W3 Total Cache. The Most Complete WordPress Performance Framework

For now no; there are some special cases that we will address with an upcoming release for highly dynamic sites.

Right now we do not show the statistics in WP Admin, but soon we will provide graphs of: Page Cache Memory Use, Page Cache Hits/Misses, DB Cache Memory Use, DB Hits/Misses, Average Page Compression Savings, Average CSS Compression Savings, Average JS Compression Savings, Average Requests per Second, and Average Page Execution Time.

Well yes actually there are, simply enable debug mode on the “General” tab to have details appended to the bottom of your HTML source. Remember that when enabled all visitors to your blog can see these statistics if they view source. Using debug mode does slow the performance of your site so use sparingly.

You mean on the minify settings page right? Ok, it’s simple:
// tells the plugin to search for the file with the provided path from the document root, e.g.: ///JS/jquery/jquery.JS
/ tells the plugin to search for the file with the provided path from the server root, e.g. //JS/jquery/jquery.JS

In most cases providing an absolute path is sufficient and most reliable. You can of course use relative paths, but we discourage it unless you really know what you are doing.

Memory caching will not be possible. However you will be able to use both the page cache and minify in “disk” mode, as well CDN functionality without issue.

• Page Cache: Never cache the following pages, Cache exception list, Non-trailing slash pages
• Database Cache: Never cache the following pages
• CDN: Custom file list, Rejected files
  The CDN fields only support regular expression on the filename.

Examples (Never cache the following pages):

• Do not cache page/directory and sub pages
  /directory*
• Do not cache pages under a directory
  /directory/.+
• Do not cache pages that contain specific text
  /.*text.*
• Do not cache pages that is named child in directories
  .+/child
• Do not cache any pages named child
  */child

Note: To disable page caching of specific theme templates or plugin files you need to add define(‘DONOTCACHEPAGE’, true); to it.

Items expire from the cache at a rate that you specify. As far as how fast changes appear to your visitors, they appear instantly in most cases and if you’re an administrator who’s logged in they will always be immediately visible.

Even if your server was using an array of solid state disks (SSD), your server’s RAM is still going to be faster and introduce less overhead to access than even the fastest solid state drives on a PCIe bus. If you didn’t invest in solid state disks for your server, then even worse off – at least an order of magnitude speed difference in read operations in RAM versus HDD. For write operations delta the latency differences is even more pronounced. RAM is the winner hands down. We won’t even discuss the blocking and arbitration issues that happen with disk arrays under certain circumstances.

There’s no straight answer for this one. Since WordPress is a PHP-based application, we encourage everyone to install an opcode cache and realize a minimum of 10x performance gain. It will obviously make our plugin faster as well, so again please check out the installation instructions if you do not already use an opcode cache. Once installed, you can select an opcode cache as the method and get back to blogging.

Opcode caching does have a couple weaknesses:

• If you frequently restart your web server (e.g. apache) especially during high traffic periods, you will lose your cache and your site will slow down as it rebuilds the cache (which happens very quickly). However if you use memcached you would not lose your cache if your web server is restarted.
• More importantly, opcode caching is best suited for single server environments because the cache is only accessible to the local server, it cannot be shared with other servers in a multi-server (cluster) environment.

It would appear that using APC database caching may be best, but your mileage may vary. So depending on what software you install and how you manage your server, you can choose the options to fit your needs. If you need help with the install on your dedicated or virtual dedicated linux-based server ask us!

Let’s say you had a file of 10240 bytes, which becomes 2048 bytes when compressed, savings of ~80% (typical for CSS files). That same file will now have an additional ~3x-10x transfer speed improvement when minified. That’s a big return from a small operation. The larger your files, the more significant the proportional performance gains.

They never stop being dynamic, we just don’t create pages that have not been changed. If you have a page that updated frequently in your blog before, it will still remain up-to-date at all times.

We feel that caching objects after the first request and checking for updates before responding subsequent requests (which is kind of how web browsers work too) creates more opportunities for interesting applications and mashups where the blogosphere doesn’t require institutional investment to be able to handle developers making hundreds of requests every day the same way we use Google, Twitter and Facebook (for example) APIs today. Think about it, even when major search engines crawl your site, they have to be “gentle” so they don’t bring it down, let’s turn the paradigm around so that every blog can deliver content in real-time in various formats.

