This is an incredibly scary result; blog.stackoverflow.com is getting, at best, a moderate trickle of incoming traffic. It’s barely linked anywhere! With that kind of CPU load level, this site would fall over instantaneously if it got remotely popular, or God forbid, anywhere near the front page of a social bookmarking website.

He then shows an image of how the blog’s CPU usage looked after installing the above-mentioned caching plugins. The improvement is tremendous, and he explains why he can’t understand why this type of caching isn’t built in to WordPress:

It’s not like this a new issue. Personally, I think it’s absolutely irresponsible that WP-Cache like functionality isn’t already built into WordPress. I would not even consider deploying WordPress anywhere without it. And yet, according to a recent podcast, Matt Mullenweg dismisses it out of hand and hand-wavingly alludes to vague TechCrunch server reconfigurations.

A default WordPress install will query the database twenty times every time you refresh the page, even if not one single element on that page has changed. Doesn’t that strike you as a bad idea? Maybe even, dare I say it, sloppy programming?

And it’s not like he’s setting higher standards for WordPress – he happily uses Movable Type which features static rendering, and he says that the .NET framework has had caching built in for years.

The point: install a caching plugin ASAP if you have not yet done so, and save yourself the problems of a sluggish, overweight site.

[This post is in honor of the current Pessach (Passover) season, a Jewish holiday where we clean our houses frantically in the hope that not one crumb of leavened bread (i.e. regular bread) be found during the 7 day holiday. This post is the WordPress version of Pessach cleaning, where cluttered databases are equivalent to leavened bread, etc. Happy Pessach!]

Define goals and create benchmarks:

1. First, define a goal, such as reducing page load time from 8 seconds to 2 seconds.
2. Measure your initial state and the results of each modification so that you can quantify any improvement. Test your site’s speed with the Website Speed Test, but do multiple tests since the results can be inaccurate due to fluctuations in your internet connection and other factors.
3. Use Pingdom to get a detailed analysis of your blog’s loading time and performance.
4. See what your browser is doing with tools like Firebug’s network tool, Charles Proxy or Wireshark, and review the server logs.
5. YSlow – analyzes web pages and tells you why they’re slow based on the rules for high performance web sites. YSlow is a Firefox add-on integrated with Firebug. See this presentation from Yahoo! that covers their latest research results and performance breakthroughs. It covers their existing 14 rules, plus 20 new rules for faster web pages. They’ve categorized the optimizations into: server, content, cookie, JavaScript, CSS, images, and mobile.

    

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Reduce the number of dynamic PHP and http calls:

1. “There is an inherent overhead in each HTTP request. It takes substantially less time to serve one 30K file than it does three 10K files.” So combine all files in a type into a library. Learn how here.
2. Use different host names to increase the number of active download threads.
3. Minimize PHP and database queries – Each time a page on your site loads, if your browser has to execute any PHP queries, it adds to the load time. If you replace the PHP queries with static HTML, every time a page loads, your browser just reads the HTML. An example from WP Candy:
   With PHP requests: <title><?php bloginfo(’name’); ?><?php bloginfo(’description’); ?></title>
   Without PHP requests: <title>WPCandy - The Best of WordPress</title>
Joost de Valk says that you can remove 11 queries to the database by doing the following in your header.php and footer.php files:

   • making your stylesheet URL’s static
   • making your pingback URL static
   • making your feed URLs static
   • removing the blog’s WordPress version
   • making your blog’s name and tagline / description staticSee more examples of how you can replace code in your WordPress template files with static HTML here and here.
4. Check if you have too many external calls to things like Amazon, eBay, MyBlogLog, etc. Try commenting them out one by one to see if it speeds things up.

