readFromDocValues attribute from Kibana saved objects API

Hello,

I recently upgraded my ELK stack from 5.6 to 6.8.
I noticed there is now a Kibana REST API to perform CRUD operations on saved objects such as index pattern.

After using it to retrieve some index pattern I saw that there is sometimes, in the API response, a "readFromDocValues" attribute on some fields of the index pattern.

I browsed on the Kibana doc and there is no mention of "readFromDocValues". Depending on the data in my Elasticsearch node, i have sometimes this attribute in API reponse and sometimes not.

Can you provide some insights about this attribute ? Is it a Kibana metadata ? What is its purpose ?

Thanks.

Best regards.

Yes, it's Kibana metadata, and it's related to Elasticsearch doc values.

Basically, things like date fields are read from doc values instead of queried directly from _source, so we can format the value in the correct timezone.