# Modify field type when merging index

**URL:** <https://discuss.elastic.co/t/modify-field-type-when-merging-index/221053>\
**Category:** Elasticsearch\
**Created:** [February 26, 2020, 2:08pm UTC](https://discuss.elastic.co/t/modify-field-type-when-merging-index/221053 "2020-02-26T14:08:27Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Norman\_Khine](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/norman_khine/32/3342_2.png) [@Norman\_Khine](https://discuss.elastic.co/u/Norman_Khine)\
**Post date:** [February 26, 2020, 2:08pm UTC](https://discuss.elastic.co/t/modify-field-type-when-merging-index/221053/1 "2020-02-26T14:08:27Z")

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Hello,  
I am trying to merge daily indexes into monthly indexes, but I get some errors like

```auto
"reason":"mapper [event.data.playback.progress] cannot be changed from type [long] to [float]"},"status":400}

```

In my application, I know the type for example event.data.playback.progress should be [long], so is there a way to convert this when importing the document so it has the correct type?

any advice is much appreciated

---

<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:** [March 25, 2020, 2:08pm UTC](https://discuss.elastic.co/t/modify-field-type-when-merging-index/221053/2 "2020-03-25T14:08:31Z")

</div>

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