Slow performance, slow and long running crons

This article describes how to solve site performance issues and slow running and stuck crons caused by flat tables and indexers having been enabled.

AFFECTED PRODUCTS AND VERSIONS

• Adobe Commerce on cloud infrastructure 2.1.x and above
• Adobe Commerce on-premises 2.1.x and above
• Magento Open Source 2.1.x and above

Issue

Flat indexers can cause:

• Heavy SQL load and site performance issues.
• Long running and stuck crons.

Cause

Flat tables and indexers enabled.

Solution

Starting with Adobe Commerce and Magento Open Source 2.1.x and above, the use of a flat catalog is no longer a best practice and is not recommended. Continued use of this feature is known to cause performance degradation and other indexing issues. To disable the flat catalog:

1. In the Admin, navigate to Stores > Settings > Configuration.
2. In the panel on the left under Catalog , choose Catalog.
3. Expand the Storefront section, and do the following:
   • Set Use Flat Catalog Category to No.
   • Set Use Flat Catalog Product to No.
4. When complete, click Save Config. Then when prompted, refresh the cache.
5. Flush cache by running php bin/magento cache:flush.

If you can’t change the Use Flat Catalog Category and Use Flat Catalog Product to No because the options are greyed out, disable flat indexers in app/etc/config.php:

1. Run this command to make sure all indexers are set to Update by schedule: php bin/magento indexer:set-mode schedule.
2. Edit app/etc/config.php and locate the lines with flat_catalog_product and flat_catalog_category - change them from 1 to 0 to disable them.
3. Run the command php bin/magento app:config:import
4. Run this command to confirm that the flat indexers are disabled: php bin/magento indexer:status.
5. Flush cache by running php bin/magento cache:flush.

Related Information

Reset stuck Adobe Commerce cron jobs manually on Cloud in our support knowledge base.