Installing Qt with PostgreSQL drivers macOS m1

[kaptsea]

Hello all

I am trying to install Qt with PostgreSQL sql driver, and have tried almost everything to have the psql drivers before installing Qt.

I have tried installing Postgres via homebrew, via the official installer and the Postgres.app and libpq, libpqxx via homebrew but neither the offline or online installer detects Postgres.

Has anyone managed to do this?

[SGaist]

Hi and welcome to devnet,

Start your application with the QT_DEBUG_PLUGINS environment variable set to 1. It will show you a dump of what happens when the plugins are getting loaded and why it failed.

[kaptsea]

@SGaist said in Installing Qt with PostgreSQL drivers macOS m1:

QT_DEBUG_PLUGINS

Thank you so much for your reply.

Unfortunately I am not really familiar with the output.

QFactoryLoader::QFactoryLoader() checking directory path "/Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers" ...
QFactoryLoader::QFactoryLoader() looking at "/Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlite.dylib"
Found metadata in lib /Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlite.dylib, 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 "/Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlodbc.dylib"
Found metadata in lib /Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlodbc.dylib, 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 "/Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib"
Found metadata in lib /Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib, 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() checking directory path "/Users/USERNAME/src/audioManager/cmake-build-debug/sqldrivers" ...
Cannot load library /Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib: (dlopen(/Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib, 133): Library not loaded: /Applications/Postgres.app/Contents/Versions/9.6/lib/libpq.5.dylib
  Referenced from: /Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib
  Reason: image not found)
QLibraryPrivate::loadPlugin failed on "/Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib" : "Cannot load library /Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib: (dlopen(/Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib, 133): Library not loaded: /Applications/Postgres.app/Contents/Versions/9.6/lib/libpq.5.dylib\n  Referenced from: /Users/USERNAME/Qt/5.15.2/clang_64/plugins/sqldrivers/libqsqlpsql.dylib\n  Reason: image not found)"
QSqlDatabase: QPSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QODBC QODBC3 QPSQL QPSQL7
"Driver not loaded Driver not loaded"

From what I collect, it says it cannot find the driver and it cannot find the driver because when I installed qt, even though I had installed Postgres and qt-postgres (from brew), it could not find the dev libs. Does that make sense?

[SGaist]

The PSQL driver is found that is not the issue.

What happens here is that the driver has been built using libpq coming with the Postgres App which is the official package provided by the project to get a quick and easy installation of PostgreSQL on macOS.

See this path

@kaptsea said in Installing Qt with PostgreSQL drivers macOS m1:

/Applications/Postgres.app/Contents/Versions/9.6/lib/libpq.5.dylib

Where did brew install PostgreSQL ?
Can you locate the libpq library in there ?
If you find it, then what you can do is use install_name_tool to update that path to match the one from the libpq dylib you have on your machine.

[Albert M.]

@kaptsea @SGaist -

I hope this message finds you well. I'm reaching out to you because I've been having some trouble with setting up a PostgreSQL database connection on my Apple Silicon M2 machine.

Specifically, I keep getting the error message "QSqlDatabase: QPSQL driver not loaded" when attempting to establish a connection using the Qt SQL module.

I've read almost every thread and post on this topic, but unfortunately, I haven't been able to find a solution that works for me. I'm starting to feel a bit stuck, and I was hoping that you might have some experience or insight that could help me resolve this issue.

I am using install_name_tool to update the path should help resolve the issue. Just to confirm, you would need to run the following command in your terminal, replacing the path with the location of your libpq dylib:

1. POSTGRES@15 installed using Homebrew

➜  lib otool -L libpq.5.dylib

libpq.5.dylib:
	/usr/local/opt/postgresql@15/lib/libpq.5.dylib (compatibility version 5.0.0, current version 5.15.0)
	/usr/local/opt/gettext/lib/libintl.8.dylib (compatibility version 12.0.0, current version 12.0.0)
	/usr/local/opt/openssl@1.1/lib/libssl.1.1.dylib (compatibility version 1.1.0, current version 1.1.0)
	/usr/local/opt/openssl@1.1/lib/libcrypto.1.1.dylib (compatibility version 1.1.0, current version 1.1.0)
	/usr/local/opt/krb5/lib/libgssapi_krb5.2.2.dylib (compatibility version 2.0.0, current version 2.2.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1319.0.0)
	/System/Library/Frameworks/LDAP.framework/Versions/A/LDAP (compatibility version 1.0.0, current version 2.4.0)

2. POSTGRES.APP

➜ lib otool -L libpq.5.dylib

libpq.5.dylib (architecture x86_64):
	/Applications/Postgres.app/Contents/Versions/15/lib/libpq.5.dylib (compatibility version 5.0.0, current version 5.15.0)
	@loader_path/libssl.3.dylib (compatibility version 3.0.0, current version 3.0.0)
	@loader_path/libcrypto.3.dylib (compatibility version 3.0.0, current version 3.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1311.100.3)
libpq.5.dylib (architecture arm64):
	/Applications/Postgres.app/Contents/Versions/15/lib/libpq.5.dylib (compatibility version 5.0.0, current version 5.15.0)
	@loader_path/libssl.3.dylib (compatibility version 3.0.0, current version 3.0.0)
	@loader_path/libcrypto.3.dylib (compatibility version 3.0.0, current version 3.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1311.100.3)```

3. install_name_tool command

install_name_tool -change /usr/local/opt/postgresql@15/lib/libpq.5.dylib /Applications/Postgres.app/Contents/Versions/15/lib/libpq.5.dylib libpq.5.dylib

 The issue still after I ran the command "QSqlDatabase: QPSQL driver not loaded"

can you please help?

[SGaist]

@Albert-M hi, why are you changing the path of the PostgreSQL library ? You should update the one from the Qt plugin.