# Stop-the-world slow GC's all the time \[Production\]

**URL:** <https://discuss.elastic.co/t/stop-the-world-slow-gcs-all-the-time-production/43602>\
**Category:** Elasticsearch\
**Created:** [March 6, 2016, 5:18pm UTC](https://discuss.elastic.co/t/stop-the-world-slow-gcs-all-the-time-production/43602 "2016-03-06T17:18:42Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![dorr](https://avatars.discourse-cdn.com/v4/letter/d/d2c977/32.png) [@dorr](https://discuss.elastic.co/u/dorr)\
**Post date:** [March 6, 2016, 5:18pm UTC](https://discuss.elastic.co/t/stop-the-world-slow-gcs-all-the-time-production/43602/1 "2016-03-06T17:18:42Z")

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Hello.  
I have a single server with 32 GB RAM and 24 cores.  
ElasticSearch has 16GB out of it, set in ES\_HEAP\_SIZE.  
Total index size is ~200 GB. Not using doc values.

ElasticSearch 1.7  
Java version:  
`openjdk version "1.8.0_66-internal" OpenJDK Runtime Environment (build 1.8.0_66-internal-b17) OpenJDK 64-Bit Server VM (build 25.66-b17, mixed mode)`

Upon checking, I see that the fielddata cache size is 4 GB and filter cache size is 1.2 GB.  
So where do the rest of the 10.8 GB go to?

I'm getting these GC logs:  
`[2016-03-06 16:38:56,632][WARN][monitor.jvm] [Scarlet Witch] [gc][old][6317][367] duration [23.5s], collections [2]/[24.1s], total [23.5s]/[1.5h], memory [15.7gb]->[14.7gb]/[15.8gb], all_pools {[young] [1.1gb]->[176.2mb]/[1.1gb]}{[survivor] [14.3mb]->[0b]/[149.7mb]}{[old] [14.5gb]->[14.5gb]/[14.5gb]} [2016-03-06 16:39:44,043][WARN][monitor.jvm] [Scarlet Witch] [gc][old][6343][369] duration [22.2s], collections [1]/[22.3s], total [22.2s]/[1.5h], memory [15.7gb]->[14.7gb]/[15.8gb], all_pools {[young] [1.1gb]->[184.4mb]/[1.1gb]}{[survivor] [87mb]->[0b]/[149.7mb]}{[old] [14.5gb]->[14.5gb]/[14.5gb]} [2016-03-06 16:40:31,584][WARN][monitor.jvm] [Scarlet Witch] [gc][old][6369][371] duration [22.4s], collections [1]/[22.4s], total [22.4s]/[1.5h], memory [15.8gb]->[14.7gb]/[15.8gb], all_pools {[young] [1.1gb]->[188.5mb]/[1.1gb]}{[survivor] [136.4mb]->[0b]/[149.7mb]}{[old] [14.5gb]->[14.5gb]/[14.5gb]}`  
And many more, repeating.  
It seems the Garbage Collector can't get rid of some things there.  
What are they?  
How can I prevent this?

Thanks!

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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:** [March 6, 2016, 8:20pm UTC](https://discuss.elastic.co/t/stop-the-world-slow-gcs-all-the-time-production/43602/2 "2016-03-06T20:20:29Z")

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If you _really_ want to know then take a heap dump and analyse it.  
Do you have Marvel installed on this?

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**Author:** ![dorr](https://avatars.discourse-cdn.com/v4/letter/d/d2c977/32.png) [@dorr](https://discuss.elastic.co/u/dorr)\
**Post date:** [March 7, 2016, 10:25am UTC](https://discuss.elastic.co/t/stop-the-world-slow-gcs-all-the-time-production/43602/3 "2016-03-07T10:25:27Z")

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I'm not sure a heap dump would help me as I'm not familiar with the internals.  
I do have Marvel installed.  
Is there any specific metric that could point to the cause of the GCs?

Here's a link: [PDF printout from Marvel](https://drive.google.com/file/d/0BzX1rWUSoo56dTZuSnBBQ1JyMm8/view?usp=sharing)

Thanks!

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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:** [July 5, 2017, 11:10pm UTC](https://discuss.elastic.co/t/stop-the-world-slow-gcs-all-the-time-production/43602/4 "2017-07-05T23:10:45Z")

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