Search query for elasticsearch when child element is array of string

There are a several ways to solve this. Perhaps the most immediate one is to search for mumbai instead of Mumbai.

If I create the index with no mapping,

curl -XDELETE "http://localhost:9200/my_base.main_candidate/"
curl -XPUT "http://localhost:9200/my_base.main_candidate/"

then add a doc:

curl -XPUT "http://localhost:9200/my_base.main_candidate/doc/1" -d'
{
   "specific_location": {
      "location_name": "Mumbai",
      "location_tags": [
         "Mumbai"
      ],
      "tags": [
         "Mumbai"
      ]
   }
}'

then run your query with the lower-case term

curl -XPOST "http://localhost:9200/my_base.main_candidate/_search" -d'
{
   "query": {
      "filtered": {
         "query": {
            "match_all": {}
         },
         "filter": {
            "terms": {
               "specific_location.location_tags": [
                  "mumbai"
               ]
            }
         }
      }
   }
}'

I get back the expected doc:

{
   "took": 3,
   "timed_out": false,
   "_shards": {
      "total": 5,
      "successful": 5,
      "failed": 0
   },
   "hits": {
      "total": 1,
      "max_score": 1,
      "hits": [
         {
            "_index": "my_base.main_candidate",
            "_type": "doc",
            "_id": "1",
            "_score": 1,
            "_source": {
               "specific_location": {
                  "location_name": "Mumbai",
                  "location_tags": [
                     "Mumbai"
                  ],
                  "tags": [
                     "Mumbai"
                  ]
               }
            }
         }
      ]
   }
}

This is because, since no explicit mapping was used, Elasticsearch uses defaults, which means the location_tags field will be analyzed with the standard analyzer, which will convert terms to lower-case. So the term Mumbai does not exist, but mumbai does.

If you want to be able to use upper-case terms in your query, you will need to set up an explicit mapping that tells Elasticsearch not to analyze the location_tags field. Maybe something like this:

curl -XDELETE "http://localhost:9200/my_base.main_candidate/"

curl -XPUT "http://localhost:9200/my_base.main_candidate/" -d'
{
   "mappings": {
      "doc": {
         "properties": {
            "specific_location": {
               "properties": {
                  "location_tags": {
                     "type": "string",
                     "index": "not_analyzed"
                  },
                  "tags": {
                     "type": "string",
                     "index": "not_analyzed"
                  }
               }
            }
         }
      }
   }
}'

curl -XPUT "http://localhost:9200/my_base.main_candidate/doc/1" -d'
{
   "specific_location": {
      "location_name": "Mumbai",
      "location_tags": [
         "Mumbai"
      ],
      "tags": [
         "Mumbai"
      ]
   }
}'

curl -XPOST "http://localhost:9200/my_base.main_candidate/_search" -d'
{
   "query": {
      "filtered": {
         "query": {
            "match_all": {}
         },
         "filter": {
            "terms": {
               "specific_location.location_tags": [
                  "Mumbai"
               ]
            }
         }
      }
   }
}'

Here is all the above code in a handy place:

http://sense.qbox.io/gist/74844f4d779f7c2b94a9ab65fd76eb0ffe294cbb

[EDIT: by the way, I used Elasticsearch 1.3.4 when testing the above code]