# Logstash process hanging

**URL:** <https://discuss.elastic.co/t/logstash-process-hanging/32883>\
**Category:** Logstash\
**Created:** [October 23, 2015, 7:56pm UTC](https://discuss.elastic.co/t/logstash-process-hanging/32883 "2015-10-23T19:56:18Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mihir\_ray](https://avatars.discourse-cdn.com/v4/letter/m/e95f7d/32.png) [@mihir\_ray](https://discuss.elastic.co/u/mihir_ray)\
**Post date:** [October 23, 2015, 7:56pm UTC](https://discuss.elastic.co/t/logstash-process-hanging/32883/1 "2015-10-23T19:56:18Z")

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HI,

My input is kafka and output is a file.  
Sometimes i have seen the logstash process just hangs(doing nothing).

To debug this issue i enabled verbose logging and started the process.  
After few days of running, it hanged again with below error in the log:

{:timestamp=\>"2015-10-23T00:49:18.263000-0600", :message=\>"Exception in filterworker", "exception"=\>#\<RuntimeError: can't add a new key into hash during iteration\>, "backtrace"=\>["org/jruby/RubyHash.java:991:in `[]='", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/util/accessors.rb:119:in`find\_or\_create\_target'", "org/jruby/RubyArray.java:1613:in `each'", "org/jruby/RubyEnumerable.java:866:in`inject'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/util/accessors.rb:119:in `find_or_create_target'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/util/accessors.rb:98:in`lookup\_or\_create'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/util/accessors.rb:63:in `set'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/event.rb:146:in`[]='", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-filter-urldecode-1.0.0/lib/logstash/filters/urldecode.rb:36:in `filter'", "org/jruby/RubyHash.java:1341:in`each'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-filter-urldecode-1.0.0/lib/logstash/filters/urldecode.rb:36:in `filter'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/filters/base.rb:163:in`multi\_filter'", "org/jruby/RubyArray.java:1613:in `each'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/filters/base.rb:160:in`multi\_filter'", "(eval):155:in `filter_func'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/pipeline.rb:219:in`filterworker'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-core-1.5.4-java/lib/logstash/pipeline.rb:157:in `start\_filters'"], :level=\>:error}

Can someone please help understanding whats going on here?

Thanks

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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:** [July 6, 2017, 5:25am UTC](https://discuss.elastic.co/t/logstash-process-hanging/32883/2 "2017-07-06T05:25:35Z")

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