How to increase limit of checkboxes array

I am trying to get values of more than 1000 checkboxes using PHP but when I get values of more than 1000 checkboxes it doesn't give any result. any solution to increase this limit.

<form action="#" method="post">
    <?php
        $dummy_array_legth = 1000;
        for ($i=0; $i < $dummy_array_legth; $i++) { 
            echo '<input type="checkbox" name="dummy-array[]" value="'. $i .'" checked>';
        }
    ?>
    <input type="text" name="dummy">
    <input type="submit" value="submit" name="submit">
</form>
<?php
    if(isset($_POST['submit'])) {
        print_r($_POST['dummy-array']);
        exit();
    }
?>