Gwenview slow to open

[wartnose]

I had been on 18.04 forever. Firefox and Chrome didn't like it anymore so I decided to test 24.04 in a virtual machine. Worked so well I just lived in the virtual machine for a while. I finally bit the bullet and did a clean install on a new SSD. Mostly impressed but Dolphin is a bit slow to open and viewing images in Dolphin folders is really slow because Gwenview takes 15 - 20 seconds to open. Any suggestions? By the way I did save my virtual machine and I moved it to the new drive and tested Dolphin and Gwenview in the virtual machine and they both open quickly. Thanks
i5, 16GB, 2 TB Teamgroup SSD. Kubuntu 24.04

[oshunluvr]

My first thought always is to see whats happening with the application - so open Konsole and launch Dolphin from there and see waht messages show up in Konsole. It might offer a clue.

[wartnose]

This must be an issue from time to time because a Google search "Gwenview slow to open" offers a lot of suggestions. As per one suggestion in Configure Gwenview- Advanced, I unchecked "History: Remember folders and URLs". I rebooted and thought things were fixed, but when I let the computer sit idle and it went to sleep, when I woke it up Dolphin and Gwenview were again slow. I then checked "Thumbnails: Low resource usage mode" because this avoids saving thumbnails and I read this might be an issue. So far so good, but per your suggestion I'll open in terminal next if it doesn't stick.

[wartnose]

Dolphin and Gwenview both open slowly after computer sleeps. Dolphin a little slow. Gwenview very slow.
Opening Dolphin in terminal doesn't show anything. Opening Gwenview in terminal shows this
"kf.i18n.kuit: "Unknown subcue ':whatsthis,' in UI marker in context {@info:whatsthis, %1 the action's text}."
and a long list of these
org.kde.kdegraphics.gwenview.lib: Unresolved mime type
org.kde.kdegraphics.gwenview.lib: Unresolved mime type
org.kde.kdegraphics.gwenview.lib: Unresolved mime type....
BUT Gwenview still opens quickly until computer sleeps.
I could disable sleep but I kinda like the idea. I did not create a swap partition. Is that important for sleep? Could that be the issue?

[Snowhog]

Are you running a Wayland or X11 Plasma Session?

[wartnose]

X11 session

[jlittle]

Are there many files in the directory where gwenview starts? There is an open bug about that, https://bugs.kde.org/show_bug.cgi?id=406431

Conceivably, this is a regression of an earlier gwenview slow startup bug; there's been a few. I had one such in about 20.04, and a fix was going to take six months to reach my kubuntu, so I had to build my own gwenview for that time. From my rusty memory, it was fairly easy.

[wartnose]

I moved some images from backup but not thousands. Dolphin and Gwenview open quickly until I wake my computer from sleep. Then they open slowly. I don't know what happens during sleep but something happens. Probably a bug...maybe a bedbug I tried increasing the swap file size from the default of 512MB to 8GB since some forums suggested you need a larger swap file for sleep. Didn't help. I'll disable sleep and see what happens. This is really kind of a minor issue considering how well Kubuntu works but it is still a bit annoying. Thanks for listening.

[jlittle]

I... the swap file size ... to 8GB ...

Not needed for sleep, aka suspend, but needed for hibernation, or "hybrid sleep". "Hybrid sleep" is writing the hibernation data, then sleeping. If the power goes off, f.ex. the battery runs out, during suspend, data in RAM is lost but the system just restarts as if from hibernation. Proper support for hibernation is spotty and Ubuntu installs with it disabled, or at least it used to. Actually, swap at least as large as RAM size is needed; that might indeed be 8 GB, maybe an older and cheaper laptop.

[wartnose]

This is actually a desktop. i5 quad, 16 GB RAM. SSD. It used to be new and state of the art...10 years ago. I believe under System settings>>Power management>>Energy Saving, Suspend>>Sleep is checked by default. It really sleeps hard. Wiggling the mouse doesn't wake it up. I have to hit the space bar. I unchecked Suspend and Gwenview opens normally now but if it isn't hibernating and it doesn't need swap for sleep I wonder what happens when it sleeps to cause the slowdown. Is there a log I can enable that shows what happens? Of course the log might go to sleep.

[jlittle]

...I have to hit the space bar...

BTW, my experience is that waking by pressing the space bar sends the space to the active window, which can have effects, like restarting a video or inserting a space into a document. If the control, shift, or alt keys cause a wake up, IMO they're better.

I wonder what happens when it sleeps to cause the slowdown.

If I start gwenview in a konsole, I get a bunch of messages. You might see something that gives a clue.