# Where is the merge policy defined?

**URL:** <https://discuss.elastic.co/t/where-is-the-merge-policy-defined/232496>\
**Category:** Elasticsearch\
**Created:** [May 13, 2020, 6:29pm UTC](https://discuss.elastic.co/t/where-is-the-merge-policy-defined/232496 "2020-05-13T18:29:19Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![Luca\_Belluccini](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/luca_belluccini/32/33239_2.png) [@Luca\_Belluccini](https://discuss.elastic.co/u/Luca_Belluccini)\
**Post date:** [May 13, 2020, 6:59pm UTC](https://discuss.elastic.co/t/where-is-the-merge-policy-defined/232496/2 "2020-05-13T18:59:17Z")

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The documentation on the merge policy is [here](https://www.elastic.co/guide/en/elasticsearch/reference/current/index-modules-merge.html).

The merge policy is the Tiered one.  
It is not usually required to tweak settings which are not documented as they're usually necessary for special edge use cases (e.g. heavy delete use cases).

Other advanced settings are at:

- [https://github.com/elastic/elasticsearch/blob/7b34e22890e15b7480689b216c48487c87385978/server/src/main/java/org/elasticsearch/index/MergeSchedulerConfig.java#L56](https://github.com/elastic/elasticsearch/blob/7b34e22890e15b7480689b216c48487c87385978/server/src/main/java/org/elasticsearch/index/MergeSchedulerConfig.java#L56)
- [https://github.com/elastic/elasticsearch/blob/7b34e22890e15b7480689b216c48487c87385978/server/src/main/java/org/elasticsearch/index/MergePolicyConfig.java#L49](https://github.com/elastic/elasticsearch/blob/7b34e22890e15b7480689b216c48487c87385978/server/src/main/java/org/elasticsearch/index/MergePolicyConfig.java#L49)

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