# \_id field duplication after data copy to new index

**URL:** https://discuss.elastic.co/t/id-field-duplication-after-data-copy-to-new-index/135497
**Category:** Elasticsearch
**Created:** [June 12, 2018, 9:44am UTC](https://discuss.elastic.co/t/id-field-duplication-after-data-copy-to-new-index/135497 "2018-06-12T09:44:42Z")
**Posts on this page:** 2
**Page:** 1

<div class="post-metadata">

### Author: ![hardik\_bhalodia](https://avatars.discourse-cdn.com/v4/letter/h/e95f7d/32.png) [@hardik\_bhalodia](https://discuss.elastic.co/u/hardik_bhalodia)
#### Post date: [June 12, 2018, 9:44am UTC](https://discuss.elastic.co/t/id-field-duplication-after-data-copy-to-new-index/135497/1 "2018-06-12T09:44:42Z")

</div>

Hi Community

We have one index with documents. We are planning to copy these documents to new index.  
But we are worried about \_id field.

Old index \_id will be copied as it is to new index but what will happen when new document is indexed in new index? Is there a chance that new index generate same \_id and document get updated instead of create?

Regards,  
Hardik

---

<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: [July 10, 2018, 9:56am UTC](https://discuss.elastic.co/t/id-field-duplication-after-data-copy-to-new-index/135497/2 "2018-07-10T09:56:28Z")

</div>

This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.