PHP memory 在 For 循環中的使用不斷增長

Question

我有一個我運行的腳本，它執行了很多任務並且經歷了大約 21k 次。 問題是對於每個索引我都在做幾個不同的事情，每個索引都是我們數據庫中的一個產品，我通過從 API 獲取數據並保存產品等來更新價格。 我有幾個區域在幾乎每個方法調用之前和之后都調用了 memory_get_usage memory_get_usage() ，而且我所擁有的每個人似乎都增加了 memory。 沒有人比其他人做得更多，或者沒有那么引人注目。

我試圖取消設置循環底部的所有變量，並嘗試將它們設置為 null，但無論 memory 限制如何，每次迭代都會不斷提高。

我可以做些什么來清除這個 memory，我認為取消設置變量應該可以釋放 memory 但它似乎沒有這樣做？

編輯：我忘了提到我開始調查的原因是我在服務器上收到 memory 限制錯誤。 它並不總是在同一點發生，甚至每次運行時都會發生。 這就是我試圖調查它的原因。

該腳本需要大約一個小時才能運行，我在早上運行它，當時什么都沒有發生，現在它只在臨時服務器上，所以真的沒有人打服務器。

我可以發布代碼，但它相當大

<?php


if( !function_exists('memory_get_usage') ){
    include('function.php');
}
echo "At the start we're using (in bytes): ",
     memory_get_usage() , "\n\n";

$path = realpath(dirname(__FILE__) . '/../../../../Mage.php');
require_once($path);
Mage::app();
require_once '/lib/ProductUpdate.php';
echo "Starting product update process \n\n";
$productUpdate = new ProductUpdate();
$dealerStoreId = 3;
$volumeDiscountGroupId = 4;
$retailGroupId = Mage_Customer_Model_Group::CUST_GROUP_ALL;
$wholesaleGroupId = 2;


echo "Grabbing all products \n\n";
Mage::app()->setCurrentStore(Mage_Core_Model_App::ADMIN_STORE_ID);

// get the products from the InOrder stored procedure qty since datetime and don't pass a date to get all products, also pass the id of the cron job
$ioProducts = $productUpdate->getProductUpdateProducts('WEB2');
echo "---------------------------\n\n";
echo "Begin Updating Products \n\n";
echo "---------------------------\n\n";
$productCount = 0;
$productUpdate->saveScriptStarted(2);
echo "Before we go into the initial loop we are using (in bytes): ",
     memory_get_usage() , "\n\n";
foreach ($ioProducts as $ioProduct) {
    $updateProduct = false;
    $updateTierPrice = false;
    $sku = trim($ioProduct['inp_short_item_number']) . trim($ioProduct['isc_SIZE']) . trim($ioProduct['isc_COLOR']);
    echo "Checking item number " . $sku . " \n\n";
    echo "Before Loading Product " . $sku .  " we are using (in bytes): ",
     memory_get_usage() , "\n\n";
    $product = $productUpdate->getProduct();
    $productId = $product->getIdBySku($sku);
    echo "After Getting Id from sku " . $sku .  " we are using (in bytes): ",
     memory_get_usage() , "\n\n";
    if ($productId) {
        //$product = $productUpdate->getProduct()->load($productId);
        echo "After Loading Product " . $sku .  " we are using (in bytes): ",
            memory_get_usage() , "\n\n";
        echo "WE HAVE A PRODUCT!: " . $product->getName() . "\n\n";

        try {
            echo "Before Getting Additional Info from InOrder for Product " . $sku .  " we are using (in bytes): ",
            memory_get_usage() , "\n\n";

            // Since the product is same for parent products as it is for children you should just be able to get the price  of the parent and use that.
            $additionalInfo = $productUpdate->getItemDetails($ioProduct['inp_short_item_number'], 'WEB2');

            echo "After Getting Additional Info from InOrder for Product " . $sku .  " we are using (in bytes): ",
            memory_get_usage() , "\n\n";

            echo "Before Getting Extra Charges from InOrder for Product " . $sku .  " we are using (in bytes): ",
            memory_get_usage() , "\n\n";