Optimize your files: CSS, HTML, Javascript, images, video

1. Optimize your image files for the web.
2. Make sure that all images have height and width tags.
3. Consider hosting your images on an external site like flickr that has huge servers and can handle the load.
4. Use CSS sprites for static web images. CSS sprites are where the images are added to one larger image file, and laid out in a convenient way. Here’s a CSS Sprites generator.
5. Do not host videos on your server. Upload them to YouTube, Google Video, or any other video sharing site and let them handle the server load.
6. Compress your Javascript, using a tool or by removing formatting (and potentially by shortening function and variable names). This can reduce file size by 60%. Add gzip compression to that as well and you’re looking at a serious size reduction.
7. Compress HTML and CSS by removing HTML formatting, white space (where you divide code among separate lines for easier readability), trimming class names, omitting unambiguous quotes around attributes, etc.
8. Compress your CSS with the CSS Compress WordPress plugin – Automatically removes comments, new lines, tabs, and gzip compresses (GZIP) any CSS file called with “<?php bloginfo(’stylesheet_url’); ?>” Just activating the plugin with the default Kubrick theme will reduce the CSS file from 8k to 1.7k.
9. Compress your CSS by using shorthand CSS. Here’s an example from WP Candy:
   Long: .test {margin-top: 7px; margin-right: 1px; margin-bottom: 5px; margin-left: 3px;}
Short: .test {margin: 7px 1px 5px 3px;}
10. Use external scripts – Instead of placing tons of code in your header.php file, use external scripts. This allows the browser to cache the script so it won’t have to read it for every other page.
11. Validate your code at W3C to make sure you don’t have any major errors slowing down your page.
12. Allow progressive rendering: Load CSS files at the top of the page, from within the head section; load JavaScript files at the bottom of the HTML. And/Or…
13. Stop slow loading scripts from breaking your blog with IFrameWidgets v1.0 WordPress plugin. Slow widgets or snippets of Javascript can either time-out, or prevent the items below them from loading. The plugin creates WordPress sidebar widgets that run in an IFrame. Since IFrames load in parallel to the rest of the page, slow loading JavaScript widgets won’t affect the rest of the page.

Plugins

1. Disable or delete unused plugins – some plugins have tons of script and code, and even create database tables in your WordPress database. Use only the plugins you really need, and delete the rest.
2. Sometimes plugins require that you add a snippet of code to your theme’s template files to call the plugin. Usually, it looks something like this:
   < ?php refer_plugin(); ?>
   However, if for some reason you disable that plugin, you will get an error. Joost de Valk recommends using PHP’s special function called function_exists to prevent the blog from breaking if plugins are disabled or removed. Using it will make the code look like this:
   < ?php if (function_exists(‘refer_thanks’)) { refer_thanks(); } ?>
3. Control when your WordPress plugins are loaded: WordPress processes all of the code for all active plugins, even if that plugin isn’t used on a particular page. If a particular resource heavy plugin isn’t used on certain pages, then you can tell WordPress not to load it on those pages by wrapping an if statement around the content of each function to check what page is being loaded. Learn more about how to do this here and here.

Database

1. Use phpMyAdmin to optimize your database: Log in to phpMyAdmin, select all the tables, and then “repair” and “optimize.”
2. Delete excess records in your WordPress database. All plugins use the wp_options table to store data, which is the same table used by WordPress to store all settings for your blog, and is accessed every time you open any page. When you deactivate a plugin, these records are left behind, bloating your database. To clean it up you can use the WordPress Clean Options Plugin, which finds orphaned options left after you have removed plugins and removes them from the wp_options table, or manually as follows: Back up your database, login to phpMyAdmin, open your blog’s database, and click on browser for the wp_options table. Go through this table record by record to identify any records left behind by old plugins. (from WordPress Web 2.0 Spot-Er).
3. Use the Optimize DB plugin to optimize the tables of your database.
4. Use WordPress Plugin: Fix Database to check all tables in your database and fix any errors.
5. Lester “GaMerZ” Chan’s WP-DBManager 2.11 plugin sorts your database backup files by date in descending order, can repair databases, and allows automatic scheduling of database backups and optimization.

