Bug 196 – History window is slow to populate if Undo stack is large.

••• Introduction •••
••• Keywords •••

Audacity 3.0.3 development began 19th April 2021

Audacity Bugzilla

Bug 196 - History window is slow to populate if Undo stack is large.


Summary:	History window is slow to populate if Undo stack is large.

Status:	RESOLVED FIXED

Product:	Audacity
Classification:	Unclassified
Component:	Application Core
Version:	unspecified
Hardware:	Per OS All

Importance:	P3 Repeatable
Assigned To:	Default Assignee for New Bugs

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2010-08-04 20:53 UTC by Vaughan Johnson
Modified:	2018-08-20 11:45 UTC (History)
CC List:	2 users (show)

See Also:
Steps To Reproduce:
Release Note:
First Git SHA:
Group:	---
Workaround:
Closed:	2018-08-20 00:00:00

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.

Description Vaughan Johnson 2010-08-04 20:53:04 UTC

This bug is split out from discussion on bug 113.

Vaughan:
> Looked into history window slowness. It was doing unnecessary repetitive
> clearing and filling the list, so if it's still slow, then we will have real
> evidence that UndoManager is slow at scanning the stack. 

Gale:
When I tried (Comment 5) to import 50 WAVs via OD, History took 10 seconds to
load (while the waveforms were still being drawn). That is still true now. But 
when I now imported 30 MP3s mostly 3 minutes long, accessing History (after the
imports had completed of course) took 3 minutes. During most of this time
History was empty and not responding. Loading history took 2.5 minutes when
repeating the test on a freshly booted machine.

Comment 1 Vaughan Johnson 2010-08-06 20:31:39 UTC

Commit 10583: Calculate space usage for a state frame (UndoStackElem) in UndoManager::PushState, i.e., only when the UndoStackElem is created, rather than for all UndoStackElem's every time we open History Window. This should considerably speed up opening History Window when the stack is large (many frames and/or lots of data), and fix bug 196.

Comment 2 Gale Andrews 2010-08-11 23:59:01 UTC

The fix makes a huge difference on Windows - access to history is now near immediate. Also access is immediate now on Mac and Ubuntu (though it seems it wasn't a problem on Mac before the fix). Thanks for this.