Cannot flush pipeline logstash hangs

Elastic Stack Logstash
1

I am running logstash 2.3.1 on solaris 10 with java version "1.7.0_55".
$ bin/logstash -f config.txt -w 16 --log ./logs/logstash.log -vv
It loads the config file fine, reads in a lot of data but then tries to put a flush onto the pipeline. At this point its stuck and constantly repeats the following in the log file:
...
{:timestamp=>"2016-04-26T15:46:51.987000-0700", :message=>"Pushing flush onto pipeline", :level=>:debug, :file=>"logstash/pipeline.rb", :line=>"458", :method=>"flush"}
...

How can I fix this?

Is there any way to tell how much (items or memory) of the queue is full and/or if it is stuck because its blocked?

2

Maybe I'm missing something here, but is the same queue being used to process data as well as issue operation commands like 'flush'? If so, this seems like a very bad design since a blocking queue can stop the functionality if stuffed with data messages effectively creating a denial of service, no?