foo.php

<?php

$m = new MongoClient('mongodb://admin:admin@192.168.108.19:27017');
$c = $m->findone->foo;
$c->drop();
$c->insert(['_id' => 1, 'x' => str_repeat('z', 1000)]);
$c->insert(['_id' => 2, 'x' => str_repeat('z', 1000)]);
$c->insert(['_id' => 3, 'x' => str_repeat('z', 1000)]);
$c->insert(['_id' => 4, 'x' => str_repeat('z', 1000)]);
$c->insert(['_id' => 5, 'x' => str_repeat('z', 1000)]);

$t = function ($iterations, $covered) use ($c) {
    printf("Testing with%s covered index queries\n", $covered ? '' : 'out');
    $projection = $covered ? ['_id' => 1] : [];

    printf(" %d iterations: findOne()\n", $iterations);
    $start = microtime(true);

    for ($i = 0; $i < $iterations; $i++) {
        $id = $i % 5 + 1;
        $r = $c->findOne(['_id' => $id], $projection);
    }

    $end = microtime(true);
    printf("  Total time: %f\n", $end - $start);
    printf("  Average time: %f\n", ($end - $start) / $iterations);

    printf(" %d iterations: find()->limit(1)->getNext()\n", $iterations);
    $start = microtime(true);

    for ($i = 0; $i < $iterations; $i++) {
        $id = $i % 5 + 1;
        $r = $c->find(['_id' => $id], $projection)->limit(1)->getNext();
    }

    $end = microtime(true);
    printf("  Total time: %f\n", $end - $start);
    printf("  Average time: %f\n", ($end - $start) / $iterations);
};

$t(10, true);
$t(10, false);
$t(100, true);
$t(100, false);
$t(1000, true);
$t(1000, false);