# What does this warning mean? Selector return prematurely

**URL:** <https://discuss.elastic.co/t/what-does-this-warning-mean-selector-return-prematurely/191171>\
**Category:** Elasticsearch\
**Created:** [July 18, 2019, 9:33am UTC](https://discuss.elastic.co/t/what-does-this-warning-mean-selector-return-prematurely/191171 "2019-07-18T09:33:23Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![yishain11](https://avatars.discourse-cdn.com/v4/letter/y/df705f/32.png) [@yishain11](https://discuss.elastic.co/u/yishain11)\
**Post date:** [July 18, 2019, 9:33am UTC](https://discuss.elastic.co/t/what-does-this-warning-mean-selector-return-prematurely/191171/1 "2019-07-18T09:33:23Z")

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I have nodejs server that is trying to push alot of docs into elasticsearch (single node).  
I get these messages in my elastic log:  
[2019-07-18T12:36:50,705][WARN][i.n.c.n.NioEventLoop] Selector.select() returned prematurely 512 times in a row; rebuilding Selector sun.nio.ch.EPollSelectorImpl@1399938e.  
[2019-07-18T12:36:50,705][WARN][i.n.c.n.NioEventLoop] Selector.select() returned prematurely 512 times in a row; rebuilding Selector sun.nio.ch.EPollSelectorImpl@1399938e.  
[2019-07-18T12:36:52,614][INFO][i.n.c.n.NioEventLoop] Migrated 32 channel(s) to the new Selector.  
[2019-07-18T12:36:52,614][INFO][i.n.c.n.NioEventLoop] Migrated 32 channel(s) to the new Selector.

What does that mean?  
I might add that not long after, while trying to push more docs, elastic crashes.

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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:** [August 15, 2019, 9:33am UTC](https://discuss.elastic.co/t/what-does-this-warning-mean-selector-return-prematurely/191171/2 "2019-08-15T09:33:31Z")

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