 5.8.533.

Steps to reproduce:

1. Create or open a Session with many regions. Several hundred should make the issue noticable.
2. Select all the regions in the Session.
3. Split a region using split tool or 's' key.
4. Undo the Split.

Result: Depending on the amount of Regions in the Session the application will freeze for a period of time, several seconds to perhaps minutes depending on number of Regions selected.

I've attached another trace/log that makes it apparent it is a similar issue with regions being added individually to the selection.


2017-04-20 12:10


Ardour-5.8.533-split-region-with-selection-undo.json.gz (1,173,315 bytes)


2017-04-23 11:23


7274-fix-freeze-on-undo.patch (936 bytes)
diff --git a/gtk2_ardour/ b/gtk2_ardour/
index 1a95f8c..72b8f0e 100644
--- a/gtk2_ardour/
+++ b/gtk2_ardour/
@@ -1531,6 +1531,8 @@ Selection::set_state (XMLNode const & node, int)
 	clear_tracks ();
 	clear_markers ();
+	RegionSelection selected_regions;
 	PBD::ID id;
 	XMLNodeList children = node.children ();
 	for (XMLNodeList::const_iterator i = children.begin(); i != children.end(); ++i) {
@@ -1555,7 +1557,7 @@ Selection::set_state (XMLNode const & node, int)
 			editor->get_regionviews_by_id (id, rs);
 			if (!rs.empty ()) {
-				add (rs);
+				selected_regions.insert (selected_regions.end(), rs.begin(), rs.end());
 			} else {
 				  regionviews haven't been constructed - stash the region IDs
@@ -1715,6 +1717,9 @@ Selection::set_state (XMLNode const & node, int)
+	// now add regions to selection at once
+	add (selected_regions);
 	return 0;


2017-04-23 11:29

developer   ~0019625

I've attached a patch that should fix the issue mentioned in the last comment.

It feels like more of a workaround as there is still the issues with Editor::sensitize_the_right_region_actions


2017-04-23 11:31

developer   ~0019626

I can commit the fix if there is some agreement that this is an acceptable solution for now.


2017-04-23 17:04

administrator   ~0019629

patch looks ideal to me. it won't even conflict with the "selection2" branch. please commit it.


2017-04-23 17:05

administrator   ~0019630

that said, there is another approach ... but i think they are 6 of 1, half a dozen of the other; put a PresentationInfo::ChangeSuspender in scope while the regions are added to the selection.


2017-04-23 22:59

developer   ~0019635

OK, well I've pushed the patch to master as 1b2bc203a or nightly build >= 5.8.574

I'm marking this issue as resolved.

Issue History

Date Modified Username Field Change
2017-03-07 11:51 timbyr New Issue
2017-03-07 11:51 timbyr File Added: Ardour.trace.load-session-with-region-selection.json.tar.xz
2017-04-02 17:37 paul Note Added: 0019582
2017-04-02 22:28 timbyr Note Added: 0019584
2017-04-02 22:34 paul Note Added: 0019585
2017-04-03 00:59 timbyr Note Added: 0019589
2017-04-20 12:10 timbyr Note Added: 0019615
2017-04-20 12:10 timbyr File Added: Ardour-5.8.533-split-region-with-selection-undo.json.gz
2017-04-23 11:23 timbyr File Added: 7274-fix-freeze-on-undo.patch
2017-04-23 11:29 timbyr Note Added: 0019625
2017-04-23 11:31 timbyr Note Added: 0019626
2017-04-23 17:04 paul Note Added: 0019629
2017-04-23 17:05 paul Note Added: 0019630
2017-04-23 22:59 timbyr Note Added: 0019635
2017-04-23 23:00 timbyr Status new => resolved
2017-04-23 23:00 timbyr Fixed in Version => 5.X git (version in description)
2017-04-23 23:00 timbyr Resolution open => fixed
2017-04-23 23:00 timbyr Assigned To => timbyr