# What is \[use\_field\_mapping\] format?

**URL:** <https://discuss.elastic.co/t/what-is-use-field-mapping-format/186416>\
**Category:** Elasticsearch\
**Created:** [June 19, 2019, 8:50am UTC](https://discuss.elastic.co/t/what-is-use-field-mapping-format/186416 "2019-06-19T08:50:55Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![simple\_commentateur](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/simple_commentateur/32/45428_2.png) [@simple\_commentateur](https://discuss.elastic.co/u/simple_commentateur)\
**Post date:** [June 19, 2019, 8:50am UTC](https://discuss.elastic.co/t/what-is-use-field-mapping-format/186416/1 "2019-06-19T08:50:55Z")

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Hi,

I have a problem with my shards failing so I check es logs.

I find this warning :

```
[instance-0000000005] [use_field_mapping] is a special format that was only used to ease the transition to 7.x. It has become the default and shouldn't be set explicitly anymore.

```

- What is concerned by this format?
- Is it has a lynk with my shards problem?

Thanks in advance

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<div class="post-metadata">

**Author:** ![simple\_commentateur](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/simple_commentateur/32/45428_2.png) [@simple\_commentateur](https://discuss.elastic.co/u/simple_commentateur)\
**Post date:** [June 20, 2019, 9:03am UTC](https://discuss.elastic.co/t/what-is-use-field-mapping-format/186416/2 "2019-06-20T09:03:34Z")

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Hi,

Any idea about this issue?

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**Author:** ![forloop](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/forloop/32/9021_2.png) [@forloop](https://discuss.elastic.co/u/forloop)\
**Post date:** [June 21, 2019, 6:04am UTC](https://discuss.elastic.co/t/what-is-use-field-mapping-format/186416/3 "2019-06-21T06:04:15Z")

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It relates to the `format` of [Doc value Fields](https://www.elastic.co/guide/en/elasticsearch/reference/6.8/search-request-docvalue-fields.html). `format` can be used to specify how a Doc value field value will be formatted in the response, useful for dates and numeric fields in particular.

`use_field_mapping` was a special format introduced in 6.x to indicate that the `format` specified in the field mapping should be the one used. Since this is now the default in 7.x, there's no need to specify it anymore, hence the warning in the logs.

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**Author:** ![yunchung](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yunchung/32/49488_2.png) [@yunchung](https://discuss.elastic.co/u/yunchung)\
**Post date:** [July 5, 2019, 8:28am UTC](https://discuss.elastic.co/t/what-is-use-field-mapping-format/186416/4 "2019-07-05T08:28:09Z")

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Hi, @forloop  
I find this warning, too.  
I write kibana plugin import `src/legacy/ui/public/styles/bootstrap/mixins.less`  
at line 88 still using 'use\_field\_mapping'

> <https://github.com/elastic/kibana/blob/v7.0.1/src/legacy/ui/public/agg_types/metrics/top_hit.js>

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<div class="post-metadata">

**Author:** ![forloop](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/forloop/32/9021_2.png) [@forloop](https://discuss.elastic.co/u/forloop)\
**Post date:** [July 5, 2019, 8:35am UTC](https://discuss.elastic.co/t/what-is-use-field-mapping-format/186416/5 "2019-07-05T08:35:48Z")

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@yunchung I would recommend [opening an issue on the Kibana repository](https://github.com/elastic/kibana/issues) to raise awareness

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [August 2, 2019, 8:35am UTC](https://discuss.elastic.co/t/what-is-use-field-mapping-format/186416/6 "2019-08-02T08:35:55Z")

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