            $oversizeCharge = $productUpdate->getExtraCharges($ioProduct['inp_short_item_number']);

            echo "After Getting Extra Charges from InOrder for Product " . $sku .  " we are using (in bytes): ",
            memory_get_usage() , "\n\n";
        } catch (Exception $e) {
            echo $e->getMessage() . "\n\n";
            continue;
        }

        if (is_array($additionalInfo) && count($additionalInfo) > 0) {
            if (isset($oversizeCharge[0]['Shipping Unit Charge']) && $product->getOversizeCharge() != $oversizeCharge[0]['Shipping Unit Charge']) {
                $product->setOversizeCharge($oversizeCharge[0]['Shipping Unit Charge']);
                $updateProduct = true;
                unset($oversizeCharge);
            }
            if ($product->getPrice() != $additionalInfo[0]['pri_current_price']) {
                $product->setPrice($additionalInfo[0]['pri_current_price']);
                $updateProduct = true;
                unset($additionalInfo);
            }
            echo "Before Setting Stock Status for Product " . $sku .  " we are using (in bytes): ",
            memory_get_usage() , "\n\n";

            $product = $productUpdate->setStockStatus($product, $ioProduct);

            echo "After Setting Stock Status for Product " . $sku .  " we are using (in bytes): ",
            memory_get_usage() , "\n\n";

            if ($product->getNeedsUpdate()) {
                $updateProduct = true;
            }

            if ($updateProduct) {
                try{
                    echo "Before Saving Product " . $sku .  " we are using (in bytes): ",
                    memory_get_usage() , "\n\n";

                   $productUpdate->saveProduct($product, $ioProduct);

                    echo "After Saving Product " . $sku .  " we are using (in bytes): ",
                    memory_get_usage() , "\n\n";
                }catch (Exception $e){
                    echo $e->getMessage() . "\n\n";
                    continue;
                }
            }


            // Go through  and do the same thing for the other 2 web classes to set pricing for the Dealer and Volume wholesale customers
            $updateProduct = false;
            try {
                echo "Before getting Tier Price info for " . $sku .  " we are using (in bytes): ",
                memory_get_usage() , "\n\n";

                $product = $productUpdate->getProduct()->setStoreId($dealerStoreId)->load($productId);
                $additionalInfo = $productUpdate->getItemDetails($ioProduct['inp_short_item_number'], 'WEB3');
                //$additionalTierInfo = $productUpdate->getItemDetails($ioProduct['inp_short_item_number'], 'WEB4');

                // Get Real Tier Prices based on Customer Type
                $retailPriceBreaks = $productUpdate->getItemPriceBreaks($ioProduct['inp_short_item_number'], Mage::getStoreConfig(Lancaster_InOrder_Helper_Data::XML_PATH_RETAIL_PRICE_LIST));
                $wholesalePriceBreaks = $productUpdate->getItemPriceBreaks($ioProduct['inp_short_item_number'], Mage::getStoreConfig(Lancaster_InOrder_Helper_Data::XML_PATH_WHOLESALE_PRICE_LIST));
                $volumeWholesalePriceBreaks = $productUpdate->getItemPriceBreaks($ioProduct['inp_short_item_number'], Mage::getStoreConfig(Lancaster_InOrder_Helper_Data::XML_PATH_VOLUME_WHOLESALE_PRICE_LIST));

                echo "After getting Tier Price infor for " . $sku .  " we are using (in bytes): ",
                memory_get_usage() , "\n\n";
            } catch (Exception $e) {
                echo $e->getMessage() . "\n\n";
                continue;
            }


            if ($product->getPrice() != $additionalInfo[0]['pri_current_price']) {
                $product->setPrice($additionalInfo[0]['pri_current_price']);
                $updateProduct = true;
            }

            //The only way to setup multiple price for one website is to set a tier price so we set it to a specific group and the dealer site then go through and set all the other real tier prices
            $tierPriceInfo = $product->getData('tier_price');
            if (!empty($tierPriceInfo)) {
                echo "Before looping through Tier Price infor for " . $sku .  " we are using (in bytes): ",
                memory_get_usage() , "\n\n";
                foreach ($tierPriceInfo as $tierPrice) {
                    if ($tierPrice["website_id"] == $dealerStoreId &&
                        $tierPrice["cust_group"] == $volumeDiscountGroupId &&
                        $tierPrice["price_qty"] == '1' &&
                        $tierPrice["price"] != $additionalTierInfo[0]['pri_current_price']) {
                        $updateTierPrice = true;
                    }
                    //todo need to do some refinement to the following, was rushed to put out the logic need to fix so it doesn't update everytime
                    // need to find if any of the tier prices do not match price as well if there is a price break in InOrder but not in Magento

