Improve loading times of screens with large number of custom field data

Background:
When we load screens such as the edit screen, Jira retrieves all values of custom fields even if certain values are not in use. In cases where there is a large number of values, it has impact on loading times of the screen. The following is a sample scenario:

1. Install vanilla Jira.
2. Create a project.
3. Add 2000 versions to this project.

With this scenario, we tried the following:

1. Include 1 version picker custom field on "Edit Screen".
   • Then attempt to edit an issue.
   • Observe time taken via HAR. Time taken is about 1.6 seconds version.har.
2. Include 4 version picker custom fields on "Edit Screen".
   • Then attempt to edit an issue.
   • Observe time taken via HAR. Time taken is about 7.2 seconds version3c.har.

We see that Jira retrieves all possible values for the field even if it is not used on the issue.

Perhaps a suggestion here would be to retrieve only values that are used.

In the latest versions of JIRA after 8.0, Atlassian has focused more on the performance improvements and outcomes are below:

• Limit rendering only 30 Agile boards per page though we select "Boards" -> "View all Boards"
• Limit rendering only 25 custom field per page though we select "All Custom fields" from the Administration custom fields section.
  Post that we can quickly search the needed board/field based on our interest.

Above are a few examples that helped in gaining performance.
One good article is: https://blog.developer.atlassian.com/upcoming-performance-improvements-for-boards-and-backlogs-in-jira/

We hope that this suggestion would get the necessary attention and gets worked upon.