Caching and protecting for server overload

1. WordPress has a built-in caching system. Learn how to enable the default WordPress object cache. This has apparently been disabled in version 2.5.
   
2. WP-Cache 2 – caches Worpress pages and stores them in a static file for serving future requests directly from the file rather than loading and compiling the whole PHP code and then building the page from the database.
3. WP Super Cache – This plugin is a fork of the WP-Cache 2 plugin, and generates html files which are served without ever invoking a single line of PHP.
4. PHP Speedy – PHP Speedy is a script that you can install on your web server to automatically speed up the download time of your web pages.
5. Use the Expires and cache-control max age headers for all pages; Make dynamic pages support the if-modified-since request header; Use far future expiry headers on static resources; Use the cacheability engine to test that you have caching and validation set up correctly. If you don’t know what all this means, don’t worry, neither do I, but you can find out more here.
6. Digg Protector plugin – The Digg Protector will determine if a visitor is from Digg, and if the visitor is indeed from Digg, the plugin will serve them a remotely-hosted version of the image. Otherwise, the plugin will serve the locally-hosted (on that server) image.
7. Some more caching possibilities: MySQL query cache, PHP Compiler Cache. Learn more here.
8. Configure Apache for maximum performance.

Happy Optimization!

Sources:

Speed up your website: Part One

How-to: Optimize your site for speed – really excellent article with practical tips

How to Enable the Default WordPress Object Cache – talks about wp-cache, wp-cache 2, and built in wordpress caching.

Digg Protector

4 Simple Ways To Speed Up WordPress

Speed up and clean up your WordPress!

5 Tips to Help Your Slow or Sluggish Blog or Web Site (Wordpress Especially)

Deleting excess records in your WordPress database

WordPress on Speed: 17 Tweaks to Accelerate your WP

The 3 Easiest Ways to Speed Up WordPress

WordPress Theme Hacks

Diggproof & Speed up Your Wordpress Blog

WordPress Optimisation: Control When Plugins Are Loaded

I check PageRank with a very handy Firefox Add-on called SearchStatus. It adds a little toolbar at the bottom of the browser that indicates PageRank, Alexa, and Compete rankings.

I just checked all of my sites, and they all were awarded a PageRank of 4/10. Is that good? Is that bad? I don’t know, but at least now they have a rank of some kind and I have something to tell people when they ask. It’s like they didn’t exist until Google benevolently bestowed upon them their rank.

What is PageRank? Well, Wikipedia has the following to say about it:

PageRank is a link analysis algorithm that assigns a numerical weighting to each element of a hyperlinked set of documents, such as the World Wide Web, with the purpose of “measuring” its relative importance within the set.

We care about it because if Google gives a site a higher PageRank, it means they see it as more important and it will probably do better in search results.

Interesting, but here’s the really important stuff:

PageRank was developed at Stanford University by Larry Page (hence the name Page-Rank^[1]) and later Sergey Brin as part of a research project about a new kind of search engine.

It’s named after Larry Page! It worked out so well for him that his last name isn’t Wolfsonbergerstein. WolfsonbergersteinRank just wouldn’t have the same ring to it.

I started WordPress Garage in order to document my discoveries about WordPress. It was meant to serve as an online manual of sorts. So I decided to go back in time to see what I was blogging about close to the beginning of my WordPress journey.

