TYPO3 Core

Install extension

Working with alternative database, extension manager and BD comparison wrong analyse

When working with an alternate database, LocalConfiguration.php :

'DB' => [
    'Connections' => [
        'Default' => [
            'charset' => 'utf8',
            'dbname' => 'db-typo3',
            'driver' => 'mysqli',
            'host' => 'localhost',
            'password' => '123456',
            'port' => 3306,
            'user' => 'user-t3',
        ],
        'alternativeDb' => [
            'charset' => 'utf8',
            'dbname' => 'db-alternative',
            'driver' => 'mysqli',
            'host' => 'localhost',
            'password' => '123456',
            'port' => 3306,
            'user' => 'user-alt',
        ],
    ],
    'TableMapping' => [
        'My_Table1' => 'alternativeDb',
        'My_Table2' => 'alternativeDb',
        ]
    ]

and trying to install an extension or compare database with Install Tool result in an error saying that the table from alternative database already exists.

#20: The table with name 'alt-db.My_Table1' already exists. (More information)

Note : same result if 'My_Table1' is not in 'TableMapping'.

The tables from alternative database are created with an external application and they are unknown from Typo3.