Laravel Eloquent内存泄漏重复检索相同的记录

我正在try 编写一个laravel函数，该函数从一个数据库获取大量记录(100,000+)，然后将其放入另一个数据库.为此，我需要查询我的数据库并查看该用户是否已经存在.我反复调用这个代码:

$users = User::where('id', '=', 2)->first();

然后，在这种情况发生几百次之后，我的记忆就耗尽了.所以，我做了一个极简主义的例子，它使用了所有可用的内存，看起来是这样的:

<?php

use Illuminate\Console\Command;

class memoryleak extends Command
{
    protected $name = 'command:memoryleak';
    protected $description = 'Demonstrates memory leak.';

    public function fire()
    {
        ini_set("memory_limit","12M");

        for ($i = 0; $i < 100000; $i++)
        {
            var_dump(memory_get_usage());
            $this->external_function();
        }
    }

    function external_function()
    {
        // Next line causes memory leak - comment out to compare to normal behavior
        $users = User::where('id', '=', 2)->first();

        unset($users);
        // User goes out of scope at the end of this function
    }
}

这个脚本的输出(由'php artisan command:memoryleak'执行)如下所示:

int(9298696)
int(9299816)
int(9300936)
int(9302048)
int(9303224)
int(9304368)
....
int(10927344)
int(10928432)
int(10929560)
int(10930664)
int(10931752)
int(10932832)
int(10933936)
int(10935072)
int(10936184)
int(10937320)
....
int(12181872)
int(12182992)
int(12184080)
int(12185192)
int(12186312)
int(12187424)
PHP Fatal error:  Allowed memory size of 12582912 bytes exhausted (tried to allocate 89 bytes) in /Volumes/Mac OS/www/test/vendor/laravel/framework/src/Illuminate/Database/Connection.php on line 275

If I comment out the line "$users = User::where('id', '=', 2)->first();" then the memory usage stays stable.

Does anyone have any insight as to why this line would use memory like this, or know a smarter way to accomplish what I am trying to do?

谢谢你抽出时间.