inner hits: huge number in "size" makes node go OOM even with very few docs

[brwe]

spin off from https://discuss.elastic.co/t/difficulty-in-formulating-query-for-my-usecase/28773/4

The below example will make elasticsearch 1.7.1 OOM. I assume this is similar to #12510 ?

DELETE testidx

PUT testidx
{
  "mappings": {
    "doc": {
      "properties": {
        "inner_hits": {
          "type": "nested"
        }
      }
    }
  }
}

POST testidx/doc
{
  "Language": [
    "English"
  ],
  "Tags": [
    "MT",
    "MUMBAI",
    "CHEN"
  ],
  "_boost": 3,
  "inner_hits": [
    {
      "Code": "ET00009709",
      "IsDefault": "",
      "Language": "English",
      "Format": "3D",
      "Region": "MUMBAI"
    },
    {
      "Code": "ET00009710",
      "IsDefault": "Y",
      "Language": "English",
      "Format": "2D",
      "Region": "CHEN"
    },
    {
      "Code": "ET00009713",
      "IsDefault": "",
      "Language": "Hindi",
      "Format": "2D",
      "Region": "MUMBAI"
    },
    {
      "Code": "ET00009714",
      "IsDefault": "",
      "Language": "Tamil",
      "Format": "3D",
      "Region": "MUMBAI"
    },
    {
      "Code": "ET00009715",
      "IsDefault": "",
      "Language": "Hindi",
      "Format": "3D",
      "Region": "MUMBAI"
    },
    {
      "Code": "ET00009716",
      "IsDefault": "",
      "Language": "Bengali",
      "Format": "2D",
      "Region": "MUMBAI"
    }
  ]
}

POST testidx/_search
{
  "fields": [], 
  "query": {
    "nested": {
      "path": "inner_hits",
      "query": {
        "match": {
          "Region": "MUMBAI"
        }
      },
      "inner_hits": {
        "size": 100000000
      }
    }
  }
}

[martijnvg]

@brwe Yes, this is similar to #12510 and should be solved in the same as was done in top_hits aggregator.

[clintongormley]

will also be helped by #13188