[Digikam-devel] [Bug 131382] New: All thumbnails of album destroyed when using Tag Filters

[Mats Ahlgren]

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http://bugs.kde.org/show_bug.cgi?id=131382         
           Summary: All thumbnails of album destroyed when using Tag Filters
           Product: digikam
           Version: unspecified
          Platform: unspecified
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: NOR
         Component: general
        AssignedTo: digikam-devel kde org
        ReportedBy: ahlgren mit edu


Version:           0.8.2-rc1 (using KDE 3.5.2, Kubuntu Package 4:3.5.2-0ubuntu18 dapper)
Compiler:          Target: i486-linux-gnu
OS:                Linux (i686) release 2.6.15-25-686

- - - - Problem:
When browsing albums, using "Tag Filters" (panel on the right of digiKam) destroys all the thumbnails from an album.

- - - - Reproduction:
Do "ls ~/.thumbnails/normal | wc -l" to count the number of thumbnails stored. If you do this before and after you click on a Tag Filter (1-3 clicks, I forgot), you'll notice that many of your thumbnails are spontaneously deleted!

- - - - Seriousness:
This is moderately serious if you ask me. It's not unreasonable for albums to contain thousands of pictures (especially due to cheap 2GB memory cards), and it takes approximately 5 minutes of processing power to reconstruct an album. Since automatic thumbnail generation for albums is still being implemented, you have to spend 5 minutes of your time hitting page-down as the thumbnails load. Even if that feature was implemented, I personally find it ridiculous to make albums unbrowsable (you can't show it to friends and family) every time you sort by tags (one of the main features of digiKam).

You can avoid this problem by not using Tag Filters... but it seems kind of silly to put a big red warning sign saying "Don't use this popular feature unless you want to wait for 5 minutes while your thumbnails reload."

- - - - Miscellaneous:
One should note that browsing the entire tag database by clicking the Tags panel on the left of digiKam does not destroy your thumbnails.

Related bug: bug 94562

Thumbnail loss is a serious problem since it makes albums rather unusable until all thumbnails are regenerated. I highly suggest that this bug not be closed until someone analyzes the underlying cause of this bug and deems that either 1) This is a one-of-a-kind bug 2) There may be other bugs out there that cause thumbnails to be deleted, but implementing certain safeguards will prevent those bugs from affecting users (and filing a wishlist) or 3) There may be other bugs out there that cause thumbnails to be deleted, but we've determined the underlying problem in the code and have written coding guidelines to avoid repetitions of the bug.