如何使用Laravel 5对来自自定义查询的结果进行分块

Question

Following up on this Question: How to chunk results from a custom query in Laravel

I try

DB::connection('mgnt')->select($query)->chunk(200, function($orders) {
    foreach ($orders as $order) { 

    //a bunch of code...

    }
});

But I get the following error:

FatalErrorException in MigrationController.php line 98:
 Call to a member function chunk() on array

Is chunking possible without having an appropriate Eloquent ORM Model? I try to chunk because I get a blank page (can't find any errrors in any log) if the query returns too many results.

I think right now it max 50.000 results that I can query at once. Is that maybe due to some restriction or limitation in Laravel?

Answer 1

Well since the query will just return an array of objects you can simply use PHP's array_chunk() :

$result = DB::connection('mgnt')->select($query);
foreach(array_chunk($result, 200) as $orders){
    foreach($orders as $order){
        // a bunch of code...
    }
}

---

Here's what chunk() on an eloquent model does:

$results = $this->forPage($page = 1, $count)->get();

while (count($results) > 0)
{
    // On each chunk result set, we will pass them to the callback and then let the
    // developer take care of everything within the callback, which allows us to
    // keep the memory low for spinning through large result sets for working.
    call_user_func($callback, $results);

    $page++;

    $results = $this->forPage($page, $count)->get();
}

You could try to do something similar (although I think it should be possible to run your query all at once, but I can't help you with that...)

1. Add a limit to your SQL query LIMIT 200
2. Increase the offset with every query you run. First 0, second 1 * 200, third 2 * 200
3. Do that until the result is returned empty (eg with a while loop like above)