elasticsearch: "More like this" combined with additional constraint

Question

I just bumped into "more like this" functionality/api. Is there a possibility to combine the result from more_like_this with some additional search constraint?

I have two following ES query which works:

POST /h/B/_search
{
   "query": {
      "more_like_this": {
         "fields": [
            "desc"
         ],
         "ids": [
            "511111260"
         ],
         "min_term_freq": 1,
         "max_query_terms": 25
      }
   }
}

Which returns

{
   "took": 16,
   "timed_out": false,
   "_shards": {
      "total": 3,
      "successful": 3,
      "failed": 0
   },
   "hits": {
      "total": 53,
      "max_score": 3.2860293,
      "hits": [
      ...

Which is fine but I need to specify additional constraint over other field of the underlying document which works separately fine:

POST /h/B/_search
{
   "query": {
      "bool": {
         "must": {
            "match": {
               "Kind": "Pen"
            }
         }
      }
   }
}

I would love to combine those two to one, as the query should state: "Find a similar items to items labelled with Pen". I tried following with nested query but that gives me some error back:

POST /h/B/_search
{
   "query": {
      "more_like_this": {
         "fields": [
            "desc"
         ],
         "ids": [
            "511111260"
         ],
         "min_term_freq": 1,
         "max_query_terms": 25
      },
      "nested": {
         "query": {
            "bool": {
               "must": {
                  "match": {
                     "Kind": "Pen"
                  }
               }
            }
         }
      }
   }
}

I tried several variant for combining those two search criteria but so far with no luck. If someone more experienced could provide some hint that would be really appreciated.

Thanks

Answer 1

bool queries are used exactly for this purpose. A bool must is basically equivalent to the Boolean AND operation. Similarly you can use bool should for Boolean OR and bool must_not for Boolean NOT operations.

POST /h/B/_search
{
   "query": {
      "bool": {
         "must": [
            {
               "more_like_this": {
                  "fields": [
                     "desc"
                  ],
                  "ids": [
                     "511111260"
                  ],
                  "min_term_freq": 1,
                  "max_query_terms": 25
               }
            },
            {
               "match": {
                  "Kind": "Pen"
               }
            }
         ]
      }
   }
}