# Knn\_vectors field understanding

**URL:** <https://discuss.elastic.co/t/knn-vectors-field-understanding/374923>\
**Category:** Elasticsearch\
**Tags:** vector-search\
**Created:** [February 24, 2025, 7:01am UTC](https://discuss.elastic.co/t/knn-vectors-field-understanding/374923 "2025-02-24T07:01:02Z")\
**Posts on this page:** 1\
**Showing post:** 14

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**Author:** ![john-wagster](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/john-wagster/32/139021_2.png) [@john-wagster](https://discuss.elastic.co/u/john-wagster)\
**Post date:** [February 25, 2025, 10:42pm UTC](https://discuss.elastic.co/t/knn-vectors-field-understanding/374923/14 "2025-02-25T22:42:58Z")

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> Hi @john-wagster , you could reference the 1st mapping that I posted in [Dense vector field in nested object - Elastic Stack / Elasticsearch - Discuss the Elastic Stack](https://discuss.elastic.co/t/dense-vector-field-in-nested-object/375000), from which I got the index testing results here. The `file_section_text` field should consume the most amount of storage after the `file_section_embedding` field.

Ah ok so with those mappings it makes more sense. If you turn off `_source` for the dense vector field then you still have some additional fields which are contributing.

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