Eloquent chunk() missing half the results

Question

I have a problem with Laravel\'s ORM Eloquent chunk() method. It misses some results. Here is a test query :

$destinataires = Destinataire::where(\'statut\', \'&         


        

Answer 1

Imagine you are using chunk method to delete all of the records. The table has 2,000,000 records and you are going to delete all of them by 1000 chunks.

$query->orderBy('id')->chunk(1000, function ($items) {
    foreach($items as $item) {
        $item->delete();
    }
});

It will delete the first 1000 records by getting first 1000 records in a query like this:

SELECT * FROM table ORDER BY id LIMIT 0,1000

And then the other query from chunk method is:

SELECT * FROM table ORDER BY id LIMIT 1000,2000

Our problem is here, that we delete 1000 records and then getting results from 1000 to 2000. Actually we are missing first 1000 records and this means that we are not going to delete 1000 records in first step of chunk! This scenario will be the same for other steps. In each step we are going to miss 1000 records and this is the reason that we are not getting best result in these situations.

I made an example for deletion because this way we could know the exact behavior of chunk method.

---

UPDATE:

You can use chunkById() for deleting safely.

Read more here:

http://laravel.at.jeffsbox.eu/laravel-5-eloquent-builder-chunk-chunkbyid https://laravel.com/api/5.4/Illuminate/Database/Eloquent/Builder.html#method_chunkById