<?php
$session    = mysql_xdevapi\getSession("mysqlx://user:password@localhost");
$collection = $session->getSchema("addressbook")->getCollection("friends");

$session->startTransaction();
$collection->add( '{"test1":1, "test2":2}' )->execute();

$savepoint = $session->setSavepoint();

$collection->add( '{"test3":3, "test4":4}' )->execute();

$session->releaseSavepoint($savepoint);
$session->rollback();
?>