findOne filtering by $vector returns no results

[vkarpov15]

The following query returns no results:

{
  "findOne": {
    "filter": {
      "$vector": [
        100,
        1
      ]
    },
    "options": {}
  }
}

But executing the following:

{
  "find": {
    "filter": {}
  }
}

Returns:

[
  {
    _id: new ObjectId("64ea8e193e3aec5cd0b356b2"),
    '$vector': [ 1, 100 ],
    name: 'Test vector 1',
    __v: 0
  },
  {
    _id: new ObjectId("64ea8e193e3aec5cd0b356b3"),
    '$vector': [ 100, 1 ],
    name: 'Test vector 2',
    __v: 0
  }
]

Are you able to query by exact match for $vector?

[tatu-at-datastax]

@vkarpov15 Trying this out with cqlsh I think the answer is "no" -- indexed Vector values can only be used for ANN search:

select * from vector_test where val = [1, 0.1, 0];

InvalidRequest: Error from server: code=2200 [Invalid query] message="Vector indexes only support ANN queries"

But I guess it is odd if we get no error or anything via JSON API.

I will see how this case is currently handled (via ITs) and if no error, whether we could make it fail with expressive error message.

[tatu-at-datastax]

Ok. No failure yet -- will add validation of filter, to give meaningful fail message on attempt to filter on $vector.