GraphiteWriterFactory does not actually write

The GraphiteWriter outputs to Graphite properly with a configuration like the following:

{
 "servers" : [
  {
   "port" : "PPPPP",
   "host" : "AAA.BBB.CCC",
   "queries" : [
    {
     "outputWriters" : [
      {
       "@class" : "com.googlecode.jmxtrans.model.output.GraphiteWriter",
       "rootPrefix" : "jmx",
       "port" : "2003",
       "host" : "127.0.0.1"
      }
     ],
     "obj" : "java.lang:type=Memory",
     "attr" : [ "HeapMemoryUsage", "NonHeapMemoryUsage" ],
     "resultAlias": "heap"
    }
   ]
  }
 ]
}

Changing the line

       "@class" : "com.googlecode.jmxtrans.model.output.GraphiteWriter",

to

       "@class" : "com.googlecode.jmxtrans.model.output.GraphiteWriterFactory",

let the output not working: no data reach the carbon-cache listener.

Excluding the deprecation of GraphiteWriter, there is nothing strange in the log, even at DEBUG level.

I found the behaviour in version 254 (I treid both .rpm and .jar flavour) and in version 255-SNAPSHOT20160511200238 (I tried rpm only).

[gehel]

Always flushing is probably not a very good default. It would mean that we send a very small packet with a single metric each time a metric is collected. It is more efficient to batch multiple metrics in a single TCP packet. If you collect enough metrics, never flushing (and letting the underlying TCP implementation handle the buffering) is the most efficient choice. If you collect less metrics, flushing periodically make sense. It is more expensive, but allow you to get results in a timely fashion.

A better default might be to flush every minute.

[marcoc610]

I am currently testing these parameters and the Graphite database is receiving data using GraphiteWriterFactory. I leave the parameters running for some time, then I will report again.