Add “/.+” (without the quotes) to page cache “Never cache the following pages” option on the page cache settings tab.

Enable “Cache feeds: site, categories, tags, comments” on the “Page Cache” settings tab. Some sitemap implementations are considered by WordPress to be “feeds.”

View your page source in your browser and search for any <style>, <link> or <script> tags that contain external CSS or JS files and one by one add them to the minify settings page. Do not include any CSS in conditional statements (unless you know what you are doing) like:

<!–[if lte IE 8]><link rel="stylesheet" type="text/css" href="/wp-content/themes/default/lte.css" media="screen,projection" /><![endif]–> Or simply use the “Help” tool available on the minify settings page which will identify CSS and JS files used in the templates of your theme and properly assign them to the same. Simply tick the checkbox for files you wish to minify, click “Apply & close”, then save your settings.

The plugin will combine, minify, HTTP compress and check for updates to these files automatically from now on. If you have any CSS or JS that are inline consider making them external files so that you can use them with minify.

Just place them above </head> if that’s where your embed is done or above </body> if that’s where you need them. Wherever they need to be to be called after the JS that needs them, it’ll be fine.

Yes you can, but since there are numerous ways to do so, so be sure to test your results carefully. Having said that we do encourage it as it will mean that less processing has to be done to deliver your pages.

First let me point out that in many cases we suggest putting all the JS that’s not required for interactivity with your site at the bottom of the document. Anything JS that makes the site work as intended we suggested embedding in the <head>. Depending on your specific situation, having the majority of your JS at the bottom of the document will mean that your visitors won’t have to download things they don’t want to begin interacting with your site or reading it’s content. Quite often the additional HTTP transaction is worthwhile.

Definitely. Removing white space from your files make gzip (HTTP compression) more effective.

Many developers like to have comments in the code for various reasons, however these comments add no value from the blog readers (or search engine for that matter) point of view and only contribute to increased load time and wasted bandwidth as a result. Now only you can use them and view them in your site (as a logged in administrator viewing the page source), which is really what (we assume) you intended.

<link> is a non-blocking method to embed CSS into a document. We recommend this approach for optimal performance.

In the case of objects (files) you don’t host yourself, this could add several seconds to your page’s load time as the DNS lookups, HTTP transaction roundtrip times and wait times add up. Even when all the scripts are hosted locally, the same adversities exist. Since all objects in the <head> of a document have to be ready before the page can be rendered, having them load in a parallel fashion as opposed to linear (or near linear) gives night and day results.

Nothing yet. We’re evaluating use cases to deal with common issues (like inline CSS for tag clouds for example).

Pretty much. If you monetize your blog with ads you will want to spend some time making sure that the ad code works well with your optimization settings. There are also the occasional pieces of code that conflict with the others and have to be in a specific order to work well, but that’s not a problem that this plugin introduces.

No, the plugin looks for conditional statements in your markup used for CSS (and sometimes JS) and makes sure that the minified files precede it, so keep that in mind.

Yes and no. In general, packed JS cannot be minified reliably. Obfuscated JS also is hit or miss. A minified and gzipped JS file will be smaller than a packed file in any case, so using the (uncompressed, unpacked or un obfuscated) developer versions of your plugins is no longer a concern when using this plugin. Alternatively, you can use the non-blocking embed option to continue to use your packed or obfuscated file without minification.

On the contrary, as with any other action a user can perform on a site, faster performance will encourage more of it. The cache is so quickly rebuilt in memory that it’s no trouble to show visitors the most current version of a post that’s experiencing Digg, Slashdot, Drudge Report, Yahoo Buzz or Twitter effect.

Unfortunately a 400 bad request error may be generated. So use the “Check URI” button to make sure that you have entered the correct URL or path to the file.

No. If you include a script in the minfy settings twice or it already exists in your theme we do not automatically remove the extra code. That’s tricky business and it’s better for us to just let you make the decisions conscientiously.

No, you can drag and drop them into the desired order on the minify settings page.

Steve Souders identified that placing inline scripts between JS and CSS embeds creates a blocking situation, so we’re try to help you avoid that. If you’d like to experiment with various scenarios related specifically to your blog, we recommend Steve’s tool, Cuzillion. Have some beneficial input on other common cases for WordPress users? Reach out to us.

