Batch Queue Manager and database lock.

[Gilles Caulier]

Hi all,

I remember some fixes done in more and less recent version about BQM
about database lock, especially from Maik.

While this summer i take a lots of panorama in French Alps. I use
typically BQM in background to adjust the colors of target files (JPG)
using a dedicated BQM workflow :

1/ Local Contrast to render image as pseudo HDR (the photo is more luminous).
2/ WB tool to increase the saturation.

For ex : https://goo.gl/photos/FVisJdYHd4i8mZzF9


Processing Pano files of 200Mpx in BQM take age. I don't use
multi-core because my laptop has just 4 cores (i5). I want to use
another one to perform triage, or use editor, or run Panorama tool.

And the problem appear. While BQM tool is running, navigating in album
contents give empty views. No item are visible. When BQM is done, all
re-appear. It's always reproducible.

I don't suspect a database lock, but something wrong with the
ActionThreadBase instance from BQM which reserve all cores and block
database interface which use also ActionThreadBase interface.

Typically, i think that set max cpu core to use with QThreadPool
(inside ActionThreadBase) is something static. One QThreadPool is
certainly a singleton in Qt and changing the number of threads in one
instance of ActionThreadBase change the behavior for all
ActionThreadBase instance.

What do you think about ? Can somebody can confirm the problem ?