Bug 520577 - Navigating in thumbnails/preview uses 100% of main thread for 10-15 seconds on each selection change
Summary: Navigating in thumbnails/preview uses 100% of main thread for 10-15 seconds o...
Status: RESOLVED FIXED
Alias: None
Product: digikam
Classification: Applications
Component: Albums-ItemsGroup (other bugs)
Version First Reported In: 9.0.0
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: Digikam Developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2026-05-23 20:23 UTC by Saveliy Vasilev
Modified: 2026-05-24 03:55 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In: 9.1.0
Sentry Crash Report:


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Description Saveliy Vasilev 2026-05-23 20:23:03 UTC
DESCRIPTION

Changing a single-picture selection within folder with grouped JPG and NEF files halts the main thread for 10-15 seconds

STEPS TO REPRODUCE

1. Select all files in a folder  (~1400 files, 21GB)
2. Right click -> Group -> Group Selected by Filename (resulting in ~700 groups since I shoot NEF+JPG)
3. Go to either preview or remain in thumbnails view, change selection with arrows 5-10 times

OBSERVED RESULT

DigiKam becomes unresponsive, the main thread goes to 100% CPU usage for 10-15 seconds

On any subsequent selection change the same happens -- rendering the experience unusable

EXPECTED RESULT

Works as if the files were not grouped

SOFTWARE/OS VERSIONS

Operating System (available in the Info Center app, or by running `kinfo` in a terminal window):
KDE Plasma Version: 6.6.5
KDE Frameworks Version: 6.26.0
Qt Version: 6.11.1
Kernel Version: 7.0.9-arch2-1 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 PRO 7840U w/ Radeon 780M Graphics
Memory: 64 GiB of RAM (58.6 GiB usable)
Graphics Processor: AMD Radeon 780M Graphics


ADDITIONAL INFORMATION

When the main thread shows 100% usage, below is the gbd backtrace for Thread#1, the Thread#1 is consistently stuck in that state during the unresponsive period. The rest of the threads are waiting with different calls (ppoll, epoll, etc)

Thread 1 (Thread 0x7f1520e36cc0 (LWP 57817) "digikam"):
#0  0x00007f154e49bb18 in ??? () at /usr/lib/libQt6Core.so.6
#1  0x00007f154e4aa2ee in QtPrivate::QStringList_contains(QList<QString> const*, QStringView, Qt::CaseSensitivity) () at /usr/lib/libQt6Core.so.6
#2  0x00007f15505095e6 in ??? () at /usr/lib/libdigikamcore.so.9.0.0
#3  0x00007f1550511dc0 in Digikam::LoadingCache::putThumbnail(QString const&, QPixmap const&, QString const&) () at /usr/lib/libdigikamcore.so.9.0.0
#4  0x00007f15504f158c in Digikam::ThumbnailLoadThread::slotThumbnailLoaded(Digikam::LoadingDescription const&, QImage const&) () at /usr/lib/libdigikamcore.so.9.0.0
Comment 1 caulier.gilles 2026-05-23 20:53:36 UTC
This problem must be fixed in 9.1.9 pre-release available as AppImage bundle here :

https://files.kde.org/digikam/
Comment 2 Saveliy Vasilev 2026-05-23 22:24:51 UTC
Confirming it works, thanks a lot!