Review code to prevent allowed memory limit issue

Question

While this may seem to be the right thing to do, I feel my code is very bad.

I'm running my Laravel 6.x app in a Docker container. When running the code below, I get

Allowed memory size of ** bytes exhausted (tried to allocate 8192 bytes)

No matter how high I set the memory_limit, it's the same error (with the new limit). So I want to review my code:

// I'm running a seeder.
$arr = [1,2,3,4,5,.....];

// Get all users and update a column:
$users = Users:all();

// Loop and update (we have thousands )
foreach ($users as $user) {
  $index = array_rand($arr);
  $user->someColumn = $arr[$index];
  $user->save();
}
// Another loop for another model with same as above.....

This is causing the "allowed memory" issue. Is there any better way to achieve this?

can you do this in database layer instead? of course you'll exhaust your memory if you iterate each and every user — Kevin, Jul 17 '20 at 08:17
What was the `memory_limit` you set? Does your system have enough RAM? — sykez, Jul 17 '20 at 08:18
Hi. What do you mean? Raw SQL? If so, how would I include the random item from the array? — Sylar, Jul 17 '20 at 08:19
@Sylar do you really need the seed in PHP layer?, if all can be done in db layer, the better. — Kevin, Jul 17 '20 at 08:27
@Kevin Could you show me an example how to include the array, select a random item from the array, should I do it in raw sql? linktoahref's method seems to be going just fine. SQL way seems more advance. — Sylar, Jul 17 '20 at 08:37
if your seeder can generate one by one, consider batch update user, may be 100 rows each time — Gavin Kwok, Jul 17 '20 at 08:43

linktoahref · Accepted Answer · 2020-07-17T08:09:20.623

2

Instead of fetching all users at once, fetch chunk of users

\App\User::chunk(10, function ($users) use ($arr) {
    foreach ($users as $user) {
        $index = array_rand($arr);
        $user->someColumn = $arr[$index];
        $user->save();
    }
});

edited Jul 17 '20 at 08:09

answered Jul 17 '20 at 08:05

linktoahref

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Thanks. I'll try this out and let you know. – Sylar Jul 17 '20 at 08:08

Review code to prevent allowed memory limit issue

1 Answers1