# Node stats API overhead

**URL:** <https://discuss.elastic.co/t/node-stats-api-overhead/204186>\
**Category:** Elasticsearch\
**Tags:** rally\
**Created:** [October 18, 2019, 8:39am UTC](https://discuss.elastic.co/t/node-stats-api-overhead/204186 "2019-10-18T08:39:05Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dbakti7](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dbakti7/32/42250_2.png) [@dbakti7](https://discuss.elastic.co/u/dbakti7)\
**Post date:** [October 18, 2019, 8:39am UTC](https://discuss.elastic.co/t/node-stats-api-overhead/204186/1 "2019-10-18T08:39:05Z")

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According to [Telemetry Devices - Rally 2.10.0 documentation](https://esrally.readthedocs.io/en/stable/telemetry.html#node-stats)  
It's mentioned that

> Using this telemetry device will skew your results because the node-stats API triggers additional refreshes.

What "refreshes" refers to here? Index refresh?  
There is no warning or information about this in the [API documentation](https://www.elastic.co/guide/en/elasticsearch/reference/current/cluster-nodes-stats.html#cluster-nodes-stats-api-request)  
I'm trying to understand what's the actual overhead of calling this API. For example, whether it's okay to poll this API every X ms to plot the graph of metrics reported there.  
Thank you!

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**Author:** ![dliappis](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dliappis/32/56174_2.png) [@dliappis](https://discuss.elastic.co/u/dliappis)\
**Post date:** [October 18, 2019, 5:05pm UTC](https://discuss.elastic.co/t/node-stats-api-overhead/204186/2 "2019-10-18T17:05:33Z")

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Hello,

Yes this refers to the same refreshes as the ones you can explicitly trigger from the [\_refresh](https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-refresh.html) api.

However since [this PR](https://github.com/elastic/elasticsearch/pull/40458) i.e. since Elasticsearch version 7.2.0 this behavior has been notified and shouldn't be causing a refresh "storm" when hitting this api frequently.

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<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:** [November 15, 2019, 5:21pm UTC](https://discuss.elastic.co/t/node-stats-api-overhead/204186/3 "2019-11-15T17:21:08Z")

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Closed on November 15, 2019, 5:21pm UTC

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