# Looking for max like bucket aggregation

**URL:** <https://discuss.elastic.co/t/looking-for-max-like-bucket-aggregation/167806>\
**Category:** Elasticsearch\
**Created:** [February 11, 2019, 8:37am UTC](https://discuss.elastic.co/t/looking-for-max-like-bucket-aggregation/167806 "2019-02-11T08:37:53Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![krambambuli](https://avatars.discourse-cdn.com/v4/letter/k/d78d45/32.png) [@krambambuli](https://discuss.elastic.co/u/krambambuli)\
**Post date:** [February 11, 2019, 8:37am UTC](https://discuss.elastic.co/t/looking-for-max-like-bucket-aggregation/167806/1 "2019-02-11T08:37:53Z")

</div>

Hi everyone,  
I'm quite new to Elastic and not too familiar yet with query DSL in Elastic yet. I have an Elastic database with documents containing vehicle's position at various times. Due to bad reception some documents don't contain a `location` field.

Here's the mapping:

```
PUT /agg_test
{
    "settings" : {
        "number_of_shards" : 1,
        "number_of_replicas" : 1
    },
    "mappings": {
        "_doc": {
            "properties": {
                "location": {
                    "type": "geo_point"
                },
                "time": {
                  "type": "date"
                },
                "vehicle": {
                  "type": "keyword"
                }
            }
        }
    }
}

```

and the data

```
POST /agg_test/_doc/_bulk?refresh
{"index":{"_id":1}}
{"location": "52.374081,4.912350", "time": "2018-01-01T13:00:00Z", "vehicle": "vcl_1"}
{"index":{"_id":2}}
{"name": "Museum Het Rembrandthuis","time": "2018-01-01T14:00:00Z", "vehicle": "vcl_1"}
{"index":{"_id":3}}
{"location": "52.371667,4.914722", "time": "2018-01-01T13:00:00Z", "vehicle": "vcl_2"}
{"index":{"_id":4}}
{"location": "51.222900,4.405200", "time": "2018-01-01T14:00:00Z", "vehicle": "vcl_2"}
{"index":{"_id":5}}
{"location": "48.861111,2.336389", "time": "2018-01-01T13:00:00Z", "vehicle": "vcl_3"}
{"index":{"_id":6}}
{"time": "2018-01-01T14:00:00Z", "vehicle": "vcl_3"}

```

I'm interested in finding the last known position of each vehicle (together with the time it was recorded) to use for visualisation. So I thought I could filter for the ones with location, then group by vehicle, get the maximum timestamp (or better the record with the maximal timestamp) and then ...

What I currently have is

```
GET /agg_test/_search
{
  "query": {
    "exists": { "field": "location"}
  },
  "aggs": {
    "last_position": {
      "terms": {
        "field": "vehicle"
      },
      "aggs": {
        "max_time": {
          "max": {
            "field": "time"
          }
        }
      }
    }
  },
  "size": 0
}

```

As you see there is no way forward, as there is nothing like a bucket aggregation constructing a bucket where some field is maximized. Alternatively I'd need a way to use the output from the query (vehicle together with timestamp) to use as input for another query to get the locations but of course I don't want to do this manually but would like one query to do all of that. Another thing I was looking for was a pipeline aggregation I could use for my task.

As far as I know, none of the things I described above can be written as query in Elastic.

What is the best practice for queries like the one I want to make in Elastic? Thank you!

---

<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:** [February 15, 2019, 7:35pm UTC](https://discuss.elastic.co/t/looking-for-max-like-bucket-aggregation/167806/2 "2019-02-15T19:35:47Z")

</div>

I'm not quite sure I understand, are you wanting the `name` field of the most recent position for each vehicle?

The easiest way to get this information is a `top_hits` aggregation: [https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-metrics-top-hits-aggregation.html](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-metrics-top-hits-aggregation.html)

E.g. `terms` agg on `vehicle`, then `top_hits` ordered by date descending, size of 1. That should give you the most recent document for each `vehicle`

---

<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:** [March 15, 2019, 7:35pm UTC](https://discuss.elastic.co/t/looking-for-max-like-bucket-aggregation/167806/3 "2019-03-15T19:35:53Z")

</div>

Closed on March 15, 2019, 7:35pm UTC

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