# Prevent the loss of existing fields while using document\_id of elasticsearch output plugin

**URL:** <https://discuss.elastic.co/t/prevent-the-loss-of-existing-fields-while-using-document-id-of-elasticsearch-output-plugin/227327>\
**Category:** Logstash\
**Created:** [April 9, 2020, 1:19pm UTC](https://discuss.elastic.co/t/prevent-the-loss-of-existing-fields-while-using-document-id-of-elasticsearch-output-plugin/227327 "2020-04-09T13:19:29Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![oula\_oula](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/oula_oula/32/63182_2.png) [@oula\_oula](https://discuss.elastic.co/u/oula_oula)\
**Post date:** [April 9, 2020, 1:19pm UTC](https://discuss.elastic.co/t/prevent-the-loss-of-existing-fields-while-using-document-id-of-elasticsearch-output-plugin/227327/1 "2020-04-09T13:19:30Z")

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Hi,  
I need to inject multiple logs in a common document according to a specific field value.  
So, I specify document\_id's value in elasticsearch plugin output.

But instead of adding fields after parsing logs it deletes existing fields (made from former logs) and add the current new fields, so I lose information.  
Althought my fields has not the same name so it can't do overwritting.

How to prevent from deleting existing fields ?

---

<div class="post-metadata">

**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [April 9, 2020, 2:30pm UTC](https://discuss.elastic.co/t/prevent-the-loss-of-existing-fields-while-using-document-id-of-elasticsearch-output-plugin/227327/2 "2020-04-09T14:30:28Z")

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> [@oula\_oula](#):
>
> How to prevent from deleting existing fields ?

Use the [doc\_as\_upsert](https://www.elastic.co/guide/en/logstash/current/plugins-outputs-elasticsearch.html#plugins-outputs-elasticsearch-doc_as_upsert) option?

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<div class="post-metadata">

**Author:** ![oula\_oula](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/oula_oula/32/63182_2.png) [@oula\_oula](https://discuss.elastic.co/u/oula_oula)\
**Post date:** [April 9, 2020, 3:17pm UTC](https://discuss.elastic.co/t/prevent-the-loss-of-existing-fields-while-using-document-id-of-elasticsearch-output-plugin/227327/3 "2020-04-09T15:17:28Z")

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yes like this

```auto
output {
  elasticsearch {
    hosts => ["localhost:9200"]
	index => "test-%{+YYYY.MM.dd}"
	doc_as_upsert => true
	document_id => "doc-%{[id_essai]}"
	}
}

```

But there was no differrence using "doc\_as\_upsert = true" and "doc\_as\_upsert = false"

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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:** [May 7, 2020, 3:17pm UTC](https://discuss.elastic.co/t/prevent-the-loss-of-existing-fields-while-using-document-id-of-elasticsearch-output-plugin/227327/4 "2020-05-07T15:17:31Z")

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