TYPO3 Core

Affected Versions
6.1, 6.2

This Happens:
Installer did not got a DB-Connection, even if userdata and Password is right and work for other CMS and Shop-Software on same host.

This is the cause:
The Driver for the DB is not set.

Detail-Information
Have a Look into typo3/sysext/dbal/Classes/Database/DatabaseConnection.php, at Line 2463.
There are some overwrites for $this->handlerCfg['_DEFAULT']['config'] which is initiate at Line 75.

There you see the '_DEFAULT' array:

public $handlerCfg = array(
        // See manual.
        '_DEFAULT' => array(
            'type' => 'native',
            'config' => array(
                'username' => '',
                // Set by default (overridden)
                'password' => '',
                // Set by default (overridden)
                'host' => '',
                // Set by default (overridden)
                'database' => '',
                // Set by default (overridden)
                'driver' => '',
                // ONLY "adodb" type; eg. "mysql" 
                'sequenceStart' => 1,
                // ONLY "adodb", first number in sequences/serials/...
                'useNameQuote' => 0,
                // ONLY "adodb", whether to use NameQuote() method from ADOdb to quote names
                'quoteClob' => FALSE
            )
        )
    );

If you set 'driver' to 'mysql', it works like a charm.

May the overwriting for the driver missed in the Function sql_pconnect ??