# Config '\_id' generation

**URL:** <https://discuss.elastic.co/t/config--id-generation/51860>\
**Category:** Logstash\
**Created:** [June 4, 2016, 4:18pm UTC](https://discuss.elastic.co/t/config--id-generation/51860 "2016-06-04T16:18:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![evgeniy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/evgeniy/32/137942_2.png) [@evgeniy](https://discuss.elastic.co/u/evgeniy)\
**Post date:** [June 4, 2016, 4:18pm UTC](https://discuss.elastic.co/t/config--id-generation/51860/1 "2016-06-04T16:18:33Z")

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Hi all,

How I can set what fields to use in '\_id' generation?

I use logstash to fetch log files from different places. Sometimes those files are identical. So I want to prevent elasticsearch from adding dublicated log entries. As I understand, if system discover the same id, entry will not be added (or replaced - it does not matter). The simplest way to do this - exclude from '\_id' generation path field. So how I can set what fields to use to generate '\_id'?

Thanks,  
Evgeniy

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**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [June 5, 2016, 6:50am UTC](https://discuss.elastic.co/t/config--id-generation/51860/2 "2016-06-05T06:50:17Z")

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Do that in LS, set the `document_id` value - [https://www.elastic.co/guide/en/logstash/current/plugins-outputs-elasticsearch.html#plugins-outputs-elasticsearch-document\_id](https://www.elastic.co/guide/en/logstash/current/plugins-outputs-elasticsearch.html#plugins-outputs-elasticsearch-document_id)

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**Author:** ![evgeniy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/evgeniy/32/137942_2.png) [@evgeniy](https://discuss.elastic.co/u/evgeniy)\
**Post date:** [June 5, 2016, 8:56pm UTC](https://discuss.elastic.co/t/config--id-generation/51860/3 "2016-06-05T20:56:31Z")

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Thank you very much! It's work! You are greate! 🙂👍

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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:** [July 6, 2017, 4:54am UTC](https://discuss.elastic.co/t/config--id-generation/51860/4 "2017-07-06T04:54:28Z")

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