POST products/_search
{
  "query": {
    "multi_match": {
      "query": "black flower dress",
      "fields": ["title", "description"],
    },
    "boost": 0.9
  },
  "knn": {
    "field": "title_vector",
    "query_vector": [0.3, 0.1, ...],
    "k": 5,
    "num_candidates": 50,
    "boost": 0.1,
    "filter": {
      "term": {
       "file_type": "jpeg"
      }
    }
  },
  "size": 20
}