I can see that the issues that interested me most at that time were related to optimizing blogs for search engines and readers. Here are the tips that most interested me at that time:

• Tags – Tags are useful for more detailed categorization of posts, search engine optimization, and user navigation. I wanted to find the perfect tagging plugin that not only would add tagging, but enable me to create tag clouds and list related posts based on those tags, so that I could use one plugin for three features. First I tried Jerome’s Keywords Plugin, only to find that it didn’t work once I upgraded from WordPress version 2.1.1 to 2.1.2. I then tried out Simple Tagging, which works wonderfully and does everything I want it to do, and now use it on all WordPress blogs and sites that I build.
• Excerpts – if you use <?php the_excerpt() ?> instead of <?php the_content() ?> in your template files so that certain pages automatically display excerpts instead of the full text of the post, all html tags are stripped from the text. That means that if you have images or links in the first paragraph or so of text, they are removed from the excerpt. Annoying. I searched for a solution and found The Excerpt Reloaded plugin. Only, it didn’t work quite right – if my excerpt had a bulleted list in it, for example, the entire page following that excerpt would be styled as one long list. But Rob, a blessed plugin developer, created a mod of the plugin that fixed this problem. I highly recommend using this plugin if you want to automatically display excerpts and retain the formatting.
  Excerpts and videos: even with Rob’s plugin, videos that are embedded in the beginning of any post will not appear in excerpts – only the code will. So far, the only way that I have found for displaying videos in excerpts is to stop using <?php the_excerpt() ?> and to manually insert excerpts.
• Future posting – this is a tip that I learned from Lorelle. When I first started blogging, I would write five posts on one day, and then publish nothing for the next couple of days. Not a very good strategy, since people, and maybe even search engines, like to see new content on a daily basis. So I started future posting whenever possible, which gave me some peace of mind for a few days where I knew I could take a break from blogging.

The above tips are pretty basic, but I think they can mean the difference between a well optimized and usable blog, and one that doesn’t reach its potential.

Therefore, it is worthwhile to try to clean up the database every once in a while. Optimize DB makes it easy for you to do that. Simply upload, activate, and go to Manage > Optimize DB.

Optimize DB»

Here’s the description:

This plugin tries to create a similar group of links for your blog. If you have enough links in your theme (Contextual Related Posts plugin comes in handy) for readers to explore, then as and when readers click on links, this plugin checks to see if it was referred from your blog, checks to see if it can identify a post or a page from the information it has and then adds a link to the referring page.

This has everything all rolled into one: it creates a sense of community and keeps visitors on your site. You can see it in action on the Weblog Tools Collection site. What a brilliant idea!

I am going to test this out as soon as I have some time.

Where did they go from here?»

Today I came across Dosh Dosh’s Comprehensive Guide to StumbleUpon. This guide helps to clarify some of the ways in which StumbleUpon works, but I am still mystified about a few things:

1. There is a page on StumbleUpon that allows you to search for reviews of your site. First of all, why is this page impossible to find? It should be easier to find than having to read an external guide to StumbleUpon to discover it exists. Second, I am getting traffic from StumbleUpon, yet when I searched for my URL on that page, nothing came up! Explain that one.
2. When I log in to StumbleUpon and do a search, I only get 10 results. Why? Where are the rest of the pages? Are these the top rated posts?
3. Some searches result in a page of tags. Is it because there are no results?

So StumbleUpon is still a mystery, but I feel like we’re getting closer to the answers…

A few days ago I wrote a post about protecting your WordPress site. It was, in my opinion, an average post. Well, someone out there must have thought it was something spectacular, because since then every few days the traffic to this blog spikes like crazy thanks to StumbleUpon! I’ve never seen anything like it before.

I still don’t get how StumbleUpon works. I mean, I know that you can “Stumble” pages on the web. But then what? Why is that particular post so popular? How are people finding it in StumbleUpon? Can I find out who Stumbled it and when? And why does the traffic spike every few days – what happens on those days that causes the spikes?

It’s all a mystery to me. But in the meantime I do understand one thing – StumbleUpon can be a serious source of traffic!

I have compiled a to-do list of plugins that I install and steps that I take to optimize and secure every WordPress site or blog that I create. This list will be updated with new developments or plugins and tips that I discover, so make sure to check back.

