Question

I have the function below which I call very frequently in a loop.

I waited 5 minutes as the memory climbed up from 1MB to 156MB. Should’t PHP’s garabage collector turn up and reduce this at some point?!

Is it because I have set memory limit at 256MB?

At echo point 2,3,4 its pretty constant memory usage. It goes down my half a meg at point 4. But point 1 is where the main memory increase happens. Probably because of file_get_html loading the html file in memory.

I though the clear and unset of the variable $html would take care of this?

function get_stuff($link, $category ){

    $html = file_get_html(trim("$link"));

    $article = $html->find('div[class=searchresultsWidget]', 0);

    echo '1 - > '.convert(memory_get_usage(true)).'<br />';  

    foreach($article->find('h4 a') as $link){

        $next_url = 'http://new.mysite.com'.$link->href;

        $font_name = trim($link->plaintext);        

        $html = file_get_html(trim("$next_url"));

        $article = $html->find('form[class=addtags]', 0);

        $font_tags = '';

        foreach($article->find('ul[class=everyone_tags] li a span') as $link){

            $font_tags .= trim($link->innertext).',';   

        }

        echo '2 - > '.convert(memory_get_usage(true)).'<br />'; 

        $font_name = mysql_real_escape_string($font_name);
        $category =  mysql_real_escape_string($category);  
        $font_tags = mysql_real_escape_string($font_tags);  

        $sql = "INSERT INTO tag_data (font_name, category, tags) VALUES ('$font_name', '$category', '$font_tags')";

        unset($font_tags);
        unset($font_name);
        unset($category); 

        $html->clear();   

        mysql_query($sql); 

        unset($sql);   

        echo '3 - > '.convert(memory_get_usage(true)).'<br />';    

} 

    unset($next_url);
    unset($link);
    $html->clear(); 
    unset($html);   
    unset($article);

    echo '4 - > '.convert(memory_get_usage(true)).'<br />';

}

As you can see, I attempted to make use of unset feebly. Although its no good as I understand it won’t “unset” memory as soon as I call it.

Thanks all for any help on how I can reduce this upward rise of memory.

Answer 1

There’s a known memory leak with file_get_html(): http://simplehtmldom.sourceforge.net/manual_faq.htm#memory_leak

The solution is to use

$html->clear();

Which you are doing, BUT: You’re using $html both inside and outside of the loop. Inside the loop you are calling $html->clear(), and then near the end of your function $html->clear() again (I assume to catch your initial file_get_html() object reference). That last call doesn’t do anything. You’re leaking memory with the initial $html = file_get_html() call.

Try using a different variable ($html1, maybe?) inside your loop and see what happens.