Yii2-sphinx multiple server handling

[klimov-paul]

Migrated from yiisoft/yii2#4849

@tibee :

since yii2-sphinx extends yii2 db handling capabilities, it does already support multiple master and multiple slave servers for load balancing and read-write separation.

However, since Sphinx does not support replication, cannot be configured that way as for example, MySQL replication. So, if I need to run multiple servers for load balancing, I have to set up multiple servers (as logical masters, without logical slaves), and I would need to write in every master.

My component config would be:

 'sphinx' => [
        'class' => 'yii\sphinx\Connection',
        'masters' => [
            ['dsn' => 'mysql:host=192.168.1.20;port=4300'],
            ['dsn' => 'mysql:host=192.168.1.21;port=4300'],
        ],
        'masterConfig' => [
            'username' => '',
            'password' => '',
        ],
    ],

The current implementation chooses only one master on a write operation, causing inconsistency.
A feature request would be the high-level support of multiple servers, meaning a loop would do the write operations on ALL masters.

[klimov-paul]

I do not consider this issue as general enough.
For the Sphinx it is much more common to use distibuted indexes.
Also the possible fix should be provided at yii\db\* layer not here.