digikam 8.1 - problem with migration mysql > sqlite

[Maik Qualmann]

The behavior is normal, the face database and thumbnail database are not 
migrated.
Go into the maintenance tool, enable the face detection/recognition section 
and check the box to rebuild the training database. Based on all confirmed 
faces, the facial recognition database is rebuilt.

Maik

Am Montag, 14. August 2023, 15:03:51 CEST schrieb Cesar Inacio Martins:
> Hi,
> 
> After a couple of years without using my DK, I finally returned to it.
> 
> So, I've upgraded from version 7.4 to 8.1.
> I used the Internal MySQL before because I have ~80k photos.
> Now, to solve an old issue with face recognition, I decided to rerun it
> over all my albums to exclude the faces from all photos and detect all
> again ( not people, yet, only detect faces).
> I've done that using MySQL as a database.
> 
> During this process, rereading the manuals, I saw there is an essential
> improvement on sqlite, where it became recommended even for libraries with
> ~100k photos.
> 
> When I finished all face recognition, which took ~ 1 week, I migrate my
> database back to sqlite.
> The migration ran fine.
> However, when I set the DK to sqlite and put my albums to now recognize the
> faces, they give the error message : "face recognition is aborted, because
> there are no identities to recognize. Please add new identities"
> 
> Then I connected both databases and did a count(*) on tables and see at
> recognition.db, no data was imported.
> I tried this migration twice, one with WAL enabled and the second attempt
> with it disabled.
> 
> Is that expected or is it a defect?
> 
> 
> MySQL
> 
> > Settings          |count(*)|
> > ------------------+--------+
> > Settings          |      20|
> > Identities        |     148|
> > IdentityAttributes|     444|
> > FaceMatrices      |   14687|
> > KDTree            |       0|
> 
> SQLite - after migration
> 
> > "Settings"        |count(*)|
> > ------------------+--------+
> > Settings          |       2|
> > Identities        |       0|
> > IdentityAttributes|       0|
> > FaceMatrices      |       0|
> > KDTree            |       0|