Optimising a script to scan files in a folder - php

Question

I have my folder /images (with ~ 95.000 files), and i check every file if is in the database.
Table : images
Row : hash
The folder containt all my image with sha1 name.
I use shuffle($images); to make sure the verification is random, otherwise it only verifies the first 35,000 images.
If I go over 35,000 checks, the script puts a timeout and the page blocks it.
Example name of an image : d0a0bb3149bea2335e8784812fef706ad0a13156.jpg
My Script :
I select the images in the database
I'm putting it in a array
I make the array random (to avoid always checking the first 35,000
images)
I create a array of images file in the folder /images
I check for missing database files using the array created by the
opendir(); function
I display the answer
<?php
set_time_limit(0);
$images = [];
$q = $mysqli->query('SELECT hash FROM images');
while($r = $q->fetch_assoc())
{
$images[] = $r['hash'].'.jpg';
}
shuffle($images);
$i_hors_bdd = 0;
$images_existent_hors_bdd = [];
if($dh = opendir($_SERVER['DOCUMENT_ROOT'].'/images'))
{
while(($file = readdir($dh)) !== false)
{
if(!in_array($file, $fichiers_a_exclures))
{
if(!is_sha1($file) OR !in_array($file, $images))
$images_existent_hors_bdd[] = '<p>Name of File: '.$file.'</p>';
}
if($i_hors_bdd > 35000)
{
break;
}
$i_hors_bdd++;
}
}
closedir($dh);
if(count($images_existent_hors_bdd) > 0)
{
echo '<p>Image exist, but not in the databse.</p>';
sort($images_existent_hors_bdd);
foreach($images_existent_hors_bdd as $image_existe_hors_bdd)
echo $image_existe_hors_bdd;
}
else
echo '<p>All images are in datase.</p>';
echo '<p>'.$i_hors_bdd.' images checked.</p>';
So my question is: How can I optimize this script to improve the speed of the script to allow checking more images without blocking the script? Knowing that my VPS is not very powerful and I don't have SSD.

Answer 1

Here are some things to consider or try:
Concatenate '.jpg' to hash in the sql, then use fetch_all into a numeric array.
use scandir to build an array of files in the directory
use array_diff to remove $fichiers_a_exclures and $images
iterate over this smallest array to do the sha1 test