How custom mapping at elasticsearch?

I have a problem to showing string variable on grafana graph.
I have a error like this:

"Fielddata is disabled on text fields by default. Set fielddata=true on [....] in order to load fielddata in memory by uninverting the inverted index."

Can you help me for this?
I read many tutorials that say about " PUT my_index ...".
Im confused, how runs PUT command to enable fielddata.

Before you go and enable fielddata, I think there may be an better solution for you. By default, whenever you index a string field into Elasticsearch, it will create a .keyword multi-field. Those multi-fields are of type keyword, and do not require enabling fielddata. If you haven't already provided a mapping yet, those .keyword multi-fields should be available to you.

This multi-field can be accessed by simply adding .keyword to the field name. So, if you were trying to visualize a field called foo, try visualizing the field foo.keyword instead.

Oke thank you, I will try it..

Can I ask you about kibana or grafana?
Do you have experience about alerting on kibana or grafana?

I read many tutorial about alerting that say alerting of kibana need license? Is it true?
Because it, now I want explore alerting of grafana.

Yeah, Alerting in the Elastic Stack is a paid feature - it requires a Gold subscription.

I am not familiar with Grafana nor its alerting functionality.

Hmm..

For alerting feature, is it paid feature?
I need paid for elastic or kibana?

Kibana is part of the Elastic Stack. What you pay for is support for the Elastic Stack, including Kibana. This page has all the details: https://www.elastic.co/subscriptions