function generatestring($length = 8)
{
    $chars = 'abdefhiknrstyzABDEFGHKNQRSTYZ23456789';
    $numChars = strlen($chars);
    $string = '';
    for ($i = 0; $i < $length; $i++) {
        $string .= substr($chars, rand(1, $numChars) - 1, 1);
    }
    return $string;
}

$user = 'root';
$pass = 'root';
$dbh = new PDO('mysql:host=localhost;dbname=test_innodb', $user, $pass);

for ($i = 1; $i <= 1000000000; $i++) {

    if ($i % 1000 == 0) {
        echo "\t== Старт == \nЗапрос $i\n";
    }

    $varchar = generatestring(255);
    $bigint = mt_rand(10000000, 1000000000);
    $text = generatestring(9999);
    $longtext = generatestring(9999);
    $statement = $dbh->prepare("INSERT INTO tableForTest(`varchar`, `bigint`, `text`, `longtext`) VALUES('$varchar', '$bigint', '$text', '$longtext')");
    $statement->execute();

    if ($i % 15000 == 0) {
        echo "Очистка $i\n";
        $dbh->exec("DELETE FROM tableForTest WHERE `bigint` % 3 = 1");
    }
    if ($i % 10000 == 0) {
        echo "Очистка $i\n";
        $dbh->exec("DELETE FROM tableForTest WHERE `bigint` % 4 = 0");
    }
    if ($i % 54321 == 0) {
        echo "Очистка $i\n";
        $dbh->exec("DELETE FROM tableForTest WHERE `bigint` != 0");
    }
    if ($i % 1000 == 0) {
        echo "\t== Конец == \n\n";
    }
}

echo "Финал\n";
$dbh->exec("DELETE FROM tableForTest WHERE `bigint` != 0");