Set encoding using the mysql API method

Author: Mytherin

src/mysql_connection.cpp

@@ -30,7 +30,6 @@ MySQLConnection MySQLConnection::Open(const string &connection_string) {
 	MySQLConnection result;
 	result.connection = make_shared_ptr<OwnedMySQLConnection>(MySQLUtils::Connect(connection_string));
 	result.dsn = connection_string;
-	result.Execute("SET character_set_results = 'utf8mb4';");
 	return result;
 }
 

src/mysql_utils.cpp

@@ -247,11 +247,13 @@ MYSQL *MySQLUtils::Connect(const string &dsn) {
 			// retry
 			result =
 			    mysql_real_connect(mysql, "127.0.0.1", user, passwd, db, config.port, unix_socket, config.client_flag);
-			if (result) {
-				return result;
-			}
 		}
-		throw IOException("Failed to connect to MySQL database with parameters \"%s\": %s", dsn, mysql_error(mysql));
+		if (!result) {
+			throw IOException("Failed to connect to MySQL database with parameters \"%s\": %s", dsn, mysql_error(mysql));
+		}
+	}
+	if (mysql_set_character_set(result, "utf8mb4") != 0) {
+		throw IOException("Failed to set MySQL character set");
 	}
 	D_ASSERT(mysql == result);
 	return result;