Having a server with

[server]

character-set-server  = utf8mb3

collation-server      = utf8mb3_swedish_ci

the command line client, return "utf8mb3_general_ci" as result of

SHOW VARIABLES LIKE 'collation_connection';

both when connecting to the MariaDB server directly, and when connecting via Maxscale.

A PHP program on the other hand also returns "utf8mb3_general_ci" when connecting via Maxscale, but "utf8mb3_swedish_ci" when connecting to MariaDB server directly.

This breaks PHP applications that do not explicitly set client character set / collation.

PHP test code I used:

<?php

function test($host) 

{

  $mysqli = new mysqli($host,"vagrant","Secret23!");

  if ($mysqli -> connect_errno) {

    echo "Failed to connect to MySQL: " . $mysqli -> connect_error;

    exit();

  }

  echo "Host: $host\n";

  if ($result = $mysqli -> query("SHOW VARIABLES LIKE 'collation_connection'")) {

    while($row = mysqli_fetch_assoc($result)){

      print_r($row);

    }

    $result -> free_result();

  }

  echo "\n";

  $mysqli -> close();

}

test("master");

test("maxscale");

?>

Note that PHP does not use a bundled version of libmysqlclient anymore by default, but its own "mysqlnd" implementation of the client protocol.