# Updating Vector Search of Existing Class

**URL:** <https://forum.weaviate.io/t/updating-vector-search-of-existing-class/249>\
**Category:** Support\
**Tags:** bug, developer-experience\
**Created:** [June 20, 2023, 8:18pm UTC](https://forum.weaviate.io/t/updating-vector-search-of-existing-class/249 "2023-06-20T20:18:06Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Siddhi\_Bansal](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.weaviate.io/siddhi_bansal/32/135_2.png) [@Siddhi\_Bansal](https://forum.weaviate.io/u/Siddhi_Bansal)\
**Post date:** [June 20, 2023, 8:18pm UTC](https://forum.weaviate.io/t/updating-vector-search-of-existing-class/249/1 "2023-06-20T20:18:06Z")

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Can I change the vector search process of an existing class? I believe the default is cosine, but how can I update it to dot product (for example)?

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**Author:** ![dandv](https://avatars.discourse-cdn.com/v4/letter/d/b4bc9f/32.png) [@dandv](https://forum.weaviate.io/u/dandv)\
**Post date:** [June 27, 2023, 2:51pm UTC](https://forum.weaviate.io/t/updating-vector-search-of-existing-class/249/2 "2023-06-27T14:51:43Z")

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It doesn’t make sense to change the [distance metric](https://weaviate.io/developers/weaviate/config-refs/distances) used by a class, because the [HNSW](https://weaviate.io/developers/weaviate/configuration/indexes#how-to-configure-hnsw) graph already built for the existing objects would become invalid.

Thanks for bringing this to our attention. [Weaviate should return a clear error](https://github.com/weaviate/weaviate/issues/3177) when attempting this operation.