mongoDB insert benchmark

mongo.php

<?php
try {
  // open connection to MongoDB server
  $conn = new Mongo('localhost');

  // access database
  $db = $conn->benchmark;

  // access collection
  $collection = $db->coll;
for ($i=0;$i<5000000;$i++) {
  // insert a new document
  $item = array(
"timestamp" => 1303471614,
"client_ip" => "127.0.0.1",
"host_address" => "http://www.host.url",
"position" => 1,
"user_hash" => 10130347161597979797979797979797,
"host_name" => "www.example.co",
"shop_hash" => "be0290b2320e475736048ecfdf688467",
"shop_product_id" => 1,
"cost" => 0.77
  );
  $collection->insert($item);
  echo $item . "_id";
}
  // disconnect from server
  $conn->close();
} catch (MongoConnectionException $e) {
  die('Error connecting to MongoDB server');
} catch (MongoException $e) {
  die('Error: ' . $e->getMessage());
}
?>