# Is this an error in documentation of "numeric\_detection"
**URL:** https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944
**Category:** Elasticsearch
**Created:** [December 17, 2020, 6:14am UTC](https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944 "2020-12-17T06:14:39Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@pk.241011](https://discuss.elastic.co/u/pk.241011)
#### Post date: [December 17, 2020, 6:14am UTC](https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944/1 "2020-12-17T06:14:40Z")
Hi,
I was going through the documentation of [Dynamic Field Mapping](https://www.elastic.co/guide/en/elasticsearch/reference/current/dynamic-field-mapping.html).
In the table I see the last entry:
**JSON data type**....................................... **Elasticsearch data type**
string........................................................ Either a [`date`](https://www.elastic.co/guide/en/elasticsearch/reference/current/date.html) field (if the value passes [date detection](https://www.elastic.co/guide/en/elasticsearch/reference/current/dynamic-field-mapping.html#date-detection)), a [`double`](https://www.elastic.co/guide/en/elasticsearch/reference/current/number.html) or [`long`](https://www.elastic.co/guide/en/elasticsearch/reference/current/number.html) field (if the value passes [numeric detection](https://www.elastic.co/guide/en/elasticsearch/reference/current/dynamic-field-mapping.html#numeric-detection)) or a [`text`](https://www.elastic.co/guide/en/elasticsearch/reference/current/text.html) field, with a [`keyword`](https://www.elastic.co/guide/en/elasticsearch/reference/current/keyword.html) sub-field.
My understanding is that the default will be double or long.
However in the same page later on, the section on [Numeric Detection](https://www.elastic.co/guide/en/elasticsearch/reference/current/dynamic-field-mapping.html#numeric-detection) has an example where it is said:
The `my_float` field is added as a [`float`](https://www.elastic.co/guide/en/elasticsearch/reference/current/number.html) field.
It mapped it as a float instead of double.
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [December 21, 2020, 3:16am UTC](https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944/2 "2020-12-21T03:16:24Z")
> [@pk.241011](#):
>
> My understanding is that the default will be double or long.
It depends on what is detected.
> [@pk.241011](#):
>
> The `my_float` field is added as a [`float`](https://www.elastic.co/guide/en/elasticsearch/reference/current/number.html) field.
>
> It mapped it as a float instead of double.
Again, it depends on what is detected.
---
### Author:  [@pk.241011](https://discuss.elastic.co/u/pk.241011)
#### Post date: [December 21, 2020, 4:18am UTC](https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944/3 "2020-12-21T04:18:36Z")
Hi Mark,
Here is what the [documentation](https://www.elastic.co/guide/en/elasticsearch/reference/current/number.html) is saying on the numeric types:
long -\> A signed 64-bit **integer**
double -\> A double-precision 64-bit IEEE 754 **floating** point number
float -\> A single-precision 32-bit IEEE 754 floating point number
And it is here I am getting confused. It should have detected it as a long or double. But it detected it as **float**.
Should the documentation for Dynamic field mapping say that it can be detected as long, double or float?
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [December 21, 2020, 4:19am UTC](https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944/4 "2020-12-21T04:19:56Z")
It's picked the smallest "size" mapping for the provided `my_float` value, which is a float.
---
### Author:  [@pk.241011](https://discuss.elastic.co/u/pk.241011)
#### Post date: [December 21, 2020, 4:33am UTC](https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944/5 "2020-12-21T04:33:49Z")
The documentation is saying:
string -\> Either a date field (if the value passes date detection), **a double or long field** (if the value passes numeric detection) or a text field, with a keyword sub-field.
There is no mention of the fact that it will strive to choose the smallest "size".
I know it might look like splitting the hair but I am getting tripped with error
`Bad Request: [status_exception] cannot merge mappings because of differences for field`
while creating a Analytics Job.
The data is monthly data and I see that for some months the data is mapped a double and for others as float. Hence the question.
---
### Author:  [@warkolm](https://discuss.elastic.co/u/warkolm)
#### Post date: [December 21, 2020, 4:50am UTC](https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944/6 "2020-12-21T04:50:57Z")
If you are using dynamic mapping then there may be some differences as Elasticsearch tries to do its best, but it's not guaranteed to be consistent.
Sounds like you should use a mapping template instead.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [January 18, 2021, 4:50am UTC](https://discuss.elastic.co/t/is-this-an-error-in-documentation-of-numeric-detection/258944/7 "2021-01-18T04:50:58Z")
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