Qt app with MySQL works in developing machine but not in deploying one

[anda_skoa]

You can try running your application in an environment that has variable QT_DEBUG_PLUGINS set to 1, making Qt's plugin loading code log what it is doing.

Possible causes can be things like a plugin of a different Qt version being found before the correct one.

Cheers,
_

[Laureta]

You can try running your application in an environment that has variable QT_DEBUG_PLUGINS set to 1

Well, I did that; and the first thing I saw was that I was using a debug plugin.
It's my fault, my laziness, I tried to compile the plugin from Qt Creator without realizing it was in debug mode !!!!
So, I rolled my sleeves up to find the libraries and headers through the file system, and finally I get compiled the plugin from console.

These are the log's relevant parts on my dev machine (working) log.txt
And this is the complete log on the deploy machine log_deploy.txt
Here you can see the application's folder tree on the deploy machine folders_snapshot.png

As you can see, the mysql plugin is not loaded on deploy machine. What might be the cause?

Also, I get a warning when platform plugin is loaded: the plugin <path-to-application-platforms> libqxcb.so uses incompatible Qt library (5.4.1) [release].

In deploy machine, there are Qt 4.8 and Qt 5.1 shared libraries (at /usr/lib/i386-linux-gnu). How can I force to load the libraries distributed with my application, instead of those earlier?

[anda_skoa]

You can set an override search path for the runtime linker using the LD_LIBRARY_PATH environment variable in your start script:

export LD_LIBRARY_PATH=/your/library/path:$LD_LIBRARY_PATH

export LD_LIBRARY_PATH=/your/library/path:$LD_LIBRARY_PATH

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If you do that in a shell, ldd will also use it, so you can verify which Qt is picked up for your application.

Cheers,
_