Happy to! Login as an administrator, go to the Minify Settings page and check off “Show un-minified pages to administrators” and save the changes. Now stay logged in as an administrator in the same browser you used to change the settings and now when you view the source of a given page in the site, the source will not be minified.

On the minify settings tab, use the drop-down selection menu to define the CSS or JS files that appear on all pages using the “Default” group first. Then specify unie files for the other pages.

In case you were using @media declarations in your document, we’d have you covered. We will likely allow you to modify this attribute as subsequent features are finalized.

We have not found a use case where this appears to be of any consequence. If you’re aware of one please let us know.

No, this plugin is not similar. While valid HTML and W3C standards ensure consistent behavior across user agents and promote accessibility, any invalidity that exist in the code is not going to bring your site to its knees.

Unlikely, you’re saving them bandwidth and using their applications, so they will probably appreciate it as long as their application still works as intended and you’re using their software in an authorized manner. Look at it this way, even before this plugin, you and thousands of other people were still downloading it, now you’re just downloading it first.

You can! Just add Google’s script to your minify settings use non-blocking mode and your visitors will download jQuery directly from them as you wish. And the same is obviously true for any other library you wish. Remember you are creating additional DNS Lookups and HTTP transactions when you do this.

Currently you cannot, replacement is not yet supported.

This is definitely a special case. Files like “http://domain.com/wp-content/themes/default/js/script.js?ver=20090102″ etc need to be specified with the full URL. This is an exception to the general rule of specifying a local path to file like: “wp-content/themes/default/js/script.js”, which should also work fine. Be sure to click the “Verify URL” button to be sure that everything is ok before saving changes.

When using Minify and JS/CSS placement, custom placement, the following tags are available:

• <!– W3TC-include-css –>
  Used with “Auto” and “Manual”. Inserts the minified/combined CSS files at the location you choose.
• <!– W3TC-include-js-head –>
  Used with “Auto” and “Manual”. Inserts the minified/combined JS files. Embed location “in <head>” in “Manual” mode.
• <!– W3TC-include-js-body-start –>
  Used with “Manual”. Inserts the minified/combined JS files. Embed location “after <body>” in “Manual” mode.
• <!– W3TC-include-js-body-end –>
  Used with “Manual”. Inserts the minified/combined JS files. Embed location “before </body>” in “Manual” mode.

With the various hosted 3rd party applications available (from web site statistics to social media sharing widgets), the problems we’ve noticed are: additional HTTP transactions, DNS lookups and latencies from busy servers that we can’t control and often un-minified files with no HTTP compression all add up to a very slow page load and poor user experience. With your own copy of external files, updated as frequently as you wish, none of these problems exist.

Technically no, a CDN is a high performance cache that stores static assets (your theme files, media library etc) in various locations throughout the world in order to provide low latency access to them by readers in those regions.

First create an S3 account; it may take several hours for your account credentials to be functional. Next, you need to obtain your “Access key ID” and “Secret key” from the “Access Credentials” section of the “Security Credentials” page of “My Account.” Make sure the status is “active.” Next, make sure that “Amazon Simple Storage Service (Amazon S3)” is the selected “CDN type” on the “General Settings” tab, then save the changes. Now on the “Content Delivery Network Settings” tab enter your “Access key,” “Secret key” and enter a name (avoid special characters and spaces) for your bucket in the “Create a bucket” field by clicking the button of the same name. If using an existing bucket simply specify the bucket name in the “Bucket” field. Click the “Test S3 Upload” button and make sure that the test is successful, if not check your settings and try again. Save your settings.

Unless you wish to use CloudFront, you’re almost done, skip to the next paragraph if you’re using CloudFront. Go to the “General Settings” tab and click the “Enable” checkbox and save the settings to enable CDN functionality. Empty the cache for the changes to take effect. If preview mode is active you will need to “deploy” your changes for them to take effect.

To use CloudFront, perform all of the steps above, except select the “Amazon CloudFront” “CDN type” in the “Content Delivery Network” section of the “General Settings” tab. When creating a new bucket, the distribution ID will automatically be populated. Otherwise, proceed to the AWS Management Console and create a new distribution: select the S3 Bucket you created earlier as the “Origin,” enter a CNAME if you wish to add one or more to your DNS Zone. Make sure that “Distribution Status” is deployed and “State” is enabled. Now on “Content Delivery Network” tab of the plugin, copy the subdomain found in the AWS Management Console and enter the CNAME used for the distribution in the “CNAME” field.

