Enabling Solr for WordPress

Detailed information on using Apache Solr with WordPress.

Contributors: Christopher Matthews.

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Apache Solr is a system for indexing and searching site content. All plans except for a Basic plan can use Pantheon Solr.

Currently, the version of Solr on Pantheon is Apache Solr v3.6.

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Enable Solr from the Site Dashboard

Before you can start using Solr on WordPress, you need to add the Index Server to your site:

From your Dashboard, go to Settings > Add Ons > Apache Solr Index Server: Add:

Enable Solr from The Site Dashboard

This will provision Apache Solr containers for every environment for your site. You are now ready to begin integrating with WordPress.

Solr Search for WordPress

Pantheon supports and maintains Solr Search for WordPress (Solr Power). This plugin replaces the default search mechanism within WordPress while preserving the familiar integration methods within themes and widgets.

This plugin requires PHP version 7.1 or higher. See Upgrade PHP versions for more information on switching PHP versions.

Install and Configure Plugin

  1. Set the connection mode to SFTP for the Dev or Multidev environment via the Pantheon Dashboard, or with Terminus:

    terminus connection:set <site>.<env> sftp
  2. Install and activate the Solr Search for WordPress (Solr Power) plugin on the Dev or Multidev environment using the WordPress Dashboard, or with Terminus:

    terminus wp <site>.<env> -- plugin install --activate solr-power

    Or for WP Site Networks:

    terminus wp <site>.<env> -- plugin install --activate --network solr-power
  3. From the WordPress Dashboard, navigate to Solr Power (previously under Settings). You should see your site's Solr Server details within the Info tab.

  4. Select Indexing Options from the navigation bar and configure desired indexing options for Solr. Click Save Changes after making modifications.


    You can exclude pages or posts from being indexed by providing the numeric ID of the item (comma separated) in the Excludes Posts or Pages field.

  5. Index all publicly queryable post types by navigating to the Actions tab and clicking Start Index next to Index Searchable Post Types, or via Terminus:

    terminus wp <site>.<env> -- solr index

    For WP Site Networks, you will need to index all your subsites individually:

    terminus wp <site>.<env> -- url=example.pantheonsite.io/subsite solr index
  6. Deploy the plugin to the site's Test and Live environments after validation and testing.

  1. In Appearance > Widgets, add the Solr Search Widget in your desired widget position.

    Solr Widget

  2. In Solr Power > Facet Options tab, check AJAX Facet Search Support and enter the Div ID in AJAX Div ID (displays search results) eg. primary.

    Solr Settings

    The Div ID is where the search results will appear. You can use an existing Div ID in the page template, or you can create your own blank element using a unique ID name.

  3. Check your desired Facets and save your settings, then test the search functionality before committing the changes.

Optimize Index

For details, see the Optimize command document.



Custom schema.xml files exist outside of version control, and must be uploaded to each environment separately.

Upon activation of the plugin on the Dev or Multidev environment, a default schema.xml document is automatically sent to the Solr server. The schema.xml file is submitted automatically when deploying the plugin to another environment on Pantheon.

You can set a custom schema.xml by uploading it to the /wp-content/uploads/solr-for-wordpress-on-pantheon/ directory using SFTP. Then, from the plugin's Actions tab, look for Repost schema.xml and click on Execute.

Known Issues/Limitations

This plugin is under active development on GitHub. Use the issue queue for status updates and support. Pull requests are also welcome!


New, deleted, and modified posts and pages are automatically added to the Solr index. However, if you modify the indexing options within Solr Power, you must manually re-index the site on the Actions tab.

Enable Solr for AJAX and WordPress Dashboard

Use the solr_allow_ajax and the solr_allow_admin filters to allow Solr to work with AJAX and within the WordPress Dashboard.

Safely Remove Solr

The following code changes are required before Solr can be safely uninstalled and disabled:

  1. Uninstall the Solr Search for WordPress plugin. Review the Uninstall Plugins section of Working in the WordPress Dashboard and Drupal Admin Interface for detailed instructions.

  2. Ensure the default search mechanism is functioning.

  3. Commit and deploy these changes to the Live environment.

  4. Go to Settings, click Add Ons, and then click Remove for Solr.