How to Optimize Your WordPress Metadata

class-page-object.php

<?php

class Page_Object {
    public $ID;

    public $original_post;

    public $data = array();

    public function __construct( $id ) {

    	if ( $id <= 0 || !is_int( $id ) ) {
    		return false;
    	}

        $this->original_post = get_post( $id );

        $this->ID = $this->original_post->ID;

        add_filter( 'get_post_metadata', array( $this, 'get_meta' ), -1, 4 );

        add_filter( 'update_post_metadata', array( $this, 'update_meta' ), -1, 5 );

        add_action( 'shutdown', array( $this, 'sync_data' ) );
    }

    public function get_meta( $value, $page_id, $meta_key, $single ) {

    	if ( $page_id != $this->ID ) {
    		return $value;
    	}

    	if ( !array_key_exists( $meta_key, $this->data ) ) {
	        remove_filter( 'get_post_metadata', array( $this, 'get_meta' ), -1, 4 );

    		$this->data[ $meta_key ] = get_metadata( 'post', $this->ID, $meta_key, false );

	        add_filter( 'get_post_metadata', array( $this, 'get_meta' ), -1, 4 );
    	} elseif ( !$meta_key ) {
    		$this->data = get_metadata( 'post', $this->ID );
    	}

		$value = $this->data[ $meta_key ];

    	if ( $single && is_array( $value ) ) {
			return $value[0];
    	} else {
			return $value;
    	}
    }

    public function update_meta( $value, $page_id, $meta_key, $meta_value, $prev_value ) {

    	if ( $page_id != $this->ID ) {
    		return $value;
    	}

    	$this->data[ $meta_key ] = $meta_value;

    	return true;
    }

    public function sync_data() {
        remove_filter( 'update_post_metadata', array( $this, 'update_meta' ), -1, 5 );

    	foreach ( $this->data as $meta_key => $meta_value ) {
    		update_metadata( 'post', $this->ID, $meta_key, $meta_value );
    	}
    	
        add_filter( 'update_post_metadata', array( $this, 'update_meta' ), -1, 5 );
    }
}

wcfay.php

<?php
/*
Plugin Name: WCFay 2014
Description: Organizing and optimizing custom metadata.
Plugin URI: http://wcfay.com
Author: A. Tate Barber
Author URI: http://tatemz.com
Version: 1.0
*/

class WCFay {
	public function __construct() {

		// Register install function to create our tables
		register_activation_hook( __FILE__, array( $this, 'create_meta_tables' ) );

		// init our plugin
		add_action( 'init', array( $this, 'init' ) );

		// filter our content to show session meta
		add_filter( 'the_content', array( $this, 'display_sessionmeta' ) );
	}

	public function init() {
		global $wpdb;

		// Add our new tables to the $wpdb
		$wpdb->sessions = $wpdb->prefix . 'sessions';
		$wpdb->tables[] = 'sessions';

		$wpdb->sessionmeta = $wpdb->prefix . 'sessionmeta';
		$wpdb->tables[] = 'sessionmeta';
	}

	public function create_meta_tables() {
		global $wpdb;

		$collate = '';

		// Prepare dbDelta to create some meta tables!
		require_once( ABSPATH . 'wp-admin/includes/upgrade.php' );

		// set $collate...
		if ( $wpdb->has_cap( 'collation' ) ) {
			if ( ! empty($wpdb->charset ) ) {
				$collate .= "DEFAULT CHARACTER SET $wpdb->charset";
			}
			if ( ! empty($wpdb->collate ) ) {
				$collate .= " COLLATE $wpdb->collate";
			}
		}

		// create table mysql query
		$new_tables = "
		CREATE TABLE {$wpdb->prefix}sessions (
		  session_id bigint(20) NOT NULL auto_increment,
		  session_name longtext NOT NULL DEFAULT '',
		  session_speaker longtext NOT NULL DEFAULT '',
		  PRIMARY KEY  (session_id)
		) $collate;
		CREATE TABLE {$wpdb->prefix}sessionmeta (
		  meta_id bigint(20) NOT NULL auto_increment,
		  session_id bigint(20) NOT NULL,
		  meta_key varchar(255) NULL,
		  meta_value longtext NULL,
		  PRIMARY KEY  (meta_id),
		  KEY session_id (session_id),
		  KEY meta_key (meta_key)
		) $collate;";

		// Run that query
		dbDelta( $new_tables );
	}

	public function get_session( $id = 0 ) {
		global $wpdb;

		if ( $id <= 0 ) {
			return false;
		}

		// Get our session from the database
		$session = $wpdb->get_row( $wpdb->prepare( "
			SELECT 		*
			FROM 		{$wpdb->sessions}
			WHERE 		session_id = %d
		", $id ) );

		return $session;
	}

	public function display_sessionmeta( $content ) {

		// Only modify this page's content
		if ( get_the_title() == 'How to Optimize Your WordPress Metadata' ) {

			// There's probably a better way to get the session_id ... post_meta?
			$session_id = 1;

			// Get the session
			$session = $this->get_session( $session_id );

			// Get the session metadata
			$session_meta = get_metadata( 'session', $session_id );

			if ( $session_meta ) {
				$content .= '<table><thead><th>meta_key</th><th>meta_value</th></thead><tbody>';

				// Add our metadata to a display table
				foreach ( $session_meta as $meta_key => $meta_value ) {
					$content .= sprintf( '<tr><td>%s</td><td>%s</td></tr>', $meta_key, $meta_value[0] );
				}

				$content .= '</tbody></table>';
			}
		}

		$this->test_meta_optimization();

		// Return the original or modified content
		return $content;
	}

	public function test_meta_optimization() {

		include_once( 'class-page-object.php' );

		$entries = 3000;

		$our_optimal_page = new Page_Object( get_the_id() );

		$id = get_the_id();
		// $id = $our_optimal_page->ID;

		$time_start = microtime( true );

		for ( $i = 0; $i < $entries ; $i++ ) { 
			update_post_meta( $id, '_wcfay_meta_' . $i, 'optimized-GOOD' );
		}

		$time_end = microtime( true );
		$time = $time_end - $time_start;

		d( 'Update ' . $entries . ' meta data entries: ' . $time );
	}
}

$GLOBALS['wcfay'] = new WCFay;