Driver not loaded (MySQL)

[ocgltd]

When I run my app (from Qt Creator 5.15.2) on Ubutu 23, my code reports the database error "Driver not loaded". I assumed it was that the MySQL plugin was not found, so I built it per other posts. It actually looked like it was already built, but I built it anyways.

Next I checked my apps' dependencies:

ldd /myapp
        linux-vdso.so.1 (0x00007fff89592000)
        libQt5Network.so.5 => /opt/Qt/5.15.2/gcc_64/lib/libQt5Network.so.5 (0x00007f6c23e00000)
        libQt5Xml.so.5 => /opt/Qt/5.15.2/gcc_64/lib/libQt5Xml.so.5 (0x00007f6c23a00000)
        libQt5Sql.so.5 => /opt/Qt/5.15.2/gcc_64/lib/libQt5Sql.so.5 (0x00007f6c23600000)
        libQt5Core.so.5 => /opt/Qt/5.15.2/gcc_64/lib/libQt5Core.so.5 (0x00007f6c22e00000)
        libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f6c22a00000)
        libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f6c2427b000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f6c22600000)
        libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f6c24276000)
        libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f6c24258000)
        libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f6c24253000)
        libgssapi_krb5.so.2 => /lib/x86_64-linux-gnu/libgssapi_krb5.so.2 (0x00007f6c241ff000)
        libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f6c23d17000)
        libicui18n.so.56 => /opt/Qt/5.15.2/gcc_64/lib/libicui18n.so.56 (0x00007f6c22000000)
        libicuuc.so.56 => /opt/Qt/5.15.2/gcc_64/lib/libicuuc.so.56 (0x00007f6c21c00000)
        libicudata.so.56 => /opt/Qt/5.15.2/gcc_64/lib/libicudata.so.56 (0x00007f6c20200000)
        libgthread-2.0.so.0 => /lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f6c241f8000)
        libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f6c238b9000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f6c242b8000)
        libkrb5.so.3 => /lib/x86_64-linux-gnu/libkrb5.so.3 (0x00007f6c23c4e000)
        libk5crypto.so.3 => /lib/x86_64-linux-gnu/libk5crypto.so.3 (0x00007f6c241ca000)
        libcom_err.so.2 => /lib/x86_64-linux-gnu/libcom_err.so.2 (0x00007f6c241c4000)
        libkrb5support.so.0 => /lib/x86_64-linux-gnu/libkrb5support.so.0 (0x00007f6c241b7000)
        libpcre2-8.so.0 => /lib/x86_64-linux-gnu/libpcre2-8.so.0 (0x00007f6c22d66000)
        libkeyutils.so.1 => /lib/x86_64-linux-gnu/libkeyutils.so.1 (0x00007f6c241ae000)
        libresolv.so.2 => /lib/x86_64-linux-gnu/libresolv.so.2 (0x00007f6c238a6000)

When I show the output of QSqlDatabase::drivers() I see:
("QSQLITE", "QMARIADB", "QMYSQL", "QMYSQL3", "QODBC", "QODBC3", "QPSQL", "QPSQL7")

so I think the driver is there, and according to ldd all libraries are found. Yet the error continues. How do I solve this?

My code (which worked fine on my old dev box) is:

driver="QMYSQL";
m_db = new QSqlDatabase();
 *m_db = QSqlDatabase::addDatabase(driver,QUuid::createUuid().toString());  // Create connection with unique name each time
 m_db->setHostName(programSettings->database_hostname());
 m_db->setDatabaseName(programSettings->database_databasename());
 m_db->setUserName(programSettings->database_username());
 m_db->setPassword(programSettings->database_password());

[Christian Ehrlicher]

@ocgltd said in Driver not loaded (MySQL):

Why would the db not be open...perhaps the driver error?

No, for sure not. You did something wrong. But without a minimal, compilable example we can not say what.

[Christian Ehrlicher]

@ocgltd Start your app with the env var QT_DEBUG_PLUGINS and take a look at the console output.

[ocgltd]

I got interesting output...the file /opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlmysql.so exists, and has 777permissions:

QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlmysql.so"
Found metadata in lib /opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlmysql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL",
            "QMARIADB"
        ]
    },
    "archreq": 0,
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 331520
}

[Christian Ehrlicher]

Please post the full output. The debug file does not matter.

[ocgltd]

@Christian-Ehrlicher Here is full output :

QFactoryLoader::QFactoryLoader() checking directory path "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlite.so"
Found metadata in lib /opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlite.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QSQLITE"
        ]
    },
    "archreq": 0,
    "className": "QSQLiteDriverPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("QSQLITE")
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlite.so.debug"
"The shared library was not found." 
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlmysql.so"
Found metadata in lib /opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlmysql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QMYSQL3",
            "QMYSQL",
            "QMARIADB"
        ]
    },
    "archreq": 0,
    "className": "QMYSQLDriverPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("QMYSQL3", "QMYSQL", "QMARIADB")
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlmysql.so.debug"
"The shared library was not found." 
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlodbc.so"
Found metadata in lib /opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlodbc.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QODBC3",
            "QODBC"
        ]
    },
    "archreq": 0,
    "className": "QODBCDriverPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("QODBC3", "QODBC")
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlodbc.so.debug"
"The shared library was not found." 
         not a plugin
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlpsql.so"
Found metadata in lib /opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlpsql.so, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "archreq": 0,
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 331520
}


Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() looking at "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlpsql.so.debug"
"The shared library was not found." 
         not a plugin
QFactoryLoader::QFactoryLoader() checking directory path "/mnt/lserver/data/development/licensecreator/bin/debug/sqldrivers" ...
loaded library "/opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/libqsqlmysql.so"

And here is the content of /opt/Qt/5.15.2/gcc_64/plugins/sqldrivers/

drwxr-xr-x  2 root root    4096 Aug 14 21:09 ./
drwxr-xr-x 36 root root    4096 Nov  6  2020 ../
-rwxr-xr-x  1 root root 1476256 Aug 14 21:08 libqsqlite.so*
-rw-r--r--  1 root root 6334248 Aug 14 21:08 libqsqlite.so.debug
-rwxr-xr-x  1 root root  111248 Aug 14 21:06 libqsqlmysql.so*
-rwxrwxrwx  1 root root 1319264 Aug 14 21:06 libqsqlmysql.so.debug*
-rwxr-xr-x  1 root root  119360 Nov  6  2020 libqsqlodbc.so*
-rw-r--r--  1 root root 1204520 Nov  6  2020 libqsqlodbc.so.debug
-rwxr-xr-x  1 root root  115032 Nov  6  2020 libqsqlpsql.so*
-rw-r--r--  1 root root 1292544 Nov  6  2020 libqsqlpsql.so.debug

A little more info...my call to m_db->open() succeeds and then I perform a query. I see the prepare fails with:

QSqlQuery::prepare: database not open

I'm not sure if that is the cause, a symptom, or irrelevant. Why would the db not be open...perhaps the driver error?

[Christian Ehrlicher]

The output shows that the plugin gets properly loaded (if this was really the complete output).

[Christian Ehrlicher]

@ocgltd said in Driver not loaded (MySQL):

Why would the db not be open...perhaps the driver error?

No, for sure not. You did something wrong. But without a minimal, compilable example we can not say what.

[ocgltd]

@Christian-Ehrlicher In building my MRE I found a mistake I hadn't noticed before...solved :)

Thanks