Custom Field Optimizer - Fields and ZERO projects

[Suresh Venkat]

In the Custom Field Optimizer View, there are Custom fields with Global context and a column says used by ZERO projects. Not sure what does this mean?
1. Does it mean - there are No Active projects, which are using this field?
2. Does it mean - there could be Archived projects, which could be using this field, but since we have archived the project or issues within a project (which could have used it in the past, but archived now), hence it shows ZERO project.

[Filipi Lima]

Gonna reply here in case other get to this question! I've spent a bit of time understanding this as part of a customer issue and the statement to make things clearer is the following:

The Custom Field Optimizer is only analyzing custom field contexts that are not limited to one or more projects. Given that, when it says "Used by zero projects" what it means is that the existing Global context for that custom field is not being used by any project.

The most common follow-up question is "But I can see other project(s) using this field, how come it's used by 0 projects?"

The answer is that you must have at least one other context besides the global one for that custom field and the issues are using the project specific context.

If you click on *Change Context* when it shows zero projects Jira will simply delete the global context.

It it shows one or more project then Jira will edit the Global context by limiting it to project that have value for the custom field and were using the global context before.

Cheers!

[Suresh Venkat]

Looks like 

1. Used by zero projects means that Jira's index does not show that the field has any value for any project or issue.
2. It is the case that the optimizer is ignoring archived issues, a bug opened about this here: https://jira.atlassian.com/browse/JRASERVER-73207
3. In large enterprise sized environments, there may be massive amounts of data and fields. This has been known to cause performance problems in the application. So ensuring that fields are efficiently configured and properly becomes important. You can read about this here:

• • https://confluence.atlassian.com/enterprise/managing-custom-fields-in-jira-effectively-945523781.html

So the optimizer was created to help admins quickly identify fields that may potentially be inefficient and can be removed or better configured.

[Brett Connor]

Expanding on Suresh's answer, this can happen if the SQL it's using times out. In this case you won't see the error but it will show as 0 projects. Use with caution!

[Rami Baccar]

It means that there is no issues belonging to an active project using this custom field.
But be careful this custom Field can be included in some Screen schemes, so it can be populated in the future.
Also this field can be a scripted fields or a special plugin field that have not to be populated with any values.
It could be also issues in archived projects, which used this field.
To be save don't use the optimizer in the case of "0 Project" because the optimizer will delete  the context and It's very difficult to restore it. In this case just assign this custom field to a dummy project to preserve the context.