0.98.1: High CPU use and missing thumbnails

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Foxyrick
Posts: 22
Joined: Wed Mar 15, 2017 10:32 am

0.98.1: High CPU use and missing thumbnails

Post by Foxyrick »

XnView: MP 0.98.1 - 64 bit
OS: Windows 7 64bit

I have noticed this, on occasion, for a while, but took more notice today when I noticed my CPU fans running more loudly. At the time XNViewMP was minimised and I was working on another window.

After writing the below notes, I did some more testing and determined that the issue seems to be caused by quickly moving to the end of the thumbnail view, as soon as XNViewMP loads, before it has had time to finish reading the database for the folder. The progress bar shows it has not finished. It seems to stall, at high CPU use but not continuing to read/display the thumbnails.

I opened a folder to view the images by right-clicking from explorer and choosing 'browse with xnviewmp'. The very first thing I did in XNViewMP was to press the End keyboard button to move to the end of the thumbnails list (I have images sorted in date order so the newest are at the end). The thumbnail display went to the end, but only the very last thumbnail displayed. All of those above it remained with the default thumbnail image, even after several minutes.

The folder is only small, perhaps a few hundred small images, and should have been catalogued already apart from that last, just-added image. There was no noticeable network activity (it's on a NAS) yet XNViewMP was using 10%-12% CPU continually, with the progress bar at the bottom of the thumbnail list which shows it reading/cataloguing the database stuck at about 20% along.

Clicking another (default image) thumbnail above the last one immediately caused all the thumbnails in view to be displayed properly.

After the above, I then scrolled up the thumbnails window, to reveal more (previous) thumbnails which again showed as default images. The progress bar moved a little further, then stopped, and the CPU use remained high. This repeated a few times until all the image thumbnails had been displayed, at which point the CPU use dropped and the progress bar finished.

I can reproduce the above at will, by moving quickly to the end of the thumbnail list.

Trying to reproduce the above in a much larger folder (26000 images) gave a similar but slightly different result. Moving to the end quickly, the progress bar continued to move slowly but if I then scrolled up just one page of thumbnails, the progress bar stopped moving and everything seemed to get stuck just as above. A second try and I did not even have to scroll up; the progress bar and network activity stopped as soon as I pressed the End key.

Effect: XNViewMP continues to use high CPU, but without (it seems) reading the catalogue or displaying the thumbnails.

To reproduce:
1. Start XNViewMP
2. Quickly move to the end of the thumbnails by pressing the End key

Actual behaviour (bug): High CPU use, not reading or displaying thumbnails, clearly no network activity from the database and images on NAS

Expected behaviour: Progress reading the database should continue even though I have moved before it finished loading them all, preferably displaying the thumbnails I am currently viewing as a priority (but certainly not just stopping all activity with high CPU use).
Foxyrick
Posts: 22
Joined: Wed Mar 15, 2017 10:32 am

Re: 0.98.1: High CPU use and missing thumbnails

Post by Foxyrick »

Further information:

Moving to the bottom of the thumbnail pane by pressing the End key before the progress bar finishes stalls XNViewMP as above. Pressing the Home key to move back to the top resumes the progress. This can be repeated, stalling and restarting things, until the loading of thumbnails finally finishes.
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xnview
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Re: 0.98.1: High CPU use and missing thumbnails

Post by xnview »

I'm not able to reproduce, the files are jpeg?
Pierre.
Foxyrick
Posts: 22
Joined: Wed Mar 15, 2017 10:32 am

Re: 0.98.1: High CPU use and missing thumbnails

Post by Foxyrick »

Sorry for the slow reply.

They are a mixture of .jpg, .png and .tga.

I did wonder afterwards if it is related to my Synology NAS... it has some odd behaviour* at times with Windows shares but I'm so used to it, I tend to forget. The image directories and the database are on the NAS. The issue is definitely there; it does it all the time and I can reproduce it at will but maybe it's more my issue than XNView's.

If you can't reproduce it there, then don't waste time on it. If I get chance I'll recreate my database, just in case it's got a problem, and if it still happens I'll copy a bunch of files to a local HD and see if I can reproduce it locally. I guess it won't though.

*Change notifications for one. Synology has just very recently (and quietly) fixed a serious bug about that which has caused problems for some of my applications for a few years. They never admitted it was a bug; their stance was "it works with Windows Explorer, therefore it works". They probably just finally got around to updating the ancient version of one of the library files they were using which I know was where the bug originated.
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