# "Limits to the number of shards which are searched in parallel"

**URL:** <https://discuss.elastic.co/t/limits-to-the-number-of-shards-which-are-searched-in-parallel/120700>\
**Category:** Elasticsearch\
**Created:** [February 20, 2018, 5:52pm UTC](https://discuss.elastic.co/t/limits-to-the-number-of-shards-which-are-searched-in-parallel/120700 "2018-02-20T17:52:56Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![bobbyi](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bobbyi/32/27949_2.png) [@bobbyi](https://discuss.elastic.co/u/bobbyi)\
**Post date:** [February 20, 2018, 5:52pm UTC](https://discuss.elastic.co/t/limits-to-the-number-of-shards-which-are-searched-in-parallel/120700/1 "2018-02-20T17:52:57Z")

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The release notes for ES 6 mention:

> Limits to the number of shards which are searched in parallel, so that a single query cannot dominate the cluster.

I haven't found documentation of how this feature works. I am wondering in particular whether it is possible to raise or remove these limits.

I am working on an internal application that has many nodes and few users. It has a query that is doing an aggregation using `script` that can take time to complete and I would love for it to be able to use all of the processor cores in the cluster.

I've come across `action.search.shard_count.limit`, but that seems to be different because that is a restriction on how many shards the query can touch at all, not how many it can touch at a time.

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<div class="post-metadata">

**Author:** ![bobbyi](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/bobbyi/32/27949_2.png) [@bobbyi](https://discuss.elastic.co/u/bobbyi)\
**Post date:** [February 22, 2018, 8:19pm UTC](https://discuss.elastic.co/t/limits-to-the-number-of-shards-which-are-searched-in-parallel/120700/2 "2018-02-22T20:19:33Z")

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I found the answer. The setting is `max_concurrent_shard_requests`. It's documented here: [https://www.elastic.co/guide/en/elasticsearch/reference/current/search-search.html](https://www.elastic.co/guide/en/elasticsearch/reference/current/search-search.html) , but I missed it because it appears to be part of the section "Multi-Index, Multi-Type”.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [March 22, 2018, 8:20pm UTC](https://discuss.elastic.co/t/limits-to-the-number-of-shards-which-are-searched-in-parallel/120700/3 "2018-03-22T20:20:03Z")

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