使用大型数据库时，Ajax请求需要很长时间才能完成

Question

I am working on a website written in Yii framework (version 1.1.14) that allows uploading and displaying news. The admin of the site can select three news to promote to homepage and specify the order in which they are displayed. I am using Mysql database. The news table has two fields: isChecked (0 or 1) and homepagePos (integer) in addition to the other fields. The isChecked field determines whether the news is selected for displaying in homepage and the homepagePos field determines the order in which the news are displayed. I have used jquery's sortable plugin to sort the news. When the user selects which news to display and clicks save button, the news ids are sent to php via ajax.

The javascript portion to send the values to news controller is as follows:

$(document).on('click', '#saveToHomepage', function() 
{
    var url = ajaxRequestSendUrl;   //ajaxRequestSendUrl contains url to news controller's promote to homepage method.
    $.ajax({
        method: "GET",
        url: url,
        data: {
            contentIds: contentIds, //contentIds contains an array of news Ids in certain order
            },
        success: function() {
        // Show success message
        },
        error: function() {
            alert('Some error occured. Please reload the page and try again.');
        }
    });
});

Here's the promote to homepage method in news controller:

public function actionHomepage()
{
    $allNews = News::model()->findAll();
    $value = $_GET['contentIds'];
    foreach ($allNews as $news) {
        if($news->id == $value[0] ||$news->id == $value[1] ||$news->id == $value[2])
        {
            $news->isChecked = 1;
            $news->homepagePos = array_search($news->id, $value); //Assign index of the array as the position
            $news->save();
        }
        else
        {
            $news->isChecked = 0;
            $news->homepagePos = -1;
            $news->save();
        }
    }
}

My problem is that the news table I have has over 2k data. So the ajax call takes really long time (over a minute) to complete. Is there any way I can optimize the code or is there other way I can approach this to reduce the time taken to complete this operation? Thanks in advance

Answer 1

i am not sure, but why don't you get the filtered records from the database itself by sending the id's of selected news. I don't know your backend language. Seems, you are getting all the records and applying filtering. which consumes time. Instead get the filtered news from the database.

Hope this helps!

Answer 2

Its taking a long time because you're fetching all the records and then updating those three id . You could try this:

$criteria = new CDbCriteria;
$criteria->addInCondition( "id" , $value ) ; // $value = array ( 1, 2, 3 );
News::model()->updateAll(array('isChecked'=>'1','homepagePos'=>'val2'), $criteria);

You could do an update before hand to reset all the homepagePos and then update only the ids you need.

Answer 3

Three queries: One first to set the whole table to not checked status, and the rest to set the checked status only in the row each selected id

public function actionHomepage()
{
    $values = $_GET['contentIds'];
    $sql = "UPDATE news SET idChecked=0,homepagePos = -1";
    Yii::app()->db
        ->createCommand($sql)
        ->execute();
    for($ii = 0; $ii < 3; $ii++) {
        $sql = "UPDATE news SET idChecked = 1,homepagePos = ':homepagePos' WHERE id=:id";
        Yii::app()->db
            ->createCommand($sql)
            ->bindValues(array(':homepagePos' => array_search($ii, $values), ':id' => $values[$ii]))
            ->execute();
    }
}