php - 每次循环后内存使用量增加

Question

我有一个 foreach 循环，读取一个包含大约 200000 行的文件，这是我的 PHP:

foreach ($this->file as $row)
      {
        if ($this->file->valid())
        {

          //init client array
          $this->initInvoicesArray($row);
          $this->prepareInvoice();
          $row = null;
          $this->key = $this->file->key();

          //add msisdn to msisdn array, and client to clients array
          self::$MsisdnArray[] = $this->msisdn;
          self::$InvoicesArray[$this->msisdn] = $this->client;

          if ($i % 3000 == 0) 
          {
            //get valid users from table
            $this->prepareAndSaveValidClients();
          }

          $i++;
        }
      }

这是 prepareAndSaveValidClients() 函数:

public function prepareAndSaveValidClients(){
    $query = Doctrine_Query::create()
        ->select('p.gender, p.email2, u.username, u.first_name, u.last_name, u.email_address, u.is_active, p.msisdn, p.user_id, p.city_id, p.street, p.zipcode, p.msisdn_status')
        ->from('sfGuardUser u')
        ->innerJoin('u.Profile as p ON u.id = p.user_id')
        ->whereIn('p.msisdn', self::$MsisdnArray)
        ->whereIn('p.status', self::$AllowedStatus);

    $results = $query->fetchArray();

    //instanciat an object collection for payment_notifications
    $collection = new Doctrine_Collection("payment_notifications");

    if (!empty($results))
    {
      foreach ($results as $key => $client)
      {
        $invoice = self::$InvoicesArray[$client['Profile']['msisdn']];

        $this->initInvoicesArray($invoice);
        $this->prepareInvoice();

        $this->prepareUserProfile($client);
        $this->prepareClient();

        $paymentNotifications = new paymentNotifications();
        $paymentNotifications->fromArray($this->client);

        $collection->add($paymentNotifications);

        $tel = $client['Profile']['msisdn'];
        $client = null;
      }

      $collection->save();

      //clear memory
      $results = null;
      $collection = null;
      self::$MsisdnArray = null;
      self::$InvoicesArray = null;


      $this->logSection('tel num', 'added :' . $tel . ' Memory usage : ' . memory_get_usage());
      $duration = microtime(true) - $this->startTime;
      $this->logSection('payment : ', sprintf('added in %s', $duration));
    }
  }

至于功能:

   $this->initInvoicesArray($invoice);
   $this->prepareInvoice();

   $this->prepareUserProfile($client);
   $this->prepareClient();

它们只是为了准备$this->client

这是为每个循环显示的内存使用情况:

>> tel num   added :0699946185 Memory usage : 89287596
>> payment :  added in 8.6373870372772
>> tel num   added :0699983919 Memory usage : 165854544
>> payment :  added in 18.373502969742
>> tel num   added :0699949623 Memory usage : 241338788
>> payment :  added in 29.336947917938
>> tel num   added :0699854750 Memory usage : 319173092
>> payment :  added in 40.880628824234

如您所见，我尝试释放这些变量的内存:

$results = null;
$collection = null;
self::$MsisdnArray = null;
self::$InvoicesArray = null;

但徒劳无功，内存使用量在每次循环后不断增加，这导致了一个 Allowed Memory size exausted fatal error 。我该如何优化它？

谢谢。

Answer 1

Doctrine 对象具有 php 难以释放的循环引用。为了解决这个问题，doctrine 提供了 free() 方法，在设置为 null 之前在集合上调用它:

$collection->free(true);
$collection = null;