# Performance after 5.6 -\> 6.2 upgrade

**URL:** <https://discuss.elastic.co/t/performance-after-5-6-6-2-upgrade/134032>\
**Category:** Elasticsearch\
**Created:** [May 31, 2018, 11:15am UTC](https://discuss.elastic.co/t/performance-after-5-6-6-2-upgrade/134032 "2018-05-31T11:15:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Petr\_Novotny](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/petr_novotny/32/16438_2.png) [@Petr\_Novotny](https://discuss.elastic.co/u/Petr_Novotny)\
**Post date:** [May 31, 2018, 11:15am UTC](https://discuss.elastic.co/t/performance-after-5-6-6-2-upgrade/134032/1 "2018-05-31T11:15:48Z")

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Hi,

I upgraded our cluster from 5.6 to 6.2.4 and search performance went down, especially in aggregations, which we use quite heavily. This is how the cluster monitoring data looks like:

 ![es6perf](https://us1.discourse-cdn.com/elastic/original/3X/a/9/a9b409167a56d90e7fbc934b8d04da3363e733d2.jpg)

As you can see, Heap and GC raised up, I can also see messages about long GC in cluster logs:  
[gc][209581] overhead, spent [4.1s] collecting in the last [4.2s]

We have cluster of 8 nodes, each with 16GB RAM with 8GB heap.

Any ideas what to look for?🙂 thank you

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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:** [June 28, 2018, 11:15am UTC](https://discuss.elastic.co/t/performance-after-5-6-6-2-upgrade/134032/2 "2018-06-28T11:15:58Z")

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