You may optionally, specify up to 10 hostnames to use rather than the default hostname, doing so will improve the render performance of your site’s pages. Additional hostnames should also be specified in the settings for the distribution you’re using in the AWS Management Console.

Now go to the General tab and click the “Enable” checkbox and save the settings to enable CDN functionality and empty the cache for the changes to take effect. If preview mode is active you will need to “deploy” your changes for them to take effect.

We recommend that you use IAM to create a new policy for AWS services that have limited permissions. A helpful tool: AWS Policy Generator

You also find a S3 configuration sample in the “ini” folder in the plugins directory.

First create an account. Next, in the “Content Delivery Network” section of the “General Settings” tab, select Rackspace Cloud Files as the “CDN Type.” Now, in the “Configuration” section of the “Content Delivery Network” tab, enter the “Username” and “API key” associated with your account (found in the API Access section of the rackspace cloud control panel) in the respective fields. Next enter a name for the container to use (avoid special characters and spaces). If the operation is successful, the container’s ID will automatically appear in the “Replace site’s hostname with” field. You may optionally, specify the container name and container ID of an existing container if you wish. Click the “Test Cloud Files Upload” button and make sure that the test is successful, if not check your settings and try again. Save your settings. You’re now ready to export your media library, theme and any other files to the CDN.

You may optionally, specify up to 10 hostnames to use rather than the default hostname, doing so will improve the render performance of your site’s pages.

Now go to the General tab and click the “Enable” checkbox and save the settings to enable CDN functionality and empty the cache for the changes to take effect. If preview mode is active you will need to “deploy” your changes for them to take effect.

Login to your CDN providers control panel or account management area. Following any set up steps they provide, create a new “pull zone” or “bucket” for your site’s domain name. If there’s a set up wizard or any troubleshooting tips your provider offers, be sure to review them. In the “Content Delivery Network” tab of the plugin, enter the hostname your CDN provider provided in the “replace site’s hostname with” field. You should always do a quick check by opening a test file from the CDN hostname, e.g. http://cdn.domain.com/favicon.ico. Troubleshoot with yoru CDN provider until this test is successful.

Now go to the “General” tab and click the checkbox and save the settings to enable CDN functionality and empty the cache for the changes to take effect.

If the file exists in your document root (i.e. http://domain.com/favicon.ico), the plugin can take care of that for you using custom upload options. If the file is in your theme directory you can also have the plugin uploaded from there.

Yes, you can specify which file types you would like served by CDN and they will be uploaded and always downloaded from that location. This includes the smilies, JavaScript files et al. By default we take care of them all.

Yes! You can take advantage of the pipelining support in some browsers by creating a sub-domain for the static content for your site. So you could select the “Origin Push / Self-hosted” method of the General Settings tab. Create static.domain.com on your server (and update your DNS zone) and then specify the FTP details for it in the plugin configuration panel and you’re done. If you disable the scripting options on your server you’ll find that your server will actually respond slightly faster from that sub-domain because it’s just sending files and not processing them.

Yes, any CSS and JS you manage with the plugin are minified before being uploaded to your CDN. You don’t have to make any special changes to your theme. We encourage you to make sure that your provider supports HTTP compression as the benefit of having your static assets available from more than one POP alone is not enough.

That depends on how you use your blog and where most of your readers read your blog (regionally). Here’s a short list:

• MaxCDN
• EdgeCast
• Amazon Cloudfront
• Rackspace Cloud Files
• Limelight Networks
• Akamai

No, that is taken care of for you. Your CSS files will originate from your CDN provider and all paths to any images in your CSS will be changed from relative to absolute, making sure that they load just fine. Do nothing differently, yet reap all the benefits.

The media library import tool is for old or “messy” WordPress installations that have attachments (images etc in posts or pages) scattered about the web server or “hot linked” to 3rd party sites instead of properly using the media library.

The tool will scan your posts and pages for the cases above and copy them to your media library, update your posts to use the link addresses and produce a .htaccess file containing the list of of permanent redirects, so search engines can find the files in their new location.

You should backup your database before performing this operation.

