The syncWithoutDetaching method can cause excessive RAM consumption in large databases

[MohammadZarifiyan]

Laravel Version

11.32

PHP Version

8.1

Database Driver & Version

MySQL 8.0.31

Description

Using syncWithoutDetaching will cause a shortage of RAM in the system.

Steps To Reproduce

First create post_user pivot table and add 10 million rows to it. The run the following code:

$user = \App\Models\User::first();
$post = \App\Models\Post::first();

$user->posts()->syncWithoutDetaching([
  $post->getKey() => ['status' => 'pending']
]);

[marius-mcp]

I would suggest to use mass update instead of this for this case. Bear in mind it will not trigger events like that. So in conclusion I don't think this is a bug/issue.

[MohammadZarifiyan]

Laravel receives the rows in the pivot all at once and performs comparison operations. This is what causes the problem.