Wp-Admin search by meta value

plugin-name.php

<?php
/**
 * Plugin Name: Search By Meta
 * Plugin URI: http://wordpress.stackexchange.com/questions/11758/extending-the-search-context-in-the-admin-list-post-screen
 * Description: SearchByMeta.
 * Author: SearchByMeta
 * Author URI: http://wordpress.stackexchange.com/questions/11758/extending-the-search-context-in-the-admin-list-post-screen
**/


add_filter('posts_join', 'catalog_product_search_join' );
function catalog_product_search_join ($join){
    global $pagenow, $wpdb;
    // I want the filter only when performing a search on edit page of Custom Post Type named "catalog_product"
    if ( is_admin() && $pagenow=='edit.php' && $_GET['post_type']=='catalog_product' && $_GET['s'] != '') {
        $join .='LEFT JOIN '.$wpdb->postmeta. ' ON '. $wpdb->posts . '.ID = ' . $wpdb->postmeta . '.post_id ';
    }
    return $join;
}

add_filter( 'posts_where', 'catalog_product_search_where' );
function catalog_product_search_where( $where ){
    global $pagenow, $wpdb;
    // I want the filter only when performing a search on edit page of Custom Post Type named "catalog_product"
    if ( is_admin() && $pagenow=='edit.php' && $_GET['post_type']=='catalog_product' && $_GET['s'] != '') {
        $where = preg_replace(
       "/\(\s*".$wpdb->posts.".post_title\s+LIKE\s*(\'[^\']+\')\s*\)/",
       "(".$wpdb->posts.".post_title LIKE $1) OR (".$wpdb->postmeta.".meta_value LIKE $1)", $where );
    }
    return $where;
}

function catalog_product_search_distinct( $where ){
    global $pagenow, $wpdb;

    if ( is_admin() && $pagenow=='edit.php' && $_GET['post_type']=='catalog_product' && $_GET['s'] != '') {
    return "DISTINCT";

    }
    return $where;
}
add_filter( 'posts_distinct', 'catalog_product_search_distinct' );

Credits for the awnsers in http://wordpress.stackexchange.com/questions/11758/extending-the-search-context-in-the-admin-list-post-screen