# 100% CPU after upgrade (7.1.1 to 7.3)
**URL:** https://discuss.elastic.co/t/100-cpu-after-upgrade-7-1-1-to-7-3/194116
**Category:** Elasticsearch
**Created:** [August 6, 2019, 11:30pm UTC](https://discuss.elastic.co/t/100-cpu-after-upgrade-7-1-1-to-7-3/194116 "2019-08-06T23:30:50Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@icheishvili](https://discuss.elastic.co/u/icheishvili)
#### Post date: [August 6, 2019, 11:30pm UTC](https://discuss.elastic.co/t/100-cpu-after-upgrade-7-1-1-to-7-3/194116/1 "2019-08-06T23:30:50Z")
After upgrading to 7.3 over the weekend, I now have a node that constantly sits at full CPU utilization. \_nodes/hot\_threads is empty. The cluster has 25 indices, 250 total shards, and is made of up 3 machines, with each machine having 2 cores and 8gb of memory.
Replacing the high cpu-using node with a new machine did not fix the situation; high cpu usage came back after rebalance. Are there any known steps to fix or this is something new that was introduced in 7.3?
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### Author:  [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)
#### Post date: [August 7, 2019, 6:00am UTC](https://discuss.elastic.co/t/100-cpu-after-upgrade-7-1-1-to-7-3/194116/2 "2019-08-07T06:00:02Z")
This is surprising, particularly since hot threads is empty. Could you share the full output of the following, using something like [https://gist.github.com](https://gist.github.com) since it will be quite large.
```auto
GET _nodes/hot_threads?threads=99999&ignore_idle_threads=false
```
Another possibility is that it's busy doing GC, which won't show up in the hot threads. Can you share the last thousand lines or so of the GC log too?
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### Author:  [@icheishvili](https://discuss.elastic.co/u/icheishvili)
#### Post date: [August 7, 2019, 11:51am UTC](https://discuss.elastic.co/t/100-cpu-after-upgrade-7-1-1-to-7-3/194116/3 "2019-08-07T11:51:11Z")
Here is the hot threads output you asked for: [https://gist.github.com/icheishvili/3e7cd9382ae34c616df9e601f4771751](https://gist.github.com/icheishvili/3e7cd9382ae34c616df9e601f4771751)
And here is the last 1000 lines of gc.log: [https://gist.github.com/icheishvili/a8075376002ced072bfec2e8e3febebe](https://gist.github.com/icheishvili/a8075376002ced072bfec2e8e3febebe)
From what I can tell, GC behavior on all 3 nodes is quite similar; what caused me to check is seeing Young Allocation Failures when reading the log so I went to confirm, but happy to post more gc logs to show this.
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### Author:  [@icheishvili](https://discuss.elastic.co/u/icheishvili)
#### Post date: [August 8, 2019, 3:09pm UTC](https://discuss.elastic.co/t/100-cpu-after-upgrade-7-1-1-to-7-3/194116/4 "2019-08-08T15:09:48Z")
The misbehaving node has gotten worse and worse (up to a load avg of 20) and this has made our entire deployment unstable so we are being forced to revert back to 7.1.1. I would advise anyone reading this to carefully test 7.3.0 in their environment/traffic pattern or avoid it entirely.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [September 5, 2019, 3:09pm UTC](https://discuss.elastic.co/t/100-cpu-after-upgrade-7-1-1-to-7-3/194116/5 "2019-09-05T15:09:58Z")
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