Elasticsearch Mapping - Rename existing field
You could do this by creating an Ingest pipeline, that contains a Rename Processor in combination with the Reindex API.
PUT _ingest/pipeline/my_rename_pipeline{ "description" : "describe pipeline", "processors" : [ { "rename": { "field": "fieldCamelcase", "target_field": "fieldCamelCase" } } ]}POST _reindex{ "source": { "index": "source" }, "dest": { "index": "dest", "pipeline": "my_rename_pipeline" }}
Note that you need to be running Elasticsearch 5.x in order to use ingest. If you're running < 5.x then you'll have to go with what @Val mentioned in his comment :)
Updating field name in ES (version>5, missing has been removed) using _update_by_query API:
Example:
POST http://localhost:9200/INDEX_NAME/_update_by_query{ "query": { "bool": { "must_not": { "exists": { "field": "NEW_FIELD_NAME" } } } }, "script" : { "inline": "ctx._source.NEW_FIELD_NAME = ctx._source.OLD_FIELD_NAME; ctx._source.remove(\"OLD_FIELD_NAME\");" }}
First of all, you must understand how elasticsearch and lucene store data, by immutable segments (you can read about easily on Internet).
So, any solution will remove/create documents and change mapping or create a new index so a new mapping as well.
The easiest way is to use the update by query
API: https://www.elastic.co/guide/en/elasticsearch/reference/2.4/docs-update-by-query.html
POST /XXXX/_update_by_query{ "query": { "missing": { "field": "fieldCamelCase" } }, "script" : { "inline": "ctx._source.fieldCamelCase = ctx._source.fieldCamelcase; ctx._source.remove(\"fieldCamelcase\");" }}