# How to a emit a value for a runtime field of type geo\_point?

**URL:** <https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889>\
**Category:** Elasticsearch\
**Created:** [May 1, 2021, 7:28pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889 "2021-05-01T19:28:31Z")\
**Posts on this page:** 10\
**Page:** 1

<div class="post-metadata">

**Author:** ![rcowart](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/rcowart/32/88091_2.png) [@rcowart](https://discuss.elastic.co/u/rcowart)\
**Post date:** [May 1, 2021, 7:28pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/1 "2021-05-01T19:28:32Z")

</div>

I am trying to execute a query for a `geo_point` value with a runtime mapping, which [according to the docs](https://www.elastic.co/guide/en/elasticsearch/reference/master/runtime-mapping-fields.html#runtime-mapping-fields) should work, but it is failing. `keywords` and `long` values work fine. For example...

Where `src.city.name` is a `keyword`...

```json
"city": {
  "type": "object",
  "properties": {
    "name": {
      "type": "keyword"
    }
  }
},

```

the following **works**...

```json
{
  "runtime_mappings": {
    "city.name": {
      "type": "keyword",
      "script": {
        "source": "if (doc.containsKey('src.city.name') && !doc['src.city.name'].empty) {emit(doc['src.city.name'].value)}"
      }
    }
  },
  "fields": [
    "city.name"
  ],
  "size": 1,
  "query": {
    "match": {
      "server.ipaddr": "192.0.2.11"
    }
  }
}

```

Result...

```json
"fields": {
  "city.name": [
    "Macroom"
  ]
}

```

However, using the same method for a `geo_point` fails.

Where `src.loc.coord` is a `geo_point`...

```json
"loc": {
  "type": "object",
  "properties": {
    "coord": {
      "type": "geo_point"
    }
  }
},

```

the following query **fails**...

```json
{
  "runtime_mappings": {
    "loc.coord": {
      "type": "geo_point",
      "script": {
        "source": "if (doc.containsKey('src.loc.coord') && !doc['src.loc.coord'].empty) {emit(doc['src.loc.coord'].value)}"
      }
    }
  },
  "fields": [
    "loc.coord"
  ],
  "size": 1,
  "query": {
    "match": {
      "server.ipaddr": "192.0.2.11"
    }
  }
}

```

The error given is...

```json
{
  "error": {
    "root_cause": [
      {
        "type": "script_exception",
        "reason": "compile error",
        "script_stack": [
          "... src.loc.coord'].empty) {emit(doc['src.loc.coord ...",
          " ^---- HERE"
        ],
        "script": "if (doc.containsKey('src.loc.coord') && !doc['src.loc.coord'].empty) {emit(doc['src.loc.coord'].value)}",
        "lang": "painless",
        "position": {
          "offset": 88,
          "start": 63,
          "end": 113
        }
      }
    ],
    "type": "search_phase_execution_exception",
    "reason": "all shards failed",
    "phase": "query",
    "grouped": true,
    "failed_shards": [
      {
        "shard": 0,
        "index": "test_index-2021.w17",
        "node": "mDbh3hqhPRi8x0WMRhf-fB",
        "reason": {
          "type": "script_exception",
          "reason": "compile error",
          "script_stack": [
            "... src.loc.coord'].empty) {emit(doc['src.loc.coord ...",
            " ^---- HERE"
          ],
          "script": "if (doc.containsKey('src.loc.coord') && !doc['src.loc.coord'].empty) {emit(doc['src.loc.coord'].value)}",
          "lang": "painless",
          "position": {
            "offset": 88,
            "start": 63,
            "end": 113
          },
          "caused_by": {
            "type": "illegal_argument_exception",
            "reason": "Unknown call [emit] with [[org.elasticsearch.painless.node.EDot@356bd657]] arguments."
          }
        }
      }
    ]
  },
  "status": 400
}

```

How must this query be modified to work with `geo_point` fields?

---

<div class="post-metadata">

**Author:** ![nik9000](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nik9000/32/44947_2.png) [@nik9000](https://discuss.elastic.co/u/nik9000)\
**Post date:** [May 1, 2021, 7:46pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/2 "2021-05-01T19:46:15Z")

</div>

I believe emit for geo\_points takes two numbers as parameters.

---

<div class="post-metadata">

**Author:** ![rcowart](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/rcowart/32/88091_2.png) [@rcowart](https://discuss.elastic.co/u/rcowart)\
**Post date:** [May 1, 2021, 8:10pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/3 "2021-05-01T20:10:25Z")

</div>

There are five ways to express a `geo_point`:

- as an object, with `lat` and `lon` keys.
- as a string with the format: `"lat,lon"` .
- as a geohash.
- as an array with the format: [`lon` , `lat`]
- as a [Well-Known Text](https://docs.opengeospatial.org/is/12-063r5/12-063r5.html) POINT with the format: `"POINT(lon lat)"`

The field in question is using the string expression. For example:

```json
"loc": {
  "coord": "51.9017,-8.9492"
},

```

The [docs say](https://www.elastic.co/guide/en/elasticsearch/reference/current/geo-point.html#_using_geo_points_in_scripts) - "When accessing the value of a geo-point in a script, the value is returned as a `GeoPoint` object". So when `emit()` is passed the value `doc['src.loc.coord'].value`, it is being passed a `GeoPoint` object already.

However, If you are correct that "_emit for geo\_points takes two numbers as parameters_", is this documented anywhere? What is the correct order `lat, long` or `long, lat`?

