Ungrouping a large group is very slow

[Oliver Sander]

I have a drawing obtained by converting an eps using pstoedit -f plot-svg. The resulting svg consists of a single group with about 19000 lines and polygon. Ungrouping this group to edit the drawing takes several minutes on my 1.7GHz notebook
and consumes about 250MB of main memory. This seems like a lot to me, even for 19000 elements.

This happens with inkscape-0.47pre1 on a Debian Squeeze machine.

[Pablo Trabajos (pajarico)]

Confirmed that it takes several minutes. But I can't tell if this is due a bad piece of code. A developer will have to look into this.

[Dave Eccleston (david-c-eccleston)]

This issue is marked low priority, but it's a BIG problem. The files I work with come with a LOT of grouping. Initially, I need to ungroup everything. But each ungroup takes 5-7 minutes, and I have to ungroup many times. It took me an hour to ungroup all the groups in the attached file.

I see this bug has been open since 2009, any chance it could be looked at? It affects almost every project I work on.

[jazzynico (jazzynico)]

Reproduced on Windows XP, Inkscape trunk rev. 14998.
Ungrouping the object from the file attached comment #1 takes about 1 minute with an i5-3470@3.2GHz CPU. Still quite slow anyways.
Changing Importance to Medium to be consistent with other performance related reports.

[Albert (sapristi)]

The same issue persists in Ubuntu 16.04 with Inkscape 0.91.

[Randall O'Reilly (rcoreilly)]

Same issue on Mac 10.12 with Inkscape 0.91. Very disruptive bug!

[Szilárd Páll (sin-pecado)]

Same here, still a big issue, even with 0.92 on a high-end desktop CPU even with a few hundred objects! Moving around groups can also be painfully slow.

[Hachmann (marenhachmann)]

It's slower for me in 0.92.1 than in 0.91 (see example in forum: http://forum.inkscapecommunity.com/index.php?topic=612.msg4399;topicseen#new )

[Patrick Bradley (patrick-bradley)]

I can confirm that this is still a problem as of 0.92.1. I got access to a machine running 14.04 and can also confirm that this is not a problem in 0.48.4 r9939. Unfortunately getting 0.48 installed on 16.04 seems to be beyond me (won't compile even though 'configure' finishes with no errors), so this is not a good work-around.

[Patrick Bradley (patrick-bradley)]

Ugh, sorry, I meant to write Ubuntu 14.04 and Ubuntu 16.04, respectively!

[Reto (norfootek)]

Could this be related to https://bugs.launchpad.net/inkscape/+bug/1431274 ?
Note that simply closing the Objects dialog does not help. You have to restart Inkscape.

[mbiochem (mbiochem)]

I have the same problem that is very severe.
The same files are opened easily and ungrouped easily in version 0.48.

[Michael Duffy (mduffor-q)]

Can this bug pleeeeeease be addressed by the dev team. It is costing me a lot of productivity, since my workflow is interrupted by multi-minute grouping and ungrouping. This should really not be an issue if the operation is coded properly; it should just be a rearrangement of existing internal structures without any new memory allocation, object creation, or extra refreshing of the scene state.

[Hachmann (marenhachmann)]

Workaround for those who suffer productivity issues:

Use the 'Deep Ungroup' extension you can find at Extensions > Arrange.
It only takes a split second where the normal ungroup takes minutes.

[Hadrien Mary (hadim)]

I am having the same issue with Ubuntu 18.04 and Inkscape 0.92 from trunk ppa. Could this be adressed or at least commented by a dev? Thank you !

[Finog (finog)]

I also have this issue with Inkscape 0.92.3 (2405546, 2018-03-11). The "Deep Ungroup" extension was a good workaround for me. Perhaps Inkscape performs intermediate rendering during the ungroup operation?

[Hachmann (marenhachmann)]

Oh, I think I need to copy this to gitlab, someone is working on removing intermediate rendering for Boolean operations there: https://gitlab.com/inkscape/inkscape/merge_requests/438#note_123456665

[Diederik van Lierop (mail-diedenrezi)]

The part of this bug that was related to the objects panel being open, has been fixed. The object panel now handles large documents much easier, without bogging down Inkscape. To test if the object panel is the culprit, you have to close the objects panel and restart Inkscape.

The objects panel was really a pain, as on some of my documents it would take 24h to ungroup when the documents panel was open.

Ungrouping a group of 20k - 40k will still take on the order of a minute or so, but this is not completely unreasonable IMHO. For sure it can be improved furter, but this is not a blocker. (hint: Selection::_emitModified(guint flags) is only being called on idle; why not do the same for _emitChanged? would this work?)