Logstash is periodically hanging (unresponsive). How to recognize and fix?

[PaulDonskikh (Paul)]

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Logstash Hangs (thread blocked)

Hi Everyone, We're running a Logstash pipeline with TCP input > JSON filter > ES output, and most of the time it goes great, except sometimes logstash will stop inserting data into ES without any log that we could find, and without crashing. It just hangs and stops processing data. The frequency of such 'freezes' is variable, roughly every one or two days. We send data to the TCP input (with SSL) from about 10 devices, at around 3 logs/second. The monitoring API shows that a worker thread som…