Must haves:

• Feedsmith – redirect all your feed subscribers to FeedBurner so that you can track your feed stats. Now FeedBurner allows you to keep your domain name in the feed address. This means that instead of your feed address becoming something like http://feeds.feedburner.com/WordpressGarage, it can be http://wpgarage.com/rss2 or whatever the feed address is for your site.
• Add FeedBurner feed flares to feed – make it easy for your RSS subscribers to bookmark or email your posts with Feed Flares
• Change permalink structure – use pretty permalinks for better search engine optimization. I always use the following custom permalink structure:
  /%category%/%postname%/
• Google (XML) Sitemaps - important for search engine optimization. This is not for your readers, but for the search engine crawlers that visit your site.
• Ultimate Google Analytics - this is an easy way to install Google Analytics on your site. There is another plugin that does this, but this one is “ultimate” because it also tracks outgoing links and links to downloads.
• Simple Tagging – tags are important for search engines and for Technorati. I tried all the other tagging plugins, and this is the easiest to use, and with it you can easily create a tag cloud and add related posts to each entry. Creating a tag cloud with Simple Tagging.
• Full Text Feed plugin – if you want your RSS subscribers to be able to see full text feeds, and you plan on using the More tag in your posts to create excerpts, you need this plugin.
• WordPress Database Backup - if you value your work, install this! It will send a backup file of your database to your email on a regular basis.
• WP-ContactForm: Akismet Edition – easy to use, functional contact form.
• Search Everything – if you have Pages on your site (i.e. not posts) with important information, they should show up in search results on your site. By default, WordPress excludes Pages from search results.
• Wordpress Dashboard Editor – this allows you to easily get rid of all the incoming WordPress feeds that appear on your dashboard. I don’t find that they add any value for me, and I know that they would just confuse my clients, so I use this to get rid of them.
• DoFollow – if someone comments on your site, why not give them the gift of a link back to their site? Since I set up every site so that first comments from a commenter must be approved, I’m not worried about spammers getting links back to them.
• WP-Cache 2.0 – since you never know when you’re going to write that amazing post that the whole world will digg, install this so that when that day arrives, your servers(hopefully) won’t crash.
• Subscribe to Comments 2.1 – blogs are communities. Allow your commenters to follow comment threads by subcribing to comments.
• Add comments feed to header for more subscribers – this is a way to increase your comment feed subscribers by adding the Comments Feed to the list of feeds that are displayed when a user clicks on the RSS link in the browser.
• Hacked Antisocial (hacked version of Sociable) – you need to give your users an easy way to bookmark your posts. This plugin does this, while not diminishing your “link juice” – or WP Plugin: Gregarious – this is an efficient and customizable plugin that adds a little green icon at the end of posts, with wording of your choice (like “Bookmark this”), and when clicked opens a drop-down menu with a list of social sites for bookmarking, plus the option to email the post.
  
• ST Visualize Advanced Features or Advanced TinyMCE Editor – the default WYSIWYG editor in WordPress is painfully simple. A little known secret is that there are more buttons available, but they are hidden. The ST Visualize Advanced Features plugin adds a button to the toolbar that, when clicked, opens up another row of formatting buttons. The Advanced TinyMCE Editor plugin turns the toolbar into a full-fledged WYSIWYG with 60 functions!
• WP-PageNavi – puts nice pagination at the bottom of every page. This just increases usability and tells the user how many pages there are on the site, and where they are in the scheme of things.
• Yes-www – make sure that all pages are either with the “www” or without, depending on your preference. The advantage of this plugin is that it also deals with index.php requests, and redirects them accordingly.
• All in One SEO pack – optimizes titles, makes sure Google doesn’t spider duplicate content – or the SEO_Wordpress plugin – both prevent duplicate content spidering and generally improve the site for search engines. Now I use All in One SEO Pack only- it does everything, including meta keywords and descriptions, title optimization (list the post name first, and then the name of your blog, for SEO – like this: How to protect your WordPress site >> wpgarage.com. In the default installation, these elements appear with the blog name first, and then the post name).
• Viper’s Video Quicktags – the best solution for easily adding videos to posts – adds simple buttons to the advanced WYSIWYG editor for easily inserting all types of media formats in your posts and pages.
• Setting up pinging – you can enter ping addresses under Options>Writing in the admin. Here is a list of ping addresses that you can copy and paste into that box. Alternately, you can use an online pinging service, like King Ping. If you enter your blog URI on the King Ping site, it will ping 53 sites every time you post. These sites have been manually reviewed for suitability and quality.
• Submit site to Google, Technorati, Yahoo, Dmoz
• Secure the site – follow this list of directions to add greater security to your WordPress blog or site.
• Enrich RSS feed by adding copyright notice, comments and related posts

