Optimize your custom fields
Custom fields can have a huge impact on the performance of your Jira instance. You can decrease this impact and speed up your Jira by improving the configuration of your custom fields. With custom field optimization in Jira, you can do it automatically.
For all of the following procedures, you must be logged in as a user with Jira administrator permissions. For details, see Permissions overview.
Identify custom fields that need optimization
Scan your custom fields to find and highlight those whose configuration can be optimized. The scan will exclude any custom fields created automatically by Jira Software and Jira Service Management.
- In the upper-right corner of your Jira application, select Jira administration, and then select System.
In the sidebar, navigate to Instance optimizer and select Custom fields optimization.
Select Scan. Depending on the size of your instance, it might take some time. Just leave it running and come back later.
View scan results
When the scan is complete, it'll show you why custom fields were highlighted and how many of them can be optimized. 
Scan: Action to start the scan, or to run it again.
Recommendation: Shows why custom fields are highlighted, and tells you how many fields can be optimized.
Manage global fields: Takes you to the page with highlighted custom fields, where you can optimize them.
Custom fields with global contexts
These custom fields are available to all projects in your Jira instance. For more info on how to optimize these fields, see Custom fields with global contexts.
Custom fields and archived issues
Archived issues are deleted from the Jira index. Due to this, the custom fields optimization feature doesn’t have complete information about the issues that use a particular custom field.
This can result in some unwanted behavior, such as custom fields not displaying for archived issues and for the issues that have been restored. For more information, refer to our knowledge base article Custom field optimizer and archived issues.