# Is it not possible to discover an underscore mapping?

**URL:** <https://forum.opensearch.org/t/is-it-not-possible-to-discover-an-underscore-mapping/14740>\
**Category:** OpenSearch Dashboards\
**Created:** [June 20, 2023, 5:53am UTC](https://forum.opensearch.org/t/is-it-not-possible-to-discover-an-underscore-mapping/14740 "2023-06-20T05:53:22Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![jtwalters](https://avatars.discourse-cdn.com/v4/letter/j/3e96dc/32.png) [@jtwalters](https://forum.opensearch.org/u/jtwalters)\
**Post date:** [June 20, 2023, 5:53am UTC](https://forum.opensearch.org/t/is-it-not-possible-to-discover-an-underscore-mapping/14740/1 "2023-06-20T05:53:22Z")

</div>

**Version** : AWS v2.5.0 (OpenSearch\_2\_5\_R20230308-P4)

**Describe the issue** : If you create a mapping with a value like “\_anyname” you can’t filter the documents by the value in the Discovery. And also you will see it in the left panel with an “ask mark (?)”:

![image](https://us1.discourse-cdn.com/flex019/uploads/mauve_hedgehog/original/2X/b/b3c596dcaf6b93c10490d34e320bd8efb9543ed0.png)

In case you try force the search by editing DSL the filter will be created like “ **\_anyname: Error** ” and don’t filter anything. The DSL query that I am using:

```auto
Query DSL:
{
  "query": {
    "match_phrase": {
      "_manualParse": true
    }
  }
}

```

But you could filter the values using the DevTools using the following query:

```auto
GET <index>/_search
{
  "size": 1,
  "query": {
    "match": {
      "_manualParse": true
    }
  }
}

```

So, I think the underscore make a kind “special” mapping, but is this mentioned in the documentation? Also, is it possible to enable filters in the Discovery?

---

<div class="post-metadata">

**Author:** ![pablo](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.opensearch.org/pablo/32/10363_2.png) [@pablo](https://forum.opensearch.org/u/pablo)\
**Post date:** [June 21, 2023, 4:10pm UTC](https://forum.opensearch.org/t/is-it-not-possible-to-discover-an-underscore-mapping/14740/2 "2023-06-21T16:10:35Z")

</div>

@jtwalters I’ve just tested your scenario and got this message in Discovery

![image](https://us1.discourse-cdn.com/flex019/uploads/mauve_hedgehog/original/2X/d/d7c9037114a4282012d6776640cfdd9292c0d358.png)

As you can see in the screenshot below the field doesn’t appear in the index pattern definition.

 ![image](https://us1.discourse-cdn.com/flex019/uploads/mauve_hedgehog/original/2X/4/4b7e99154382437d323070180fbe263100443e14.png)

As per next screenshot this field can’t be indexed, therefore can’t be searched in the Discovery

![image](https://us1.discourse-cdn.com/flex019/uploads/mauve_hedgehog/original/2X/e/ee7f8144716541eb8f1f58921799b10f2e9e3d97.png)

You could report it in GitHub as missing information in OpenSearch documentation.