Benchmark session lifetime condition: Mongo vs PHP

mongo_session_bench.php

<?php

$mongo = new MongoClient();
$db = $mongo->test;
$collection = $db->selectCollection('session');
$sessionCount = $argv[1];
$sampleCount = $argv[2];
$samples = [];

// Setup collection
$collection->drop();

$bulk = [];
for ($i=0; $i<$sessionCount; $i++) {
    $data = [
        '_id'  => "sess_" + $i,
        'time' => new MongoDate(time() - rand(0, 3600)),
        'data' => new MongoBinData("abc", MongoBinData::BYTE_ARRAY)
    ];

    if (count($samples) < $sampleCount) {
        $samples[] = $data;
    }

    $bulk[] = $data;

    if (count($bulk) == 1000) {
        $collection->batchInsert($bulk);
        $bulk = [];
    }
}

$compare = new MongoDate(time() - 1800);


// Benchmark
$t[0] = microtime(true);

for ($i=0; $i<$sampleCount; $i++) {
    $doc = $collection->findOne(['_id' => $samples[$i]['_id']]);
    if ($doc['time']->sec < $compare->sec) {}
}

$t[1] = microtime(true);

for ($i=0; $i<$sampleCount; $i++) {
    $doc = $collection->findOne(['_id' => $samples[$i]['_id'], 'time' => ['$gt' => $compare]]);
}

$t[2] = microtime(true);

// Results
echo 'PHP  : ', ($t[1] - $t[0]), "s\n";
echo 'Mongo: ', ($t[2] - $t[1]), "s\n";