                    if (!$updateTierPrice ) {

                        $updateRetail = isUpdateTierPrices($retailPriceBreaks, $tierPrice, $retailGroupId);
                        $updateWholesale = isUpdateTierPrices($wholesalePriceBreaks, $tierPrice, $wholesaleGroupId);
                        $updateVolWholesale = isUpdateTierPrices($volumeWholesalePriceBreaks, $tierPrice, $volumeDiscountGroupId);
                        if (
                            (count($retailPriceBreaks) > 0 && !$updateRetail['priceTierExists']) &&
                            (count($wholesalePriceBreaks) > 0 && !$updateWholesale['priceTierExists']) &&
                            (count($volumeWholesalePriceBreaks) > 0 && !$updateVolWholesale['priceTierExists'])) {
                             $updateTierPrice = true;
                        }

                        if(($updateRetail['updateTierPrice'] || $updateWholesale['updateTierPrice'] || $updateVolWholesale['updateTierPrice'])){
                            $updateTierPrice = true;
                        }
                    }
                }
                unset($tierPriceInfo);
                echo "After looping through Tier Price infor for " . $sku .  " we are using (in bytes): ",
                memory_get_usage() , "\n\n";
            }
            else {
                $updateTierPrice = true;
            }
            if ($updateTierPrice) {
                echo "Before setting whether we update Tier Price for " . $sku .  " we are using (in bytes): ",
                memory_get_usage() , "\n\n";
                //construct the tier price
                $website_id = Mage::getModel('core/store')->load($dealerStoreId)->getWebsiteId();
                $tierPrices = array(array(
                                        'website_id' => $website_id,
                                        'cust_group' => $volumeDiscountGroupId,
                                        'price_qty' => '1',
                                        'price' => $additionalTierInfo[0]['pri_current_price']
                                    ));

                updateTierPrices($retailPriceBreaks, $retailGroupId, $tierPrices);
                updateTierPrices($wholesalePriceBreaks, $wholesaleGroupId, $tierPrices);
                updateTierPrices($volumeWholesalePriceBreaks, $volumeDiscountGroupId, $tierPrices);

                $product->setData('tier_price', $tierPrices);
                $updateProduct = true;
                unset($website_id);
                echo "After setting whether we update Tier Price for " . $sku .  " we are using (in bytes): ",
                memory_get_usage() , "\n\n";
            }

            if ($updateProduct) {
                try{
                     echo "Before saving product for Tiered Pricing for " . $sku .  " we are using (in bytes): ",
                    memory_get_usage() , "\n\n";
                  // $productUpdate->saveProduct($product, $ioProduct);
                    echo "After saving product for Tiered Pricing for " . $sku .  " we are using (in bytes): ",
                    memory_get_usage() , "\n\n";
                }catch (Exception $e){
                    echo $e->getMessage() . "\n\n";
                    continue;
                }

            }
        }
    }
    $retailPriceBreaks = null;
    $wholesalePriceBreaks = null;
    $volumeWholesalePriceBreaks = null;
    $oversizeCharge = null;
    $additionalTierInfo = null;
    $additionalInfo = null;
    $product = null;
    $productCount++;
    echo $productCount . " Products have been proceessed \n\n";
}
echo "After running through all products we are using (in bytes): ",
                    memory_get_usage() , "\n\n";
echo "Peak memory usage for product update scrip (in bytes): ",
                    memory_get_peak_usage() , "\n\n";

Answer 1

在 PHP 中增加 memory 的使用是正常的。 取消設置變量不會立即釋放它所占用的 memory，它只是將其標記為可重復使用。 在某個時候，PHP 會決定應該運行垃圾收集器，這就是真正釋放 memory 的時候。

除非你真的遇到了“內存不足”的致命錯誤，否則這沒什么好擔心的。 PHP 盡最大努力防止 OOM 發生，但它不會在每次取消設置變量時都運行非常昂貴的垃圾收集。 如果發生這種情況，性能實際上會陷入停頓。

Answer 2

在沒有看到您的代碼的情況下，我的猜測是 PHP 的垃圾收集（釋放未使用的內存）沒有在您的腳本運行時運行。

故事的重點，這種行為是可以接受和預期的。 只要你沒有得到任何 memory 錯誤，你應該沒事。