# Do full gc frequently?

**URL:** <https://discuss.elastic.co/t/do-full-gc-frequently/67084>\
**Category:** Elasticsearch\
**Created:** [November 24, 2016, 10:25am UTC](https://discuss.elastic.co/t/do-full-gc-frequently/67084 "2016-11-24T10:25:05Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![famoss](https://avatars.discourse-cdn.com/v4/letter/f/67e7ee/32.png) [@famoss](https://discuss.elastic.co/u/famoss)\
**Post date:** [November 24, 2016, 10:25am UTC](https://discuss.elastic.co/t/do-full-gc-frequently/67084/1 "2016-11-24T10:25:05Z")

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Today,i find my es node do `full gc` frequently,but there are no other logs. I want to use `jmap` to dump the memory,but the dump file's size is `19GB`,`mat` can't analysis the file.

I use `_nodes/stats` to get the node info,but `fielddata` and `query cache` just use `2GB` size.

How can i to get the `full gc`'s reason?

Here is the `es` log.

```
[2016-11-24 17:06:48,451][INFO][monitor.jvm] [es140.213-2] [gc][old][6221773][2589] duration [18.7s], collections [2]/[18.9s], total [18.7s]/[17.3m], memory [22.9gb]->[11.4gb]/[24.8gb], all_pools {[young] [119.7mb]->[96.2mb]/[1.4gb]}{[survivor] [191.3mb]->[0b]/[191.3mb]}{[old] [22.6gb]->[11.3gb]/[23.1gb]}
[2016-11-24 17:09:18,663][WARN][monitor.jvm] [es140.213-2] [gc][old][6221898][2594] duration [21.2s], collections [2]/[21.3s], total [21.2s]/[17.6m], memory [23.9gb]->[11.7gb]/[24.8gb], all_pools {[young] [756.3mb]->[222.3mb]/[1.4gb]}{[survivor] [191.3mb]->[0b]/[191.3mb]}{[old] [23gb]->[11.5gb]/[23.1gb]}
[2016-11-24 17:11:11,928][WARN][monitor.jvm] [es140.213-2] [gc][old][6221990][2597] duration [18.7s], collections [1]/[19.5s], total [18.7s]/[17.9m], memory [22.8gb]->[11.4gb]/[24.8gb], all_pools {[young] [95.6mb]->[68.7mb]/[1.4gb]}{[survivor] [191.3mb]->[0b]/[191.3mb]}{[old] [22.5gb]->[11.3gb]/[23.1gb]}
[2016-11-24 17:13:35,252][WARN][monitor.jvm] [es140.213-2] [gc][old][6222112][2601] duration [17.5s], collections [1]/[17.7s], total [17.5s]/[18.2m], memory [23.5gb]->[11.2gb]/[24.8gb], all_pools {[young] [459.8mb]->[303.8mb]/[1.4gb]}{[survivor] [191.3mb]->[0b]/[191.3mb]}{[old] [22.9gb]->[10.9gb]/[23.1gb]}
[2016-11-24 17:15:35,798][WARN][monitor.jvm] [es140.213-2] [gc][old][6222213][2604] duration [17.2s], collections [1]/[17.6s], total [17.2s]/[18.5m], memory [23.7gb]->[11.1gb]/[24.8gb], all_pools {[young] [938.4mb]->[124.5mb]/[1.4gb]}{[survivor] [191.3mb]->[0b]/[191.3mb]}{[old] [22.6gb]->[11gb]/[23.1gb]}
```

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**Author:** ![jpountz](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/jpountz/32/45836_2.png) [@jpountz](https://discuss.elastic.co/u/jpountz)\
**Post date:** [November 25, 2016, 3:18pm UTC](https://discuss.elastic.co/t/do-full-gc-frequently/67084/2 "2016-11-25T15:18:22Z")

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> [@famoss](#):
>
> How can i to get the full gc's reason?

Unfortunately this is one of the hardest questions to answer. Maybe other tools than mat would support analyzing such a large dump?

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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:** [December 23, 2016, 3:18pm UTC](https://discuss.elastic.co/t/do-full-gc-frequently/67084/3 "2016-12-23T15:18:21Z")

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