Find missing documents in index by id field

[ansamHox]

I've imported over 250 millions documents in Elasticsearch from Oracle via Logstash and 45 docs hasn't been imported. Count on ES and count on ORA are not the same. I want to check which documents are missing. My doc_id is one parameter that is unique and it is increasing by 1 always. So, If my first document was 100000001, the next one is 100000002 and so on. Idea is to check which doc_ids are missing by increasing starting number by 1 and print doc_id-s of missing docs. I'm not quite sure am I using the correct script because my doc_id is a number but it's mapped like text so I need to convert it to a number also. Here's what I tried (Elasticsearch is 2.3):

GET /my_index/my_type/_search
{
  "size": 0,
  "aggs": {
    "find_missing_ids": {
      "histogram": {
        "field": "my_id",  #text type - need to convert to Int/long
        "interval": 1,
        "min_doc_count": 0
      },
      "aggs": {
        "remove_existing_bucket_selector": {
          "bucket_selector": {
            "buckets_path": {
              "count": "_count"
            },
            "script": {
              "inline": "count == 0",
              "lang": "expression"
            }
          }
        }
      }
    }
  }
}

How can I cast my_id field to number, because when I try to add this to script:

"script": {
              "inline": "if (doc.containsKey('my_id')) { if (doc['my_id.value'] != null) {	return Integer.parseInt(doc['my_id'].value) }}", 
              "lang": "expression"

I get

{
"type": "json_parse_exception",
"reason": "json_parse_exception: Illegal unquoted character ((CTRL-CHAR, code 9)): has to be escaped using backslash to be included in string value\n at [Source: [B@18d4b515; line: 17, column: 100]"

Mapping for id field is

           "my_id": {
            "type": "string",
            "index": "not_analyzed"