# Elastic search: Two level nested mapping, estimate total number of documents

**URL:** <https://discuss.elastic.co/t/elastic-search-two-level-nested-mapping-estimate-total-number-of-documents/70927>\
**Category:** Elasticsearch\
**Created:** [January 9, 2017, 8:48am UTC](https://discuss.elastic.co/t/elastic-search-two-level-nested-mapping-estimate-total-number-of-documents/70927 "2017-01-09T08:48:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![nishant35](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/nishant35/32/14244_2.png) [@nishant35](https://discuss.elastic.co/u/nishant35)\
**Post date:** [January 9, 2017, 8:48am UTC](https://discuss.elastic.co/t/elastic-search-two-level-nested-mapping-estimate-total-number-of-documents/70927/1 "2017-01-09T08:48:02Z")

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I have mapping as:

```
"properties": {
  "parents": {
    "type": "nested",
    "properties": {
      "parent_id": {
        "type": "integer",
        "doc_values": false
      },
      "child": {
        "type": "nested",
        "properties": {
          "is_deleted": {
            "type": "boolean",
            "doc_values": false
          },
          "child_id": {
            "type": "integer",
            "doc_values": false
          },
          "timestamp": {
            "type": "long",
            "doc_values": false
          }
        }
      }
    }
  },
  "other_ID": {
    "type": "string",
    "index": "not_analyzed",
    "doc_values": false
  }
}

```

Each parent will have unique children i.e. there is no common child among parents.

I have assigned 5 shards (My Elastic search cluster has 7 node) to this index but **not sure if that will be sufficient**.

> Each Elasticsearch shard is a Lucene index. There is a maximum number of documents you can have in a single Lucene index. As of LUCENE-5843, the limit is 2,147,483,519 (= Integer.MAX\_VALUE - 128) documents. You can monitor shard sizes using the \_cat/shards api.

Assuming there will be say `x` unique `_ID` and each \_IDs will have `y` parents and each parent will have `z` child. what will be total document count in my index?

> To safeguard against ill-defined mappings the number of nested fields that can be defined per index has been limited to 50

Does this means that i can't have more than 50 parents in a \_ID?

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [February 6, 2017, 8:48am UTC](https://discuss.elastic.co/t/elastic-search-two-level-nested-mapping-estimate-total-number-of-documents/70927/2 "2017-02-06T08:48:20Z")

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