# Perform a clear cache operation with no significant change in memory

**URL:** https://discuss.elastic.co/t/perform-a-clear-cache-operation-with-no-significant-change-in-memory/271165
**Category:** Elasticsearch
**Created:** [April 25, 2021, 3:22am UTC](https://discuss.elastic.co/t/perform-a-clear-cache-operation-with-no-significant-change-in-memory/271165 "2021-04-25T03:22:55Z")
**Posts on this page:** 6
**Page:** 1

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### Author: ![asasas234](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/asasas234/32/113152_2.png) [@asasas234](https://discuss.elastic.co/u/asasas234)
#### Post date: [April 25, 2021, 3:22am UTC](https://discuss.elastic.co/t/perform-a-clear-cache-operation-with-no-significant-change-in-memory/271165/1 "2021-04-25T03:22:55Z")

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I executed the following request to clear the cache, but when I look at the percentage of memory used by the process on top, there is no change。What is the reason for this?

curl -XPOST '[http://172.18.141.39:19200/\_cache/clear](http://172.18.141.39:19200/_cache/clear)

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### Author: ![DavidTurner](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/davidturner/32/22453_2.png) [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)
#### Post date: [April 25, 2021, 8:38am UTC](https://discuss.elastic.co/t/perform-a-clear-cache-operation-with-no-significant-change-in-memory/271165/2 "2021-04-25T08:38:10Z")

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Elasticsearch keeps hold of all the memory needed to hold the heap, even if some of it is not currently in active use.

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### Author: ![asasas234](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/asasas234/32/113152_2.png) [@asasas234](https://discuss.elastic.co/u/asasas234)
#### Post date: [April 25, 2021, 8:41am UTC](https://discuss.elastic.co/t/perform-a-clear-cache-operation-with-no-significant-change-in-memory/271165/3 "2021-04-25T08:41:01Z")

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Thanks for the answer, so how do I free the memory completely?

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### Author: ![DavidTurner](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/davidturner/32/22453_2.png) [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)
#### Post date: [April 25, 2021, 9:01am UTC](https://discuss.elastic.co/t/perform-a-clear-cache-operation-with-no-significant-change-in-memory/271165/4 "2021-04-25T09:01:22Z")

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You would have to shut Elasticsearch down. Elasticsearch only releases the memory needed to hold the heap when it exits.

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### Author: ![asasas234](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/asasas234/32/113152_2.png) [@asasas234](https://discuss.elastic.co/u/asasas234)
#### Post date: [April 25, 2021, 9:10am UTC](https://discuss.elastic.co/t/perform-a-clear-cache-operation-with-no-significant-change-in-memory/271165/5 "2021-04-25T09:10:55Z")

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> [@DavidTurner](#):
>
> You would have to shut Elasticsearch down. Elasticsearch only releases the memory needed to hold the heap when it exits.

Thanks for understanding

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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: [May 23, 2021, 9:11am UTC](https://discuss.elastic.co/t/perform-a-clear-cache-operation-with-no-significant-change-in-memory/271165/6 "2021-05-23T09:11:03Z")

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