Solr 8 Schema Reversion and Performance Issues

We are moving this incident to resolved as the immediate impact has been addressed. Below is the final update summarizing the current status, resolution steps, and ongoing work:
Current Status
The release of the Drupal module search_api_pantheon v8.2.1 has resolved the critical issue impacting Solr schema reverting. Customers who have upgraded to this version and re-posted their Solr schema should no longer experience issues following server reboots.
Next Steps for Customers

Upgrade Module: Ensure your site is using the latest version of the search_api_pantheon module (v8.2.1). Release notes here.
Post Schema: Use the module admin interface or Drush to re-post your schema to the Solr server.

Dashboard path: /admin/config/search/search-api/server/pantheon_solr8/pantheon-admin/schema
Drush command: drush search-api-pantheon:postSchema
If you have any questions or need assistance, our Support team is available to help.
Ongoing Engineering Efforts
While immediate issues have been addressed, Pantheon engineers are working to ensure that schemas persist during major platform updates. No further Solr 8 updates are planned until this enhancement is complete.
We appreciate your patience and collaboration throughout this process. If any related concerns arise, please don’t hesitate to reach out to our support team.

We are pleased to announce the release of version 8.2.1 on Drupal.org, which addresses the critical issue affecting the Pantheon Search API Admin page. Apply this update to resolve the issue and restore optimal performance.

For reference:
https://www.drupal.org/project/search_api_pantheon/releases/8.2.1

During our testing of the module updates, we identified an additional edge case that could cause content reversion. As part of our ongoing efforts to resolve this, we are implementing an update to the Pantheon internal services to address this behavior.

If you have any questions or need assistance with this update, our support team is here to help. We appreciate your patience and understanding as we work to ensure the best possible experience.

We are actively monitoring the situation and working closely with our Engineering team to resolve a critical issue impacting the Pantheon Search API Admin page.

Issue Overview:
A fatal error has been identified in certain scenarios after applying configuration to the Solr server.

Error Message:
Uncaught PHP Exception TypeError: "Drupal\search_api_pantheon_admin\Form\PantheonSolrAdminForm::getViewSolrFile(): Argument #2 ($contents) must be of type string, array given, called in /code/web/modules/contrib/search_api_pantheon/modules/search_api_pantheon_admin/src/Form/PantheonSolrAdminForm.php on line 82" at /code/web/modules/contrib/search_api_pantheon/modules/search_api_pantheon_admin/src/Form/PantheonSolrAdminForm.php line 108

We are in the final stages of developing a patch to address this error and will release it as soon as it's ready.

Please rest assured that resolving this issue is our top priority. If you encounter any further challenges, our support team is here to help. Thank you for your patience and understanding as we finalize the solution.

We are continuing to monitor for any customer reports of success or issues with the new module version.

For reference:
https://www.drupal.org/project/search_api_pantheon/releases/8.2.0
https://docs.pantheon.io/release-notes/2024/11/solr-module-8-2-0

Our support team is here to help with any questions or guidance needed. Please don't hesitate to reach out for further assistance.

We have published search_api_pantheon v8.2.0 on Drupal.org, which includes a critical patch to resolve Solr performance issues and prevent reversion to previous versions. Customers experiencing these issues will need to apply this update and subsequently post schema to the Solr server from their website through the module admin UI or with Drush.

For reference:
https://www.drupal.org/project/search_api_pantheon/releases/8.2.0
https://docs.pantheon.io/release-notes/2024/11/solr-module-8-2-0

Our support team is here to help with any questions or guidance needed. Please don't hesitate to reach out for further assistance.
Thank you for your patience as we worked to deliver this essential improvement.

A pre-release branch of the search_api_pantheon module has been pushed to the 8.1.x-dev branch on drupal.org. With this update, a core reload is called following a schema post from the dashboard (i.e. "/admin/config/search/search-api/server/pantheon_solr8/pantheon-admin/schema") or with Drush ("drush search-api-pantheon:postSchema"). This branch does not yet trigger a reload when "drush search-api-solr:reload" is invoked.

To avoid Solr schema reverts, customers can install the new branch of the module on their site with:

composer require 'drupal/search_api_pantheon:8.1.x-dev@dev'

And then post their schema update in the admin dashboard or with Drush. With the core reload attached to posting the schema, sites should no longer see schema revert.

We are continuing to work towards a stable release of this fix that will include reloads through search-api-solr.

We're making steady progress on resolving this issue and will provide another update in about 6 hours, or sooner if we have additional information.

Thank you for your patience as we work through this.

We are continuing to work on a fix for this issue and making progress. We'll post another update in 6 hours, or sooner if significant progress is made.

We are continuing our efforts to fix this issue and will provide updates within the next 6 hours.

Our team is actively working toward a solution for this issue. We'll post another update in 6 hours, or sooner if significant progress is made.

We're making progress on a fix for this issue and will provide another update in 2 hours, or sooner if more details become available.

We are continuing to work on a fix for this issue. The next update will be in 2 hours or as soon as we have more details.

Between November 5 and November 8, 2024, a critical security update was applied to Solr 8 across our platform. During this process, a subset of customers experienced issues with their Solr schema reverting to a previous version. This schema reversion may lead to challenges such as limited indexing of new content and disrupted search functionalities.

We believe we've discovered the source of the issue affecting schema stability, and an update to the Drupal Search API Pantheon module will be available soon.

In the interim, if you encounter any Solr indexing or search-related issues, please reach out to our support team for prompt assistance.