catalog directory emptied when opening second instance of xnviewmp

[rmtk]

to reproduce:
1. open the first instance of xnviewmp
2. open a new folder and xnviewmp starts generating thumbnails of the folder
3. before it finishing generating thumbnails, open the second instance of xnviewmp
4. you will find XnView.db corrupts and catalog directory in settings emptied, you have to regenerate all thumbnails

It's safe to open the second xnviewmp after all thumbnails generated on the first one.

[xnview]

you can reproduce each time? When i test, the second instance was locked until thumbnails was built

[masterjp]

I also did different tests with catalog and 2 instances of XnViewMP.
Both use the same database.

If you browse a new picture folder with the first instance,
it is not possible to browser and view thumbnails of a known folder with the second instance of XnviewMP.

Problem: The XnViewMP instance, which currently generates the thumbnails, block the thumbnail database file.
So it is not possible to view the thumbnails of the folder which were generated in the past.

If the thumbnail are generated, the other XnviewMP instance will view other folders as expected and the database file is no longer locked.

Maybe it is not possible to read and write the database at the same time with two instances of XnViewMP.

[xnview]

Maybe it is not possible to read and write the database at the same time with two instances of XnViewMP.

It's not possible, only multiple read is possible

[masterjp]

Thank you for the details, how XnViewMP works.