Query is not work.

I use this codes in my functions.php to track post views.

/* Functions to track Post Views*/
 function getPostViews($postID){
 $count_key = 'post_views';
 $count = get_post_meta($postID, $count_key, true);
 if($count==''){
    delete_post_meta($postID, $count_key);
    add_post_meta($postID, $count_key, '0');
    return "0 View";
}
return $count.' view';
 }
 function setPostViews($postID) {
 $count_key = 'post_views';
 $count = get_post_meta($postID, $count_key, true);
 if($count==''){
    $count = 0;
    delete_post_meta($postID, $count_key);
    add_post_meta($postID, $count_key, '0');
}else{
    $count++;
    update_post_meta($postID, $count_key, $count);
 }
 }

 /* Track the Views for the post using wp_head hook */
 function trackPostViews ($post_id) {
 if ( !is_single() ) return;
 if ( empty ( $post_id) ) {
    global $post;
    $post_id = $post->ID;
 }
 setPostViews($post_id);
 }
 add_action( 'wp_head', 'trackPostViews');

In the admin area is all ok. Function is works fine and write post views to database.
But i want to display my most viewed post on the sidebar and it is not work. There is dispalyed posts, but not most viewed. This is my query.

<?php

 function filter_where2($where = '') {
 $where .= " AND post_date > '" . date('Y-m-d', strtotime('-10 days')) . "'";
 return $where;
 }
 if ( ! $my_paged = absint( get_query_var( 'paged' ) ) )
 $my_paged = 1;

 if ( ! $my_query = get_transient( "7677recent_$my_paged" ) ) 

 {
add_filter('posts_where', 'filter_where2');
$my_query = new WP_Query( "meta_key=post_views&orderby=meta_value&order=DESC&posts_per_page=5&paged=$my_paged" );
set_transient( "7677recent_$my_paged", $my_query, 60 * 60 );
 }
 remove_filter( 'posts_where', 'filter_where2' );
 while ($my_query->have_posts()) : $my_query->the_post();
 ?>

I just can`t understand why it is not work. This is a big puzzle for me.