Get field usage stats
- GET /{index}/_field_usage_stats
Get field usage information for each shard and field of an index. Field usage statistics are automatically captured when queries are running on a cluster. A shard-level search request that accesses a given field, even if multiple times during that request, is counted as a single use.
The response body reports the per-shard usage count of the data structures that back the fields in the index. A given request will increment each count by a maximum value of 1, even if the request accesses the same field multiple times.