How to form index stats API? - elasticsearch

Question

ES Version : 7.10.2
I have a requirement to show index statistics, I have come across the index stats API which does fulfill my requirement.
But the issue is I don't necessarily need all the fields for a particular metric.
Ex: curl -XGET "http://localhost:9200/order/_stats/docs"
It shows response as below (omitted for brevity)
"docs" : {
"count" : 7,
"deleted" : 0
}
But I only want "count" not "deleted" field, from this.
So, in Index Stats API documentation, i came across a query param as :
fields:
(Optional, string) Comma-separated list or wildcard expressions of fields to include in the statistics.
Used as the default list unless a specific field list is provided in the completion_fields or fielddata_fields parameters
As per above when I perform curl -XGET "http://localhost:9200/order/_stats/docs?fields=count"
It throws an exception
{
"error" : {
"root_cause" : [
{
"type" : "illegal_argument_exception",
"reason" : "request [/order/_stats/docs] contains unrecognized parameter: [fields]"
}
],
"type" : "illegal_argument_exception",
"reason" : "request [/order/_stats/docs] contains unrecognized parameter: [fields]"
},
"status" : 400
}
Am I understanding the usage of fields correctly ?
If yes/no, how can I achieve the above requirement ?
Any help is much appreciated :)

Answer 1

You can use the filter_path argument, like:
curl -XGET "http://localhost:9200/order/_stats?filter_path=_all.primaries.docs.count
This will return you only one field like:
{
"_all" : {
"primaries" : {
"docs" : {
"count" : 10
}
}
}
}