Rollup search + aggregation total count

[rubarax (Ruben de Alba)]

Hi all,

I have a rollup job defined that groups by the following fields: server, user, method (it also handles different metrics not relevant for this question)

I know that I cannot use some aggregations types in the rollup searches (like cardinality), but... since I can aggregate by user:

GET rollup_index/_rollup_search
{
  "size":0,
  "aggs": {
    "daily": {
      "date_histogram": {
        "field": "timestamp",
        "interval": "24h"
      },
      "aggs": {
        "users": {
          "terms": {
                "field": "user",
                "size": 5000                
          }
        }
      }
    }
  }
}

and I only need the count of users, it doesn't make any sense that I have to retrieve the list of all users to get the total count.

So, is there any way so I can just get the total count?

Thanks in advance.