# The consequences of manually changing the mapping of the destination index after reindexing has started

**URL:** <https://discuss.elastic.co/t/the-consequences-of-manually-changing-the-mapping-of-the-destination-index-after-reindexing-has-started/301245>\
**Category:** Elasticsearch\
**Tags:** reindex\
**Created:** [March 31, 2022, 6:33pm UTC](https://discuss.elastic.co/t/the-consequences-of-manually-changing-the-mapping-of-the-destination-index-after-reindexing-has-started/301245 "2022-03-31T18:33:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Lala\_D](https://avatars.discourse-cdn.com/v4/letter/l/b5e925/32.png) [@Lala\_D](https://discuss.elastic.co/u/Lala_D)\
**Post date:** [March 31, 2022, 6:33pm UTC](https://discuss.elastic.co/t/the-consequences-of-manually-changing-the-mapping-of-the-destination-index-after-reindexing-has-started/301245/1 "2022-03-31T18:33:46Z")

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Hello everyone!

I am new to Elasticsearch and will highly appreciate any reply.

My task is to do reindexing.  
Without configuring settings, mappings or even creating the destination index, I started reindexing straight away. Later when some portion of documents had already been reindexed I realized the mapping of the destination index (which Elasticsearch automatically created since I didn't create mapping explicitly ) lacks one field called "oban\_job".

So my questions are:

1. How come Elasticsearch left out "oban\_job" field in the mapping of the destination index? And how is it possible that no errors occurred during reindexing process given that one field of the source index was absent in the destination index?

2. If I manually add "oban\_job" field with its corresponding type into the mapping of destination index will I have to delete all the documents that have already been reindexed and start reindexing from scratch or no need for deleting?

Thank you in advance!

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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:** [April 4, 2022, 12:42am UTC](https://discuss.elastic.co/t/the-consequences-of-manually-changing-the-mapping-of-the-destination-index-after-reindexing-has-started/301245/2 "2022-04-04T00:42:34Z")

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Welcome to our community! 😃

1. You'd need to share more information for us to provide comments. Mappings, the reindex request etc
2. Either that or do an update by query

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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:** [May 2, 2022, 12:43am UTC](https://discuss.elastic.co/t/the-consequences-of-manually-changing-the-mapping-of-the-destination-index-after-reindexing-has-started/301245/3 "2022-05-02T00:43:02Z")

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