Support vector distance cutoff queries

[cevian]

Right now we only support ORDER BY distance queries. We should add support for WHERE distance <0.6 queries too.

[Drzhivago264]

Hello, dont know if I am doing something stupid, but currently I am using this to achieve distance cutoff.

SELECT *, embedding <=> %s as distance FROM server_embeddingdatasetrecord  
WHERE embedding <=> %s < %s AND dataset_id = %s
ORDER BY distance  
LIMIT %s;

Again, if there is anyone there, a better documentation is very helpful for those who dont have much knowledge about sql and vector indexing.

[Mickael-van-der-Beek]

@Drzhivago264 Instinctively, I would say that your WHERE condition isn't going to use the PGVectorSpace DiskANN index and will have to scan the entire table to find the matching rows.

There might be an index on dataset_id which could pre-filter the rows but that would unrelated to the vectors.

[Mickael-van-der-Beek]

@cevian I can confirm that this could be very handy indeed. We have a few uses cases where the number of results is undefined and all matching results within a certain distance or similarity should be returned.

We currently have not found a great solution for this.