Nice to haves:

• Comment Email Responder Plugin – easily email commenters and post a comment in response in one shot
• Simple Spam Filter – more spam protection. Works in conjunction with Akismet
• Admin Themer – make modifications to the admin in a separate CSS file so they are preserved even when you upgrade.
• Landing Sites – when people come to your site from a search engine, show them other possible posts they may be interested in based on their search query
• WP-Chunk – shortens long URLs in comments so they don’t mess the layout
• WP – ©Feed – add copyright notice, related posts and comments to feed to stop sploggers and extend the reach of your feed
• Digg This – adds Digg button when your posts are digged/dugg
• Custom Query String – allows you to set how many posts will appear on different pages like Home, Search, Category
• No self pings plugin – if you link to another post in your own blog, it appears as a trackback. I don’t like these trackbacks, and delete them. This plugin stops self-pings automatically.
• Slug Trimmer – if you use pretty permalinks, they are formed from the titles of your posts. Sometimes the titles are long, and then you end up with a really long URL. This plugin trims the URLs automatically.
• SRG Clean Archives - this allows you to create a useful archive page, where the posts are divided up into months and years.
• Separate pingbacks and trackbacks from comments – makes the comments section more organized. This is not a plugin, but a hack to the template files. The TrackbackList Plugin v1.3 does this too.
• Optimize DB – Your WordPress database can get clogged with junk. This plugin optimizes your database simply and efficiently.
• Author Highlight – this highlights comments by the author of a post, making them stand out visually from the other comments. It is possible to do this by coding the template files and CSS too.
• OneClick – no more unzipping and then FTPing themes and plugins. OneClick allows you to upload plugin or theme files from the Admin panel, or right-clicking in Firefox. All you have to do is browse for the zip file and click “upload” and the plugin does the rest.

Useful:

• Sticky Menu – Sticky Menu lets you define an unlimited number of menus, in which you list the exact number of menu items you want to appear. Menu items can link to any pages, posts, etc., in your site or any URLs exterior to your site. You can define a class name for each menu item.
• Fancy pull-quotes plugin - instead of creating a style for pull-quotes, you can use this plugin to make it easier.
• TinyMCE Comments - this makes it easy for commenters to format their comment. It seemed to slow down my site a lot.
• cforms – the easies, most flexible form builder I have ever seen. You can have multiple forms on one site, add as many fields as you want, divide your form into sections, validate, style it, have email autoresponders, track submissions, and more!

Tips:

• 52 of the Best Ways to Promote your Blog and your Business

The suggestion, that worked for them, is to increase your PHP memory. This is why:

PHP is what is used to run Wordpress. It’s usually allowed a certain amount of memory to run scripts and do its thing. If your blog is big enough, or if your scripts are complex enough, it may reach it’s memory limit and quit the script. That’s what was happening in my case.

How do you fix it?

Well just email the host and ask them to increase the PHP memory. You can run the phpinfo function and find out how much memory your site has. The server that was having the issue had 8Mb of PHP memory. I asked the host to increase it to 20Mb and then everything worked great.

I haven’t experienced such problems yet, but I’m going to keep this tip filed away in case I need it!

Fix Wordpress Plugin Issues With Memory>>