If the domain name of your site has changed, this tool is useful in updating your posts and pages to use the current addresses. For example, if your site used to be www.domain.com, and you decided to change it to domain.com, the result would either be many “broken” images or many unnecessary redirects (which slow down the visitor’s browsing experience). You can use this tool to correct this and similar cases. Correcting the URLs of your images also allows the plugin to do a better job of determining which images are actually hosted with the CDN

As always, it never hurts to back up your database first.

To enable full page caching option you need to enable “edge mode”. If not already enabled this will
also enable Browser Cache and disable “Expires” header. This is because CloudFront does not cache properly
when “Expires” headers are set. When using CloudFront and full page caching there are no purging of cached pages when posting
new posts etc. Cache invalidations in CF is limited per month and also takes up to 15 minutes to complete.

Since there is no purging and you want to people to be able to comment it is recommended to use a hosted
commenting software, such as FaceBook Comments or Disqus. If you do not use this comments are not
shown after they been posted or approved.

Main step to get CloudFront full page caching working is to have your site on a different domain than the
one you want your visitors to see. So you should install or configure your site so its on a separate domain,
for example wp.example.com. You will then later configure example.com so its used by CloudFront.

How to configure CloudFront on AWS:

1. Go to AWS Console
2. Click “Create Distribution”
3. Select “Web”
4. Click “Continue”
5. Enter wp.example.com into “Origin Domain Name”
6. Enter CustomWWW-example.com into “Origin ID”
7. Set Origin Protocol Policy to HTTP Only (CloudFront will connect to my origin using only HTTP).
8. Select “Allow HTTP Methods” – GET, HEAD, PUT, PATCH, DELETE, OPTIONS
9. Select “Forward Query Strings” – Yes
10. Enter example.com (the domain that your visitors will type into their browser) into
    Alternate Domain Names(CNAMESs)
11. Set logging to “On”
12. Enter “webserverlog-example.com” into “Bucket for logs”
13. Enter “stats-logs/” into Log Prefix
14. Enter “CDN for example.com” into Comment.
15. Click “Create Distribution”

Configure DNS

1. Add new CNAME recored for example.com that points to the Domain Name that belongs to the distribution you created previously.

How to configure W3 Total Cache:

There are two methods to configure W3 Total Cache CDN. Origin Pull “CloudFront” or “Generic mirror”. If you want to be able to invalidate URLs from within WordPress you need to use the CloudFront option.
If you do not configure an CDN the wrong URLs will be used when linking to CSS, JS and other files.

Configure CloudFront:

1. Select Origin Pull (Mirror) Amazon CloudPront on General Page
2. Go to the CDN page.
3. Enter your AWS credentials
4. Enter example.com as an CNAME
5. Save Settings

Configure Generic Mirror:

1. Enter example.com into “Replace site’s hostname with:”
2. Save Settings

Entity tags were created to add more reliability to client side caching my providing a simple method for a browser to verify that a file had not changed since last it was downloaded. Using them helps enables your server return 304 or “not modified” responses instead of a 200 “ok” response which are much much slower (because the file is sent). The result is a visitor viewing multiple pages of your site would have that “instant loading” experience that we all definitely enjoy. Don’t worry we don’t use inodes to create our Etags so this solution is reliable for multi server hosting solutions.

Yes, we have Etags covered. Even if you have a clustered hosting environment, your Etags will be consistent (across multiple servers in your cluster) so you don’t have to worry about using special session cookies when you introduce our plugin. If you would like to specify headers for various reasons, you can do that as well.

We recommend UTF-8, but we do not modify the encoding in any files, instead we simply return the code as it is provided.

Indeed it does.

Yes.

To use all features in the suite, a minimum version of 2.8 is required. Earlier versions will benefit from our Media Library Importer to get them back on the upgrade path and into a CDN of their choosing.

No, on the contrary if you use the minify settings you will improve their performance by several times.

No. Any disk based page caching plugin you’re currently using would need to be completely uninstalled (not just disabled) in order to use this plugin. So if you have a development environment where you can try this out or testing during low traffic periods to get your preferences set, that is recommended. You can always backup your full WordPress installation before testing pretty quickly if you skip the /uploads/ (media library) directory.

Yes. Follow these steps:

1. Enable dynamic loading of ratings by checking GD Star Rating -> Settings -> Features “Cache support option”
2. If Database cache enabled in W3 Total Cache add “wp_gdsr” to “Ignored query stems” field in the Database Cache settings tab, otherwise ratings will not updated after voting
3. Empty all caches

You need to enable “User Agent Groups” high and low and add any user agents you think are missing.