---

<div class="post-metadata">

**Author:** ![nik9000](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nik9000/32/44947_2.png) [@nik9000](https://discuss.elastic.co/u/nik9000)\
**Post date:** [May 1, 2021, 8:38pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/4 "2021-05-01T20:38:04Z")

</div>

Sorry. I wasn't involved with the docs for this one. Looks like it is `lat, lon`. [https://github.com/elastic/elasticsearch/blob/50152589cab00fbb984f9f40d68173addee5970f/server/src/main/java/org/elasticsearch/script/GeoPointFieldScript.java#L59](https://github.com/elastic/elasticsearch/blob/50152589cab00fbb984f9f40d68173addee5970f/server/src/main/java/org/elasticsearch/script/GeoPointFieldScript.java#L59)

---

<div class="post-metadata">

**Author:** ![rcowart](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/rcowart/32/88091_2.png) [@rcowart](https://discuss.elastic.co/u/rcowart)\
**Post date:** [May 2, 2021, 12:50pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/5 "2021-05-02T12:50:26Z")

</div>

After reviewing the painless source (thanks for the link @nik9000 ) I put together the following reference for `emit()`.

# `emit()`

| **Type** | **Function** | **Multiple Calls** |
| --- | --- | --- |
| `boolean` | `emit(boolean v)` | NO |
| `date` | `emit(long v)` | NO |
| `double` | `emit(double v)` | YES |
| `geo_point` | `emit(double lat, double lon)` | NO |
| `ip` | `emit(String v)` | YES |
| `keyword` | `emit(String v)` | YES |
| `long` | `emit(long v)` | YES |

## Emitting `geo_point` values

For most runtime field types document fields of the same type can be used directly as parameters. For example:

```auto
emit(doc['host.name'].value)

```

However for geo\_point fields, emit doesn't accept a `geo_point` object, rather latitude and longitude must be passed as two separate parameters. For example:

```auto
def geopoint = doc['location.coordinates'].value;
def lat = geopoint.lat;
def lon = geopoint.lon;
emit(lat, lon)

```

## Calling `emit()` multiple times in a script

For some field types emit() may be called multiple times in a script. Doing so will result in an array of values up to the maximum number of values allowed. The table above indicates which values support multiple calls.

The following is an example of how this is enforced by the Painless language, is as follows - note the call to `checkMaxSize()`:

```auto
public final void emit(long v) {
    checkMaxSize(count);
    if (values.length < count + 1) {
        values = ArrayUtil.grow(values, count + 1);
    }
    values[count++] = v;
}

```

> NOTE! The maximum number of values that can be emitted is 100. This is constant and cannot be overridden (`public static final int MAX_VALUES = 100;`).

String values are not limited by the number of values, rather by the number of characters. This is enforced by the Painless language as follows - note the check for `chars > MAX_CHARS`:

```auto
public final void emit(String v) {
    checkMaxSize(results.size());
    chars += v.length();
    if (chars > MAX_CHARS) {
        throw new IllegalArgumentException(
            String.format(
                Locale.ROOT,
                "Runtime field [%s] is emitting [%s] characters while the maximum number of values allowed is [%s]",
                fieldName,
                chars,
                MAX_CHARS
            )
        );
    }
    results.add(v);
}

```

> NOTE! The maximum number of characters that can be emitted is 1048576. This is constant and cannot be overridden (`public static final long MAX_CHARS = 1024 * 1024;`).

---

<div class="post-metadata">

**Author:** ![nik9000](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nik9000/32/44947_2.png) [@nik9000](https://discuss.elastic.co/u/nik9000)\
**Post date:** [May 2, 2021, 2:39pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/6 "2021-05-02T14:39:53Z")

</div>

I believe they all support multiple calls. I could have sworn we had a table like this somewhere but I sure don't see it.

---

<div class="post-metadata">

**Author:** ![rcowart](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/rcowart/32/88091_2.png) [@rcowart](https://discuss.elastic.co/u/rcowart)\
**Post date:** [May 2, 2021, 3:47pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/7 "2021-05-02T15:47:08Z")

</div>

When I review the underlying Java code it didn't look like there was any special handling for those marked `NO`, i.e. nothing keeping track of the count or checking it compared to MAX\_VALUES. However, Java is not my thing, so I may have missed something.

---

<div class="post-metadata">

**Author:** ![rcowart](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/rcowart/32/88091_2.png) [@rcowart](https://discuss.elastic.co/u/rcowart)\
**Post date:** [May 2, 2021, 3:54pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/8 "2021-05-02T15:54:03Z")

</div>

The good news is that we are able to [reduce the storage requirement for our dataset by ~44%](https://twitter.com/robcowart_com/status/1388852776889995271) (measured by feeding in data --\> stopping ingestion --\> force merging --\> checking index stats API).

Up next is benchmarking ingest performance and query performance.

---

<div class="post-metadata">

**Author:** ![nik9000](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nik9000/32/44947_2.png) [@nik9000](https://discuss.elastic.co/u/nik9000)\
**Post date:** [May 3, 2021, 12:50pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/9 "2021-05-03T12:50:00Z")

</div>

Nice! I double checked the logic and they all allow emitting multiple values. `boolean` counts `true` and `false` values and doesn't actually store them at all so it never checks against the limit because multiple calls to emit don't cost any space. `long` checks the limit, like you saw. `date` and `geo_point` use `long`'s limit tracking code.

I asked around and we don't have a table like you described. I'm going to add something here: [https://www.elastic.co/guide/en/elasticsearch/painless/7.12/painless-runtime-fields-context.html](https://www.elastic.co/guide/en/elasticsearch/painless/7.12/painless-runtime-fields-context.html)

---

<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:** [May 31, 2021, 12:50pm UTC](https://discuss.elastic.co/t/how-to-a-emit-a-value-for-a-runtime-field-of-type-geo-point/271889/10 "2021-05-31T12:50:07Z")

</div>

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