Exists filtering on non-searchable types

[ThomThomson]

Overview

the issue #52426 for adding the pre-aggregated histogram type to Kibana states that the histogram data type should be filterable using only the operators 'exists' and 'does not exist'.

The problem with this is that all fields that appear in the filter dropdown must be of a type that is searchable based on the field capabilities api. An approach to get around this would involve changing the isFilterable method (which determines which fields show up in the dropdown) to include any types marked as filterable. This change may result in undesirable behavior unless all the edge cases are understood. This issue is a place to discuss this change.

[ThomThomson]

@polyfractal, do you know of any cases where a non-searchable field would not work with an exists filter?

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[elasticmachine]

Pinging @elastic/kibana-app-arch (Team:AppArch)

[polyfractal]

So... it's not guaranteed, but in most cases a field will support exists queries even if they are not "searchable" (because they use the doc values to check).

There are some exceptions, e.g. the Rank Feature field does not support exists, but I did a quick skim and most other fields do, even those that are traditional not searchable (binary fields, histogram, _seq_no, etc)

I'm not sure how helpful that is since it's not universal, but it's probably safe to assume most types support exists for the general case.

[ppisljar]

Thank you for contributing to this issue, however, we are closing this issue due to inactivity as part of a backlog grooming effort. If you believe this feature/bug should still be considered, please reopen with a comment.