# I forgot to index a field **URL:** \ **Category:** Elasticsearch\ **Created:** [July 25, 2021, 7:44am UTC](https://discuss.elastic.co/t/i-forgot-to-index-a-field/279552 "2021-07-25T07:44:13Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Zongxian\_Feng](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zongxian_feng/32/91488_2.png) [@Zongxian\_Feng](https://discuss.elastic.co/u/Zongxian_Feng)\ **Post date:** [July 25, 2021, 7:44am UTC](https://discuss.elastic.co/t/i-forgot-to-index-a-field/279552/1 "2021-07-25T07:44:13Z")
Hi. I forgot to index a field called "n\_citation" which is in type "integer". When mapping the dataset, I decide to map the necessary fields (like "title" and "abstract") only to save my time. Now, it turns out that the "n\_citation" field is important(maybe the most important field). I have 500GB dataset to map. What should I do now? Is there a quick way to reindex it? ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [July 25, 2021, 9:27am UTC](https://discuss.elastic.co/t/i-forgot-to-index-a-field/279552/2 "2021-07-25T09:27:53Z")
If the field is not part of the `_source` document yet, you need to reindex everything from the source as you initially did it. If the field is part of it, you can may be use the `_reindex` API and just change the target index mapping. ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [August 22, 2021, 1:04pm UTC](https://discuss.elastic.co/t/i-forgot-to-index-a-field/279552/4 "2021-08-22T13:04:54Z")
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