QPSL driver is not loaded Win10 MSVC 2015 x64

[koronabora]

Hello! I need some help with the most popular question at this section: QPSQL driver is not loaded error.

OS: Windows 10 x64
MSVC 2015 x64
PostgreSQL: 9.5.2 x64
Qt sql driver: from official installer msvc2015_x64

Dependencies of all libraries checked:
qt plugin:
https://yadi.sk/i/J8ybogz1qsamK
warngings:
https://yadi.sk/i/W8giYWPiqsapa
psql:
https://yadi.sk/i/PON_W6YrqsawK
warngings:
https://yadi.sk/i/vx_fjPM-qsazs

Some code:

bool SQLContorller::_init()
{
	_sqlBase = new QSqlDatabase();
	_sqlBase->addDatabase(_SQL_DRIVER); //"QPSQL"
	_sqlBase->setHostName(_host);
	_sqlBase->setPort(_port);
	_sqlBase->setDatabaseName(_baseName);
	_sqlBase->setUserName(_name);
	_sqlBase->setPassword(_pass);
	return _sqlBase->open();
}

Debug information from QT:

QFactoryLoader::QFactoryLoader() looking at "C:/Users/KOT/Documents/Visual Studio 2015/Projects/MoneyManagement/x64/Debug/sqldrivers/qsqlpsqld.dll"
Found metadata in lib C:/Users/KOT/Documents/Visual Studio 2015/Projects/MoneyManagement/x64/Debug/sqldrivers/qsqlpsqld.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "className": "QPSQLDriverPlugin",
    "debug": true,
    "version": 329216
}


Got keys from plugin meta data ("QPSQL7", "QPSQL")
"15:00:33 : Starting user manager"
loaded library "C:/Users/KOT/Documents/Visual Studio 2015/Projects/MoneyManagement/x64/Debug/sqldrivers/qsqlpsqld.dll"
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\uxtheme.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\dwmapi.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\NapiNSP.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\pnrpnsp.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\nlaapi.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Users\KOT\Documents\Visual Studio 2015\Projects\MoneyManagement\x64\Debug\sqldrivers\qsqlpsqld.dll'. Cannot find or open the PDB file.
'MoneyManagement.exe' (Win32): Loaded 'C:\Users\KOT\Documents\Visual Studio 2015\Projects\MoneyManagement\x64\Debug\libpq.dll'. Cannot find or open the PDB file.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\Wldap32.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Users\KOT\Documents\Visual Studio 2015\Projects\MoneyManagement\x64\Debug\ssleay32.dll'. Cannot find or open the PDB file.
'MoneyManagement.exe' (Win32): Loaded 'C:\Users\KOT\Documents\Visual Studio 2015\Projects\MoneyManagement\x64\Debug\libintl-8.dll'. Module was built without symbols.
'MoneyManagement.exe' (Win32): Loaded 'C:\Users\KOT\Documents\Visual Studio 2015\Projects\MoneyManagement\x64\Debug\libeay32.dll'. Cannot find or open the PDB file.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\secur32.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\msvcr120.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Users\KOT\Documents\Visual Studio 2015\Projects\MoneyManagement\x64\Debug\libiconv-2.dll'. Module was built without symbols.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\sspicli.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\msctf.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\mswsock.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\winrnr.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\wshbth.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\clbcatq.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\DataExchange.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\d3d11.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\dcomp.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\dxgi.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\twinapi.appcore.dll'. Symbols loaded.
'MoneyManagement.exe' (Win32): Loaded 'C:\Windows\System32\bcrypt.dll'. Symbols loaded.
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/KOT/Documents/Visual Studio 2015/Projects/MoneyManagement/x64/Debug/accessible" ...
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/KOT/Documents/Visual Studio 2015/Projects/MoneyManagement/x64/Debug/accessiblebridge" ...
"15:00:34 : C:/Users/KOT/Documents/Visual Studio 2015/Projects/MoneyManagement/x64/Debug"
"15:00:34 : Error while connecting to database!"
"15:00:34 : Driver not loaded Driver not loaded"

Thank you for help!

[koronabora]

I builded psql plugin using msvc compiler with postgres 9.5.2. Nothing changed.

Please, could anybody say how to debug this situation: why plugin is not loading? There are no logs about this.

Thank you!

[SGaist]

Hi and welcome to devnet,

Do you also have the folder where the PostgreSQL dlls are in your PATH environment variable ? If not, then simply got to the run part of the Project panel and add it there.

[koronabora]

@SGaist
Yes, global %PATH% includes paths to PostgreSQL's dlls:
https://yadi.sk/i/DP7N4Xx8qvCSB

And these dll is in a root near a project binaries:

ssleay32.dll, iconv.dll, libeay32.dll, libiconv-2.dll, libintl-8.dll, libpq.dll, libxml2.dll, libxslt.dll, zlib1.dll

P.S.

I'm modified psql driver code by appending some output to console, but nothing appears at console after driver loading:

QSqlDriver* QPSQLDriverPlugin::create(const QString &name)
{
    if (name == QLatin1String("QPSQL") || name == QLatin1String("QPSQL7")) {
        QPSQLDriver* driver = new QPSQLDriver();
        std::cout << "Driver loaded by main";
        return driver;
    }
    std::cout << "Driver not loaded by main";
    return 0;
}

[SGaist]

After re-reading your plugin loading output, there something strange, did you copy the plugin in your application after building it ?

It should rather go in Qt's plugins SQL sub folder

[koronabora]

I'm sorry.

Using command line to start application:

@echo off
MoneyManagement.exe > out.txt

I see this in file "out.txt":

Driver loaded by main

In lastSqlError variable the same:

Driver not loaded Driver not loaded

And there are no error messages in MSVC output.

What I have to do?

P.S.

After appending debug output to all methods inside "qsql_psql_p.h" I saw this:

Plugin consructor called.
private sql driver constructor called
QPSQLDriver constructor 1
Driver loaded by mainQPSQLDriver close
QPSQLDriver isOpen
QPSQLDriver destructor

[SGaist]

After re-reading your code sample I just realized: you're using QSqlDatabase wrongly. You are currently trying to open an invalid database object.

addDatabase is a static function. See the detailed description of QSqlDatabase to see how it's done

[koronabora]

@SGaist

Thank you again!

_sqlBase = new QSqlDatabase();
	*_sqlBase = QSqlDatabase::addDatabase(_SQL_DRIVER); //"QPSQL"

Now all is ok.

[SGaist]

That's wrong, don't allocate _sqlBase on the heap.

[koronabora]

@SGaist

Could you explain to me, why?
Thank you.

[SGaist]

One of the reason is explained in QSqlDatbase::removeDatabase.