# Fucntion Score with Random Score is ignoring a simple sort

**URL:** <https://discuss.elastic.co/t/fucntion-score-with-random-score-is-ignoring-a-simple-sort/179604>\
**Category:** Elasticsearch\
**Created:** [May 4, 2019, 4:07am UTC](https://discuss.elastic.co/t/fucntion-score-with-random-score-is-ignoring-a-simple-sort/179604 "2019-05-04T04:07:16Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![devpsic](https://avatars.discourse-cdn.com/v4/letter/d/ecb155/32.png) [@devpsic](https://discuss.elastic.co/u/devpsic)\
**Post date:** [May 4, 2019, 4:07am UTC](https://discuss.elastic.co/t/fucntion-score-with-random-score-is-ignoring-a-simple-sort/179604/1 "2019-05-04T04:07:17Z")

</div>

Hi,

I have a search within my index that currently works, I want to get the professionals that have a subscription first (is\_subscribed BOOLEAN) and then follow with the rest of users. I achieve this using the query:

```
POST /my_index/professionals/_search
{
  "from":0,
  "size":40,
  "query":{
     "constant_score":{
        "filter":{
           "bool":{
              "should":[
                 {
                    "term":{
                       "primary_locality_id":4
                    }
                 },
                 {
                    "term":{
                       "secondary_locality_id":4
                    }
                 }
              ]
           }
        }
     }
  },
  "sort":[
     {
        "is_subscribed":{
           "order":"desc"
        }
     }
  ]
}

```

This is giving the expected output, but to be fair to our users we would like to randomly seed this results while keeping the prioritised items (in this case, is\_subscribed: true) on the top and follow with the rest. Googling, I ran into the function\_score using a random\_score and a seed in order to randomise the items. I wrote this query:

```
{
   "from":0,
   "size":57,
   "query":{
      "function_score":{
         "query":{
            "constant_score":{
               "filter":{
                  "bool":{
                     "should":[
                        {
                           "term":{
                              "primary_locality_id":4
                           }
                        },
                        {
                           "term":{
                              "secondary_locality_id":4
                           }
                        }
                     ]
                  }
               }
            }
         },
         "random_score":{
            "seed":1484879348
         }
      }
   },
   "sort":[
      {
         "is_subscribed":{
            "order":"desc"
         }
      }
   ]
}

```

That will return always _the same results_, no matter what the seed is. I know this is happening because of my this part:

```
"sort":[
  {
     "is_subscribed": {
        "order":"desc"
     }
  }
]

```

This is affecting the `function_score`, as if I remove then the results are actually randomised and they respect the different `random_score.seed` value. But that doesn't fix my issue, as I still need to prioritise those subscribed users.

I've read through the documentation and Googled and couldn't find a way of combining both in a way the sort has better priority. What I am missing out? What's the way of first sorting and then randomising?

Thanks in advance,

---

<div class="post-metadata">

**Author:** ![polyfractal](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/polyfractal/32/48162_2.png) [@polyfractal](https://discuss.elastic.co/u/polyfractal)\
**Post date:** [May 6, 2019, 4:01pm UTC](https://discuss.elastic.co/t/fucntion-score-with-random-score-is-ignoring-a-simple-sort/179604/2 "2019-05-06T16:01:18Z")

</div>

Sort orders essentially throw away the score that is generated by the fulltext query, and sort only by the provided sort values by default.

If you want the value of `is_subscribed` to merged into the score there are two options:

- Add `"_score"`as a sort order and [enable score tracking](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-sort.html#_track_scores) which is turned off by default when sorting by a field. This will treat the `_score` as a tie-breaker in the sort ordering. For example, if you sort by `is_subscribed` first, `_score` will only be used to sort documents that share the same `is_subscribed`. So `is_subscribed: true` come first, then all the subscribed values get sorted by `_score`, then all the `is_subscribed: false` come next, sorted by score, etc

- Remove the sort parameter and add some kind of query which looks at `is_subscribed` and merges that into the overall score in some fashion (part of a boolean `must` clause, boosting, etc). This is the more flexible option, but also doesn't guarantee complete ordering of one field first like the sort param does. E.g. there might be a `is_subscribed: false` which ranks higher than `true` if it has a particularly rare token that scores highly or something.

---

<div class="post-metadata">

**Author:** ![devpsic](https://avatars.discourse-cdn.com/v4/letter/d/ecb155/32.png) [@devpsic](https://discuss.elastic.co/u/devpsic)\
**Post date:** [May 12, 2019, 2:19pm UTC](https://discuss.elastic.co/t/fucntion-score-with-random-score-is-ignoring-a-simple-sort/179604/3 "2019-05-12T14:19:20Z")

</div>

Hi @polyfractal

Thank you for your detailed answer and both options. From what I read, seems that only the first one is the option I should follow as the second might give some false positives.

I've gone ahead and re-wrote my query to include the score tracking and also sort by `"_score"` but seems that isn't really giving me the output you were saying.

