缓存mysql结果后PHP速度低

Question

after caching mysql result my web page lower to load page, i'm testing on firebug and get any result for after and before cache result, when i dont use cache my page can fast load ,

PHP:

<?php
@session_start();
$filename = '../cache/cache.dump';
$AND = $WHERE = NULL;
if ( isset( $_SESSION['portal_ID'] )) {
    $AND   = " AND contents.portal = {$_SESSION['portal_ID']}";
    $WHERE = " WHERE portal = {$_SESSION['portal_ID']}";
}

// ------------------ CACHE MYSQL RESULTS ----------------
if (filemtime($filename) < time()-24*3600) { 
    $getTopics=$db->loadAssoc($db->setQuery("SELECT * ,  categories.title AS category_title, 
                                            status_topics.title as status_topic
                                            FROM contents
                                            JOIN categories ON categories.id = contents.category
                                            JOIN status_topics ON status_topics.id = contents.status 
                                            $AND"));
    $getCategories           = $db->loadAssoc($db->setQuery("SELECT * FROM categories $WHERE"));
    $getAllCategories        = $db->loadAssoc($db->setQuery("SELECT * FROM categories $WHERE"));
    $getTags                 = $db->loadAssoc($db->setQuery("SELECT * FROM tags $WHERE"));
    $getAllTags              = $db->loadAssoc($db->setQuery("SELECT * FROM tags "));
    $getStatusTopics         = $db->loadAssoc($db->setQuery("SELECT * FROM status_topics"));
    $getPages                = $db->loadAssoc($db->setQuery("SELECT * FROM pages $WHERE"));
    $getSiteInformation      = $db->loadRow  ($db->setQuery("SELECT * FROM settings $WHERE"));
    $getSubDomainInformation = $db->loadAssoc($db->setQuery("SELECT * FROM sub_domains"));
    $getUserInformation      = $db->loadAssoc($db->setQuery("SELECT * FROM users $WHERE"));
    $getActiveSubDomains     = $db->loadAssoc($db->setQuery("SELECT * FROM sub_domains WHERE  subdomain_active = 1"));
    $getDeactiveSubDomains   = $db->loadAssoc($db->setQuery("SELECT * FROM sub_domains WHERE  subdomain_active = 0"));
    $getUser_information=$db->loadRow($db->setQuery("SELECT * FROM users JOIN permissions on permissions.id = users.permission WHERE username = '{$_SESSION['username']}'"));
    file_put_contents($filename, serialize(
        array(
                $getTopics,
                $getCategories, 
                $getAllCategories,
                $getTags,
                $getAllTags,
                $getStatusTopics,
                $getPages,
                $getSiteInformation,
                $getSubDomainInformation,
                $getUserInformation,
                $getActiveSubDomains,
                $getDeactiveSubDomains,
                $getUser_information
            ))); 
} 
// ------------------READ FROM CACHE MYSQL RESULTS ----------------
else 
{
  $data = unserialize(file_get_contents($filename));
  list(
        $getTopics,
        $getCategories, 
        $getAllCategories,
        $getTags,
        $getAllTags,
        $getStatusTopics,
        $getPages,
        $getSiteInformation,
        $getSubDomainInformation,
        $getUserInformation,
        $getActiveSubDomains,
        $getDeactiveSubDomains,
        $getUser_information
      ) = $data;
}

//print_r($WHERE);

?>

firebug result in screenshots:

after cache before cache

cache.dump file size is 7kb

Answer 1

Looks like approach you choose is quite wrong.

Your code is trying to sit on someone's else place. Database is for storing data.
PHP is for retrieving and format it.

Just do not duplicate your database with homebrewed cache. Database has it's own and it's blazingly fast.

So, just get rid of this "cache" and go for the common way - on the every page select the only data required on this very page. That's all

Answer 2

You could use var_export() rather than serialize . I think this will improve the performance .