Efficiently loop over huge number of posts

Call a external script:
Your function look like this:

<?php    
function modify_posts() {
    $number_posts = 10;
    $offset = 0;
    $success="success";

    while ( 'success' === $success ) {

        $url = add_query_arg(
                array(
                    'num' => $number_posts,
                    'off' => $offset,
                    'abs' => urlencode( ABSPATH )
                    ),

                    plugins_url( 'remote_get.php', __FILE__ )

        );

        $response = wp_remote_get( $url );

        if ( ! is_wp_error( $response ) ) {

            $success = json_decode( $response['body'] );

            if ( 'success' != $success ) {
                // something went wrong in remote_get.php
            }

        } else {
            // wp_remote_get() throws an error...
        }

        $offset += $number_posts;

        printf( "%d -> %s<br>", $offset, $success );

    }

}

remote_get.php

<?php
$offset = filter_input( INPUT_GET, 'off', FILTER_SANITIZE_NUMBER_INT );
$number_posts = filter_input( INPUT_GET, 'num', FILTER_SANITIZE_NUMBER_INT );
$abspath = urldecode( filter_input( INPUT_GET, 'abs', FILTER_SANITIZE_URL ) );

require_once $abspath . 'wp-load.php';

$posts = get_posts(
        array(
                'post_status' => 'publish',
                'posts_per_page' => $number_posts,
                'offset' => $offset
                )
        );


if ( ! empty( $posts ) ) {

    foreach ( $posts as $post ) {

        // do wired things here

        $result="success";

    }

} else {

    $result="posts_ended";

}

header( 'Content-Type: application/json' );

die( json_encode( $result ) );

tech