# \[2.3.1\] Multiline - ConcurrencyError

**URL:** <https://discuss.elastic.co/t/2-3-1-multiline-concurrencyerror/50292>\
**Category:** Logstash\
**Created:** [May 18, 2016, 4:27am UTC](https://discuss.elastic.co/t/2-3-1-multiline-concurrencyerror/50292 "2016-05-18T04:27:52Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Romey-Rome](https://avatars.discourse-cdn.com/v4/letter/r/4da419/32.png) [@Romey-Rome](https://discuss.elastic.co/u/Romey-Rome)\
**Post date:** [May 18, 2016, 4:27am UTC](https://discuss.elastic.co/t/2-3-1-multiline-concurrencyerror/50292/1 "2016-05-18T04:27:52Z")

</div>

Get this error, then Logstash stops processing anything comping in on that port.

These are incoming Java stack traces.

It works for a while, then:

```
{:timestamp=>"2016-05-17T21:07:36.970000-0700", :message=>"Exception in inputworker", "exception"=>#<ConcurrencyError: Detected invalid array contents due to unsynchronized modifications with concurrent users>, "backtrace"=>["org/jruby/RubyArray.java:1147:in `<<'", "org/jruby/RubyArray.java:1168:in `push'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-codec-multiline-2.0.11/lib/logstash/codecs/multiline.rb:204:in `buffer'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-codec-multiline-2.0.11/lib/logstash/codecs/multiline.rb:262:in `do_previous'", "org/jruby/RubyMethod.java:124:in `call'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-codec-multiline-2.0.11/lib/logstash/codecs/multiline.rb:198:in `decode'", "org/jruby/RubyArray.java:1613:in `each'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-codec-multiline-2.0.11/lib/logstash/codecs/multiline.rb:191:in `decode'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-udp-2.0.5/lib/logstash/inputs/udp.rb:96:in `inputworker'", "/opt/logstash/vendor/bundle/jruby/1.9/gems/logstash-input-udp-2.0.5/lib/logstash/inputs/udp.rb:73:in `udp_listener'"], :level=>:error}

input {
  udp {
    port => 9119
    type => "error_log"
    codec => multiline {
       pattern => "^<%{NONNEGINT:prifacil}>(%{TIMESTAMP_ISO8601}|%{SYSLOGTIMESTAMP})"
       negate => true
       what => previous
    }
 }
}

filter {
   if [type] == "error_log" {
     grok {
      patterns_dir => "/etc/logstash/pattern.d"
      match => {"message" => "%{ERROR_LOG}"}
      }
  }
}

ERROR_LOG <%{NONNEGINT:prifacil}>(%{TIMESTAMP_ISO8601}|%{SYSLOGTIMESTAMP} %{DATA:src_host}) \(%{WORD:source_application}\)
```

---

<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, 4:57am UTC](https://discuss.elastic.co/t/2-3-1-multiline-concurrencyerror/50292/2 "2017-07-06T04:57:18Z")

</div>