Why is HyperUnique query towards a imutable segment will return different result?

[林学维]

Hi. Guys

I've use the follow json to query druid. but druid returns different result within different execution. I saw from another thread that setting the groupByIsSingleThreaded will enforce the result to be consistency. but i still get different result.

can someone help with more insight? 

@Fangjin Yang

{

  "aggregations": [

    {

      "type": "hyperUnique",

      "name": "ipv_uv",

      "fieldName": "user_name"

    }

  ],

  "dataSource": "datasource1",

  "descending": "false",

  "granularity": {

    "period": "P1D",

    "timeZone": "+08:00",

    "type": "period"

  },

  "intervals": [

    "2018-03-26T04:00:00+08:00/2018-03-26T05:00:00+08:00"

  ],

  "dimensions": [],

  "queryType": "groupBy",

  "context": {

  "useCache": false,

  "groupByIsSingleThreaded": true,

  "populateCache": false

  }

}