# Fuzzy query in query vs. filter context

**URL:** <https://discuss.elastic.co/t/fuzzy-query-in-query-vs-filter-context/125823>\
**Category:** Elasticsearch\
**Created:** [March 27, 2018, 9:05pm UTC](https://discuss.elastic.co/t/fuzzy-query-in-query-vs-filter-context/125823 "2018-03-27T21:05:16Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![l\_l](https://avatars.discourse-cdn.com/v4/letter/l/f0a364/32.png) [@l\_l](https://discuss.elastic.co/u/l_l)\
**Post date:** [March 27, 2018, 9:05pm UTC](https://discuss.elastic.co/t/fuzzy-query-in-query-vs-filter-context/125823/1 "2018-03-27T21:05:16Z")

</div>

I have an index whose documents have a field `firstName`. If I run the following, for example:

```
GET _search/
{
  "query": {
    "fuzzy": {
      "firstName": {
        "value": "yvonne",
        "fuzziness": 1
      }
    }
  }
}

```

I get 5596 hits. Now if I stick the fuzzy term inside a bool must clause:

```
GET _search/
{
  "query": {
    "bool": {
      "must": [
        {
          "fuzzy": {
            "firstName": {
              "value": "yvonne",
              "fuzziness": 1
            }
          }
        }
      ]
    }
  }
}

```

I still get 5596. And if I change the must to a filter clause:

```
GET _search/
{
  "query": {
    "bool": {
      "filter": [
        {
          "fuzzy": {
            "firstName": {
              "value": "yvonne",
              "fuzziness": 1
            }
          }
        }
      ]
    }
  }
}

```

Same, 5596 again.

Ok, now I change `fuzziness` to 2 instead of 1. Running the simple fuzzy term query again:

```
GET _search/
{
  "query": {
    "fuzzy": {
      "firstName": {
        "value": "yvonne",
        "fuzziness": 2
      }
    }
  }
}

```

Now I get 6079 hits. Larger edit distance should match more documents, seems reasonable. Now stick that inside a bool query as a must clause again:

```
GET _search/
{
  "query": {
    "bool": {
      "must": [
        {
          "fuzzy": {
            "firstName": {
              "value": "yvonne",
              "fuzziness": 2
            }
          }
        }
      ]
    }
  }
}

```

Still 6079. Now change the must clause to a filter:

```
GET _search/
{
  "query": {
    "bool": {
      "filter": [
        {
          "fuzzy": {
            "firstName": {
              "value": "yvonne",
              "fuzziness": 2
            }
          }
        }
      ]
    }
  }
}

```

This returns _7980_ hits.

As I understand it, the sole difference between must and filter clauses in a bool query is whether hits are scored or not. But this doesn't seem to be true; running the fuzzy query in a filter context seems to be making the query less selective. I can't seem to find anything in the Elastic docs to explain this behavior. What am I missing? Thanks in advance.

---

<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:** [April 24, 2018, 9:05pm UTC](https://discuss.elastic.co/t/fuzzy-query-in-query-vs-filter-context/125823/2 "2018-04-24T21:05:27Z")

</div>

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