# Storing a floating-point value in a long field: what, no mapping error?

**URL:** <https://discuss.elastic.co/t/storing-a-floating-point-value-in-a-long-field-what-no-mapping-error/80238>\
**Category:** Elasticsearch\
**Created:** [March 28, 2017, 5:32am UTC](https://discuss.elastic.co/t/storing-a-floating-point-value-in-a-long-field-what-no-mapping-error/80238 "2017-03-28T05:32:20Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![GrahamHannington](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/grahamhannington/32/4404_2.png) [@GrahamHannington](https://discuss.elastic.co/u/GrahamHannington)\
**Post date:** [March 28, 2017, 5:32am UTC](https://discuss.elastic.co/t/storing-a-floating-point-value-in-a-long-field-what-no-mapping-error/80238/1 "2017-03-28T05:32:20Z")

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If I attempt to store a string value, such as `"hello"`, in a field with an existing data type (mapping) of `long`, Elasticsearch unsurprisingly reports an error (number format exception).

However, I can store a floating-point value, such as `1.5`, in a `long` field with—apparently, as far as I can tell (hence this topic)—no problem. The Elasticsearch log contains no error for this; I can get the ingested document, and the field has the original floating-point value (it hasn’t, for instance, been silently rounded or truncated to an integer).

Why doesn’t Elasticsearch report an error when I store a floating-point value in a `long` field?

What are the potential repercussions (in Elasticsearch or Kibana) of storing in Elasticsearch a floating-point value in a field that is mapped to the `long` data type?

---

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**Author:** ![cbuescher](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/cbuescher/32/60402_2.png) [@cbuescher](https://discuss.elastic.co/u/cbuescher)\
**Post date:** [March 28, 2017, 9:16am UTC](https://discuss.elastic.co/t/storing-a-floating-point-value-in-a-long-field-what-no-mapping-error/80238/2 "2017-03-28T09:16:18Z")

</div>

Hi,

Elasticsearch tries to coerce floating point values to number by default. You can turn this off by [setting the `index.mapping.coerce` setting to false](https://www.elastic.co/guide/en/elasticsearch/reference/current/coerce.html). Internally the value is truncated which you can check if you get the `doc_values` for that particular field in your index:

```auto
GET your_index/_search
{ 
    ... match your document ...,
    "docvalue_fields": ["fieldName"]
}

```

You see the "original" value in the "\_source" because we store the whole document string before any analysis takes place.

---

<div class="post-metadata">

**Author:** ![GrahamHannington](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/grahamhannington/32/4404_2.png) [@GrahamHannington](https://discuss.elastic.co/u/GrahamHannington)\
**Post date:** [March 29, 2017, 8:35am UTC](https://discuss.elastic.co/t/storing-a-floating-point-value-in-a-long-field-what-no-mapping-error/80238/3 "2017-03-29T08:35:36Z")

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Thank you for the reply, much appreciated.

As you say, if I use the search that you cite, the response contains the truncated doc value. For example, for a field that is mapped to `long`:

```
"_source" : {
  ...
  "myfield" : 3.14159
  ...
},
"fields" : {
  "myfield" : [3]
}

```

### Are the Elastic docs wrong?

From the Elastic docs for [`doc_values`](https://www.elastic.co/guide/en/elasticsearch/reference/current/doc-values.html):

> Doc values [...] store the same values as the `_source`

That statement is demonstrably false, as shown in the example response above. The doc value is `3`, but the `_source` value is `3.14159`.

Perhaps I’m still 🙂 missing something; or perhaps I’m applying a too-literal interpretation to the phrase “same values”.

Do you think that statement in the docs is correct? Or do you think it requires rewording, or qualification?

### An example

To confirm that I’ve understood what you’ve told me...

In an index where the field `myfield` is mapped to the data type `long`, I have two documents: in one document, the `_source` value of `myfield` is the integer value `12`; in the other document, the `_source` value of `myfield` is the floating-point value `12.5`.

If I send the following request:

```
GET my_index/_search
{
  "query": {
    "range" : {
      "myfield" : {
        "gte" : 12.2,
        "lte" : 12.8
      }
    }
  }
}

```

I get zero hits. That is, it doesn’t find the `12.5`.

If I’ve understood you correctly, this is because Elasticsearch is applying the query to the doc values that have been truncated due to the `long` mapping. Am I right?

### Kibana

For an index containing `_source` values for `myfield` of `3.14159`, `12`, and `12.5` , a Kibana search with `myfield` added as a column—that is, the Kibana URL specifies `columns:!(myfield)`—shows the following column values:

`3.142`  
`12.5`  
`12`

So, it seems that Kibana is displaying values from `_source` (albeit rounded to the precision specified by the default pattern for the number format), not the doc values.

However, entering the following in the search field of the Discovery page:

```
myfield:(>12 AND <13)

```

gets “No results found”, because that search is based on the doc values.

I don’t mean to try your patience—you’ve already been very helpful; thanks again—but can you shed any light on why Kibana does not show doc values? Because it seems to me there’s a disconnect between the (`_source`) values that Kibana shows and the (doc) values that are used to determine _what_ Kibana shows.

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<div class="post-metadata">

**Author:** ![cbuescher](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/cbuescher/32/60402_2.png) [@cbuescher](https://discuss.elastic.co/u/cbuescher)\
**Post date:** [March 29, 2017, 8:53am UTC](https://discuss.elastic.co/t/storing-a-floating-point-value-in-a-long-field-what-no-mapping-error/80238/4 "2017-03-29T08:53:53Z")

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> [@GrahamHannington](#):
>
> Do you think that statement in the docs is correct?

I think they are assuming you are indexing into a field with the correct type and don't do coercion (which can be turned to 'strict' as mentioned above)

> [@GrahamHannington](#):
>
> Elasticsearch is applying the query to the doc values that have been truncated due to the long mapping. Am I right?

That is correct.

> [@GrahamHannington](#):
>
> can you shed any light on why Kibana does not show doc values

I'm afraid I don't know, that question might be better answered in the kibana forum.

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<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:** [April 26, 2017, 8:53am UTC](https://discuss.elastic.co/t/storing-a-floating-point-value-in-a-long-field-what-no-mapping-error/80238/5 "2017-04-26T08:53:53Z")

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