Logstash 6.2.4 stuck in infinite retry loop

[pankhuri]

Hi,

I am using logstash 6.2.4 with following yml settings -

pipeline.batch.size: 600
pipeline.workers: 1
dead_letter_queue.enable: true

The conf file used to run logstash application is -

input {
    file {
        path => "/home/administrator/Downloads/postgresql.log.2018-10-17-06"
        start_position => "beginning"
        }
}
filter {
  grok {
        match => { "message" => "%{DATESTAMP:timestamp} %{TZ}:%{IP:uip}\(%{NUMBER:num}\):%{WORD:dbuser}%{GREEDYDATA:msg}"}
}
        }
output {
   stdout { codec => rubydebug }
   elasticsearch {
   id => 'es-1'
   hosts => ["localhost:9200"]
   timeout => 60
   index => "dlq"
   version => "%{[@metadata][version]}"
   version_type => "external_gte"
 }
}

The input is a normal log file which is formatted using grok filter.
Here the version is always a string rather than a integer and thus elasticsearch throws error 400 Bad Request. (This is a test case for logstash and done intentionally)

On this error code - logstash should retry a finite number of times and then should push this request payload to dead_letter_queue file (as per the documentation - https://www.elastic.co/guide/en/logstash/current/dead-letter-queues.html), but it gets stuck in an infinite loop with mesaage -

[2018-10-23T12:11:42,475][ERROR][logstash.outputs.elasticsearch] Encountered a retryable error. Will Retry with exponential backoff {:code=>400, :url=>"localhost:9200/_bulk"}

Following are the contents of data/dead_letter_queue/main directory -

1.log (contains a single value "1")

Please assist if any configuration is missing leading to this situation.