# KNN Search super slow
**URL:** https://discuss.elastic.co/t/knn-search-super-slow/321631
**Category:** Elasticsearch
**Tags:** docker, vector-search
**Created:** [December 20, 2022, 10:38am UTC](https://discuss.elastic.co/t/knn-search-super-slow/321631 "2022-12-20T10:38:07Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@TopTea1](https://discuss.elastic.co/u/TopTea1)
#### Post date: [December 20, 2022, 10:38am UTC](https://discuss.elastic.co/t/knn-search-super-slow/321631/1 "2022-12-20T10:38:07Z")
Hi, I'm using ES v8.1.3 in a dockerized env with 4 shards. In my database I have around ~90M documents, and for each I have a dense vector with a dim of 768. But when I'm trying to perform a search using ANN (with cosine distance) the query takes more than 20 mins to complete. Have you any clue how to speed up this process ?
Thanks
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### Author:  [@BenTrent](https://discuss.elastic.co/u/BenTrent)
#### Post date: [December 20, 2022, 5:56pm UTC](https://discuss.elastic.co/t/knn-search-super-slow/321631/2 "2022-12-20T17:56:12Z")
Two major things:
- The KNN vectors and connections need to all be in memory.
- If you can, normalize your vectors before ingesting and use dot\_product instead of cosine.
Your vectors & connections will need `90_000_000 * (768 + 32) * 4` bytes for the vectors to sit in memory.
This will definitely require more than one node to adequately service as that is around `268gb` of ram.
Here is our overall tuning guide: [Tune approximate kNN search | Elasticsearch Guide [8.5] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/tune-knn-search.html)
We are actively making storage of vectors much more efficient. Additionally, in 8.6, we will release support for byte-value vectors so that users can quantize their floats before ingesting for HUGE space savings at minimal accuracy loss.
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### Author:  [@BenTrent](https://discuss.elastic.co/u/BenTrent)
#### Post date: [December 20, 2022, 5:57pm UTC](https://discuss.elastic.co/t/knn-search-super-slow/321631/3 "2022-12-20T17:57:03Z")
Also, there are multiple bug fixes and improvements in 8.5. I would recommend actively working towards upgrading your elasticsearch cluster version.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [January 17, 2023, 5:57pm UTC](https://discuss.elastic.co/t/knn-search-super-slow/321631/4 "2023-01-17T17:57:40Z")
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