Bug 448082

Summary: Thumbnail maintenance always clears faces thumbnails
Product: [Applications] digikam Reporter: testvonmir
Component: Maintenance-EngineAssignee: Digikam Developers <digikam-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: metzpinguin
Priority: NOR    
Version First Reported In: 7.4.0   
Target Milestone: ---   
Platform: Microsoft Windows   
OS: Microsoft Windows   
Latest Commit: https://invent.kde.org/graphics/digikam/commit/02750c9d446315679698708cde290a96f0204f6d Version Fixed/Implemented In: 7.5.0
Sentry Crash Report:

Description testvonmir 2022-01-07 18:04:07 UTC 
SUMMARY
***
When using the maintenance tool to clean the Thumbnail database, thumbnails of tagged faces disappear and need to be rebuild. The size of the database "thumbnails-digikam.db" stays the same throughout the process, even when the thumbnails are rebuild afterwards.
***


STEPS TO REPRODUCE
1. Run Tools -> Maintenance -> Perform database cleaning with options:
"Also clean up the thumbnail database" & "Also shrink all databases when possible" (the faces option seemed to make no difference, if checked or not)
2. Wait until task is finished
3. Check if thumbnails of faces in "People" tab are visible

OBSERVED RESULT
After running the maintenance, all face thumbnails in the People section (lefthand side of digikam) are gone and digikam starts rebuilding them again. The size of the database meanwhile stays the same.

EXPECTED RESULT
Only orphaned thumbnails (from images that do not exist or similar) should be removed.
If People's thumbnails are removed, the database size should decrease.

SOFTWARE/OS VERSIONS
Windows 10 Pro, 21H2, 19044.1415

ADDITIONAL INFORMATION
Database cleaning should not remove thumbnails from images/regions which are still in use, right? For the images (under albums), this works as intended, but not for the People tab.
Are the thumbnails for the People section even stored in this file or somewhere else? Or am I missing something? Is this behaviour intentional?
After this maintenance, all face thumbnails are rebuilt, when I select the People tab which takes quite a time (images on not-very-fast etwork drive).

I don't know if another bug I experienced (or some information I provided there) might be related in any form:
https://bugs.kde.org/show_bug.cgi?id=448079
Comment 1 Maik Qualmann 2022-01-07 20:38:49 UTC 
Git commit 02750c9d446315679698708cde290a96f0204f6d by Maik Qualmann.
Committed on 07/01/2022 at 20:37.
Pushed by mqualmann into branch 'master'.

fix calculation of the face rectangle to find the thumbnail
FIXED-IN: 7.5.0

M  +7    -2    core/utilities/maintenance/databasetask.cpp

https://invent.kde.org/graphics/digikam/commit/02750c9d446315679698708cde290a96f0204f6d
Comment 2 Maik Qualmann 2022-01-07 20:47:17 UTC 
One more word about databases. Databases never get smaller, even if they delete data. Deleted data are only marked that they have been deleted and are later overwritten with new data. A vacuum process must be started to reduce the size of the database. This process does not always work correctly in digiKam-7.4.0 (window does not appear) and has already been fixed in digiKam-7.5.0.

Maik
Comment 3 Maik Qualmann 2022-01-07 21:17:28 UTC 
Git commit a95912a6740cfba83679c01c02aed4ae7d734a23 by Maik Qualmann.
Committed on 07/01/2022 at 21:16.
Pushed by mqualmann into branch 'master'.

do not delete the unused original rectangle thumbnails

M  +5    -3    core/utilities/facemanagement/database/faceutils.cpp
M  +22   -14   core/utilities/maintenance/databasetask.cpp

https://invent.kde.org/graphics/digikam/commit/a95912a6740cfba83679c01c02aed4ae7d734a23
Comment 4 testvonmir 2022-01-09 09:16:13 UTC 
Ah, I see. Thanks for clarifying and fixing.
So maybe the vacuuming also did not work correctly for me as you mentioned. Afair I also tried shrinking the databases under maintenance afterwards.