Optimizing WP-Cron performance using cron or Task Scheduler

Introduction to WP-Cron

WP-Cron is an important WordPress component responsible for processing scheduled tasks in WordPress core and plugins. The name originates from the cron time-based task scheduler available on UNIX systems.

What makes WP-Cron special is the fact that it works well on a broad range of environments including those with limited resources or limited access. Unlike regular cron implementations, it checks the list of scheduled tasks on every page load and immediately runs any tasks that are due.

While WP-Cron improves compatibility with different environments enormously, it does come with some major drawbacks:

• When there is little or no traffic on your site, tasks that are due do not run.
• Tasks that take longer than the maximum execution time (usually 30 or 60 seconds) fail in the middle of their execution.

The first drawback is specifically a problem for static sites where the dynamic WordPress installation is separate from the public-facing static site, and as such doesn’t receive much or any traffic. It also affects scheduled publications in Staatic Premium, which rely on WP-Cron to start.

Optimizing WP-Cron

Luckily, you can work around these limitations by integrating WP-Cron with the regular cron task scheduler or Windows Task Scheduler.

The easiest and also traditional way to achieve this is by setting up a task in the system’s task scheduler to call the wp-cron.php file using a web request. However, this does not solve the maximum execution time issue mentioned earlier, and adds challenges when your dynamic WordPress site is protected with HTTP basic authentication, which is recommended when hosting static WordPress sites with Staatic.

Therefore, we recommend WP-CLI, a command-line interface for WordPress whose wp cron command runs scheduled tasks that are due.

WP-CLI is included by many hosting providers as a standard feature, especially those that are specialized in WordPress hosting. Alternatively, WP-CLI can be installed manually by following these instructions.

macOS and Linux

Both macOS and Linux use cron as their time-based scheduling system. When you have command-line access to the server this is usually configured using the crontab -e command. Most hosts also provide a hosting control panel that allows you to set up cron tasks using a web-based interface. Consult your hosting provider’s documentation for detailed steps to configure cron tasks.

Cron tasks require a specific syntax:

<schedule> <task>

Where <schedule> consists of the following time and date fields and <task> is the command to execute.

Step values are also permitted after an asterisk, so if specifying a task to be run every five minutes, you can use */5 for the Minute field.

Note: unless explicitly configured, tasks run by cron are executed in the context of the user who set up the task.

The simplest way to run the tasks that are due is with the following command:

wp cron event run --due-now --path="/path/to/site"

As a cron task running every minute, this would result in:

*/1 * * * * wp cron event run --due-now --path="/path/to/site"

Windows

Windows provides the Windows Task Scheduler to schedule time-based tasks. The steps to configure tasks depend on your specific Windows version as well as your WordPress web server configuration.

The following assumes that you are running Windows 11 with the XAMPP server.

1. Open Task Scheduler by opening the Start menu and typing “Task Scheduler”, and then click Task Scheduler.

   

2. Open the Create Task Wizard by opening the Action menu and clicking Create Task.

   

3. Give the task a Name, for example “WP-Cron”.

4. Add a trigger by clicking the Trigger tab and clicking New…. In Advanced Settings check Repeat task every and type 1 minute. Select Indefinitely in the for a duration of option. Then click OK to save the trigger.

   

5. Add an action by clicking the Actions tab and clicking New…. Then Browse for the WP-CLI binary (e.g. C:\xampp\apps\wordpress\bin\wp.bat) and in Add arguments type cron event run --due-now. Then click OK to save the action.

   

6. Finally, click OK to create the task.

Disable WP-Cron on page load

Once the task has been scheduled using your system’s task scheduler, WordPress needs to be instructed to no longer run WP-Cron on each page load. It is no longer needed and only adds load to your server.

In order to disable WP-Cron on page load, add the following line to the wp-config.php file:

define('DISABLE_WP_CRON', true);

Ensure everything is working

WordPress includes a task that, by default, runs every hour. Conveniently, if a task is more than an hour late, this will be reported as a failure on the Site Health Screen. If there are no failures reported an hour after setting up WP-CLI cron, you can be sure that everything is working properly.