how to switch between mariadb and mysql

Question

my magento2 is reading mariadb server and database is connected to that, I am trying o use mysql instead but I had no luck, it does not recognize the database at all although I have added the following:

    'db' => [
    'connection' => [
        'indexer' => [
            'host' => 'localhost',
            'dbname' => 'm2',
            'username' => 'user',
            'password' => 'xxx',
            'model' => 'mysql4',
            'engine' => 'innodb',
            'active' => '1',
            'persistent' => NULL
        ],
        'default' => [
            'host' => 'localhost',
            'dbname' => 'm2',
            'username' => 'user',
            'password' => 'xxx',
            'model' => 'mysql4',
            'engine' => 'innodb',
            'active' => '1'
        ]
    ],
    'table_prefix' => ''

I also tried using a new user name and password for only mysql to make it understand to read from there but still it is connecting to mariadb instead.

How can I switch it to mysql? my mysql version is 5.7.28 and my magento version is 2.3.1

In Abstract.php line 128:

SQLSTATE[HY000] [1049] Unknown database 'm2'

how can I switch so it understands to read from mysql server instead of mariadb?

Fatal error: Uncaught TypeError: Argument 1 passed to Magento\Framework\Setup\De
claration\Schema\Db\SchemaBuilder::processReferenceKeys() must be of the type ar
ray, null given, called in C:\wamp64\www\scosche-industries\vendor\magento\frame
work\Setup\Declaration\Schema\Db\SchemaBuilder.php on line 127 and defined in C:
\wamp64\www\scosche-industries\vendor\magento\framework\Setup\Declaration\Schema
\Db\SchemaBuilder.php:137
Stack trace:
#0 C:\wamp64\www\scosche-industries\vendor\magento\framework\Setup\Declaration\S
chema\Db\SchemaBuilder.php(127): Magento\Framework\Setup\Declaration\Schema\Db\S
chemaBuilder->processReferenceKeys(NULL, Object(Magento\Framework\Setup\Declarat
ion\Schema\Dto\Schema))
#1 C:\wamp64\www\scosche-industries\vendor\magento\framework\Setup\Declaration\S
chema\SchemaConfig.php(66): Magento\Framework\Setup\Declaration\Schema\Db\Schema
Builder->build(Object(Magento\Framework\Setup\Declaration\Schema\Dto\Schema))
#2 C:\wamp64\www\scosche-industries\vendor\magento\framework\Setup\Declaration\S
chema\UpToDateDe in C:\wamp64\www\scosche-industries\vendor\magento\framework\Se
tup\Declaration\Schema\Db\SchemaBuilder.php on line 137

Answer 1

I think you have used wrong connection for indexer.

 'indexer' => [
            'host' => 'localhost',
            'dbname' => 'm2',
            'username' => 'user',
            'password' => 'xxx',
            'model' => 'mysql4',
            'engine' => 'innodb',
            'active' => '1',
            'persistent' => NULL
        ],

Magento open source version does not have different connection for indexer.It is worked in Commerce version means sperate resource Connection.

Connection Might be like:

    'db' => [
        'table_prefix' => '',
        'connection' => [
            'default' => [
                'host' => 'localhost',
                'dbname' => 'm2',
                'username' => 'user',
                'password' => 'xxx',
                'model' => 'mysql4',
                'engine' => 'innodb',
                'initStatements' => 'SET NAMES utf8;',
                'active' => '1'
            ]
        ]
    ],
    'resource' => [
        'default_setup' => [
            'connection' => 'default'
        ]
    ]

Also, put proper mysql username and password and the mysql user should have read r/write connection at database.