<?php
class conn_proxy extends MysqlndUhConnection {
 public function query($res, $query) {
  debug_print_backtrace();
  return parent::query($res, $query);
 }
}
class stmt_proxy extends MysqlndUhPreparedStatement {
 public function prepare($res, $query) {
  debug_print_backtrace();
  return parent::prepare($res, $query);
 }
}
mysqlnd_uh_set_connection_proxy(new conn_proxy());
mysqlnd_uh_set_statement_proxy(new stmt_proxy());

printf("Proxies installed...\n");
$pdo = new PDO("mysql:host=localhost;dbname=test", "root", "");
var_dump($pdo->query("SELECT 1 AS _one FROM DUAL")->fetchAll(PDO::FETCH_ASSOC));

$mysqli = new mysqli("localhost", "root", "", "test");
$mysqli->prepare("SELECT 1 AS _two FROM DUAL");

#0  conn_proxy->query(Resource id #19, SELECT 1 AS _one FROM DUAL)
#1  PDO->query(SELECT 1 AS _one FROM DUAL) called at [example.php:19]
array(1) {
  [0]=>
  array(1) {
    ["_one"]=>
    string(1) "1"
  }
}
#0  stmt_proxy->prepare(Resource id #753, SELECT 1 AS _two FROM DUAL)
#1  mysqli->prepare(SELECT 1 AS _two FROM DUAL) called at [example.php:22]