isucon.php

<?php
// snippet

// N+1
private function bulkFetch($ids)
{
    $in = array_fill(0, count($ids), '?');

    $sth = $this->dbh->prepare('SELECT * FROM `users` WHERE `id` in (' . implode(',', $in) . ')');
    $r = $sth->execute($ids);
    if ($r === false) {
        throw new \PDOException($sth->errorInfo());
    }
    $users = $sth->fetchAll(PDO::FETCH_ASSOC);

    $result = [];
    foreach ($users as $user) {
        $id = $user['id'];
        $result[$id] = [
            'id' => $id,
            // ...
        ];
    }
    return $result;
}


// guzzle async request
for ($i = 0; $i < 3; $i++) {
    // http_errors -> do not throw exception
    $promise = $client->getAsync('http://localhost:8080/index.php?id=' . $i, ['http_errors' => false]);
    $promise->then(
        function (\Psr\Http\Message\ResponseInterface $res) use (&$results) {
            $results[] = [
                'status' => json_decode($res->getBody()->getContents())->status,
            ];
        }
        //, function () {....}
    );

    $promises[] = $promise;
}

try {
    $responses = all($plist)->wait();
} catch (ClientException $e) {
    $errors[] = json_decode($e->getResponse()->getBody()->getContents());
}