This is my rewritten query:

```
{
   "track_scores": true,
   "from":0,
   "size":57,
   "query":{
      "function_score":{
         "query":{
            "constant_score":{
               "filter":{
                  "bool":{
                     "should":[
                        {
                           "term":{
                              "primary_locality_id":4
                           }
                        },
                        {
                           "term":{
                              "secondary_locality_id":4
                           }
                        }
                     ]
                  }
               }
            }
         },
         "random_score":{
            "seed": 1
         }
      }
   },
   "sort":[
      {
        "is_subscribed":{
            "order":"desc"
        },
        "_score" : {
             "order":"desc"
        }
      }
   ]
}

```

As you see, I enable the score tracking and sort by `is_subscribed` first and then by `_score`, but my results aren't showing the `is_subscribed: true` first:

Here is the detailed output with some redacted information:

```
{
  "hits": {
    "hits": [
      {
        "sort": [
          0.99855137,
          1
        ],
        "_type": "professionals",
        "_source": {
          "first_name": "First Name",
          "is_subscribed": true,
          "primary_locality_id": 4,
        },
        "_score": 0.99855137,
        "_index": "my_index",
        "_id": "2051766"
      },
      {
        "sort": [
          0.9551844,
          1
        ],
        "_type": "professionals",
        "_source": {
          "first_name": "First Name",
          "is_subscribed": true,
          "primary_locality_id": 4,
        },
        "_score": 0.9551844,
        "_index": "my_index",
        "_id": "2051648"
      },
      {
        "sort": [
          0.95447606,
          1
        ],
        "_type": "professionals",
        "_source": {
          "first_name": "First Name",
          "is_subscribed": true,
          "primary_locality_id": 4,
        },
        "_score": 0.95447606,
        "_index": "my_index",
        "_id": "2051322"
      },
      {
        "sort": [
          0.93707305,
          0
        ],
        "_type": "professionals",
        "_source": {
          "first_name": "First Name",
          "is_subscribed": false,
          "primary_locality_id": 4,
        },
        "_score": 0.93707305,
        "_index": "my_index",
        "_id": "2051063"
      },

        // 8 more results with is_subscribed: false

      {
        "sort": [
          0.8206227,
          1
        ],
        "_type": "professionals",
        "_source": {
          "first_name": "First Name",
          "is_subscribed": true,
          "primary_locality_id": 4,
        },
        "_score": 0.8206227,
        "_index": "my_index",
        "_id": "2050420"
      },
      
        // 4 more results with is_subscribed: false,

      {
        "sort": [
          0.7055144,
          1
        ],
        "_type": "professionals",
        "_source": {
          "first_name": "First Name",
          "is_subscribed": true,
          "primary_locality_id": 4,
        },
        "_score": 0.7055144,
        "_index": "my_index",
        "_id": "2050676"
      },
      {
        "sort": [
          0.6966923,
          1
        ],
        "_type": "professionals",
        "_source": {
          "first_name": "First Name",
          "is_subscribed": true,
          "primary_locality_id": 4,
        },
        "_score": 0.6966923,
        "_index": "my_index",
        "_id": "2051403"
      },
      {
        "sort": [
          0.6890349,
          0
        ],
        "_type": "professionals",
        "_source": {
          "first_name": "First Name",
          "is_subscribed": false,
          "primary_locality_id": 4,
        },
        "_score": 0.6890349,
        "_index": "my_index",
        "_id": "2050821"
      },
      
      // more mixed results

    ],
    "total": {
      "relation": "eq",
      "value": 57
    },
    "max_score": 0.99855137
  },
  "_shards": {
    "successful": 1,
    "failed": 2,
    "skipped": 0,
    "total": 3,
    "failures": [
      {
        "node": "xxxx",
        "index": ".kibana_1",
        "reason": {
          "index_uuid": "UQFK_z99SyeqezAmXfF_Nw",
          "index": ".kibana_1",
          "reason": "No mapping found for [is_subscribed] in order to sort on",
          "type": "query_shard_exception"
        },
        "shard": 0
      },
      {
        "node": "yyyy",
        "index": ".kibana_task_manager",
        "reason": {
          "index_uuid": "8U3zm8bKRROdd92wY_Scdw",
          "index": ".kibana_task_manager",
          "reason": "No mapping found for [is_subscribed] in order to sort on",
          "type": "query_shard_exception"
        },
        "shard": 0
      }
    ]
  },
  "took": 11,
  "timed_out": false
}

```

I've read your answer multiple times, but I can't figure out what I am doing wrong. I'm using the `_score` correctly to sort the results?

Thanks in advance,

---

<div class="post-metadata">

**Author:** ![devpsic](https://avatars.discourse-cdn.com/v4/letter/d/ecb155/32.png) [@devpsic](https://discuss.elastic.co/u/devpsic)\
**Post date:** [June 3, 2019, 9:22am UTC](https://discuss.elastic.co/t/fucntion-score-with-random-score-is-ignoring-a-simple-sort/179604/4 "2019-06-03T09:22:29Z")

</div>

Hi @polyfractal

I haven't been able to resolve the issue mentioned above, any idea idea why `_score` is not being sorted correctly?

Thanks in advance!

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 1, 2019, 9:22am UTC](https://discuss.elastic.co/t/fucntion-score-with-random-score-is-ignoring-a-simple-sort/179604/5 "2019-07-01T09:22:34Z")

</div>

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