Captcha and recaptcha will work fine, however you will need to prevent any pages with forms from being cached. Add the page’s URI to the “Never cache the following pages” box on the Page Cache Settings tab.

It is compatible with varnish.

It’s likely the plugin author modified their JS or CSS in the new release and any old CSS or JS you optimized with our plugin has introduced duplicate code as a result (creating a conflict). Simply check out the source code, identify any new CSS or JS and update your CSS and JS optimizations our plugin and you’re good to go.

If a theme or it’s files use the call php_flush() or function flush() that will interfere with the plugins normal operation; making the plugin send cached files before essential operations have finished. The flush() call is no longer necessary and should be removed.

First, make sure the plugin is not active (disabled) network-wide. Then make sure it’s deactivated network-wide. Now you should be able to successful upgrade without breaking your site.

Rule 2 says to use a content delivery network (CDN). The score for this rule is computed by checking the hostname of each component against the list of known CDNs. Unfortunately, the list of “known CDNs” are the ones used by Yahoo!. Most likely these are not relevant to your web site, except for potentially yui.yahooapis.com. If you want an accurate score for your web site, you can add your CDN hostnames to YSlow using Firefox’s preferences. Here are the steps to follow:

• Go to about:config in Firefox. You’ll see the current list of preferences.
• Right-click in the window and choose New and String to create a new string preference.
• Enter extensions.yslow.cdnHostnames for the preference name.
• For the string value, enter the hostname of your CDN, for example, mycdn.com. Do not use quotes. If you have multiple CDN hostnames, separate them with commas.

If you specify CDN hostnames in your preferences, they’ll be shown under the details for Rule 2 in the Performance view.

If this happens you need to add the following user agents to the textarea “Rejected user agents” the Page Cache settings page:

facebookexternalhit
FacebookExternalHit/1.1
FacebookExternalHit/1.0

Also make sure you have the correct xmlns:og /xmlns:fb tags in your opening HTML tag.

Great question. W3 Total Cache uses several open source tools to attempt to combine and optimize CSS, JavaScript and HTML etc. Unfortunately some trial and error is required on the part of developers is required to make sure that their code can be successfully minified with the various libraries W3 Total Cache supports. Even still, if developers do test their code thoroughly, they cannot be sure that interoperability with other code your site may have. This fault does not lie with any single party here, because there are thousands of plugins and theme combinations that a given site can have, there are millions of possible combinations of CSS, JavaScript etc.

A good rule of thumb is to try auto mode, work with a developer to identify the code that is not compatible and start with combine only mode (the safest optimization) and increase the optimization to the point just before functionality (JavaScript) or user interface / layout (CSS) breaks in your site.

We’re always working to make this more simple and straight forward in future releases, but this is not an undertaking we can realize on our own. When you find a plugin, theme or file that is not compatible with minification reach out to the developer and ask them either to provide a minified version with their distribution or otherwise make sure their code is minification-friendly.

If you put the symlink path in w3tc-wp-loader.php the plugin will think the path has changed because WordPress converts symlinks to realpath.
You can disable the check by adding: define(‘DONOTVERIFY_WP_LOADER’, true); to wp-config.php.

The plugin uses WordPress FileSystem functionality to write to files. It verifies that file owner, file owner group of created files match process owner. If this is not the case it cannot write or modify files.

Typically, you should ask your web host about the permissions issue and they should be able to resolve it.
You can however try adding define(‘FS_METHOD’, ‘direct’); to wp-config.php to circumvent the file and folder checks.

This is happens when CURL cannot find the proper location of certificates or the certificates have incorrect permissions. Ask your web host for help addressing this issue.

You need to enable Fragment Caching and use a theme based on Genesis.

You need to go the Genesis Extension settings page.
There you will a textbox called “Excluded single pages / posts:” there you need to enter the pages
that should not be cached by the fragment caching. The exclude textareas support regular expressions
so if the pages that are to be excluded are similar you can most likely enter one
expression that covers all your pages. For information on regular expression you need to search.

If you have anything dynamic in your widgets area, the sidebar, then you’ll need to disable the sidebar caching, or enter pages that should not have their sidedar cached.