Elasticseach - force a field to index only, avoid store - elasticsearch

Question

How do I force a field to be indexed only and not store the data. This option is available in Solr and not sure if it's possible in Elasticseach.

Answer 1

From document
By default, field values are indexed to make them searchable, but they
are not stored. This means that the field can be queried, but the
original field value cannot be retrieved.
Usually this doesn’t matter. The field value is already part of the
_source field, which is stored by default. If you only want to retrieve the value of a single field or of a few fields, instead of
the whole _source, then this can be achieved with source filtering
If you don't want field to be stored in _source too. You can exclude the field from source in mapping
Mapping:
{
"mappings": {
"properties": {
"title":{
"type":"text"
},
"description":{
"type":
}
},
"_source": {
"excludes": [
"description"
]
}
}
}
Query:
GET logs/_search
{
"query": {
"match": {
"description": "b" --> field description is searchable(indexed)
}
}
}
Result:
"hits" : [
{
"_index" : "logs",
"_type" : "_doc",
"_id" : "-aC9V3EBkD38P4LIYrdY",
"_score" : 0.2876821,
"_source" : {
"title" : "a" --> field "description" is not returned
}
}
]
Note:
Removing fields from source will cause below issue
The update, update_by_query, and reindex APIs.
On the fly highlighting.
The ability to reindex from one Elasticsearch index to another, either to change mappings or analysis, or to upgrade an index to a new major version.
The ability to debug queries or aggregations by viewing the original document used at index time.
Potentially in the future, the ability to repair index corruption automatically.