# Refresh interval setting on old indices

**URL:** <https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075>\
**Category:** Elasticsearch\
**Created:** [October 26, 2018, 12:57am UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075 "2018-10-26T00:57:47Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![ben5556](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ben5556/32/101629_2.png) [@ben5556](https://discuss.elastic.co/u/ben5556)\
**Post date:** [October 26, 2018, 12:57am UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075/1 "2018-10-26T00:57:47Z")

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Hi,

If refresh interval on an old unchanging index/ indices is set to 5s, does refresh still happen for the index/ indices every 5 seconds ? Will changing the refresh interval setting to 30s on old indices improve performance ?

What happens if we set refresh interval to -1 on old indices that never change ?

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**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [October 26, 2018, 1:01am UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075/2 "2018-10-26T01:01:30Z")

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> [@ben5556](#):
>
> If refresh interval on an old unchanging index/ indices is set to 5s, does refresh still happen for the index/ indices every 5 seconds ?

Yes.

> [@ben5556](#):
>
> Will changing the refresh interval setting to 30s on old indices improve performance ?

Not likely as they are, usually, finished reading.

> [@ben5556](#):
>
> What happens if we set refresh interval to -1 on old indices that never change ?

Then it will never refresh.

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<div class="post-metadata">

**Author:** ![ben5556](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ben5556/32/101629_2.png) [@ben5556](https://discuss.elastic.co/u/ben5556)\
**Post date:** [October 26, 2018, 1:09am UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075/3 "2018-10-26T01:09:13Z")

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If it never refreshes what will be the impact on an index that never changes ?

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<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [October 26, 2018, 1:18am UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075/4 "2018-10-26T01:18:47Z")

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Technically, nothing.

But if nothing changes, then leaving it to refresh, even at a longer period, incurs no cost and has no real downside. So you're probably better off leaving it on.

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<div class="post-metadata">

**Author:** ![ben5556](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ben5556/32/101629_2.png) [@ben5556](https://discuss.elastic.co/u/ben5556)\
**Post date:** [October 26, 2018, 1:31am UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075/5 "2018-10-26T01:31:18Z")

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Thanks!

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<div class="post-metadata">

**Author:** ![jmartori](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jmartori/32/36981_2.png) [@jmartori](https://discuss.elastic.co/u/jmartori)\
**Post date:** [October 26, 2018, 1:56pm UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075/6 "2018-10-26T13:56:39Z")

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And what if the index was still being read, in order to generate long term reports?

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<div class="post-metadata">

**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\
**Post date:** [October 27, 2018, 12:38am UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075/7 "2018-10-27T00:38:17Z")

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Reads would only care about refreshes if there is data waiting to be flushed, ie if the index is being written to.

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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:** [November 24, 2018, 12:38am UTC](https://discuss.elastic.co/t/refresh-interval-setting-on-old-indices/154075/8 "2018-11-24T00:38:17Z")

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