title: Streaming query not showing any progress in Spark
body: <p>I am getting status messages of the form from a Spark Structured Streaming Application:</p>
  
  <pre><code>  18/02/12 16:38:54 INFO StreamExecution: Streaming query made progress: {
    "id" : "a6c37f0b-51f4-47c5-a487-8bd269b80142",
    "runId" : "061e41b4-f488-4483-a290-403f1f7eff03",
    "name" : null,
    "timestamp" : "2018-02-12T11:08:54.323Z",
    "numInputRows" : 0,
    "processedRowsPerSecond" : 0.0,
    "durationMs" : {
      "getOffset" : 30,
      "triggerExecution" : 46
    },
    "eventTime" : {
      "watermark" : "1970-01-01T00:00:00.000Z"
    },
    "stateOperators" : [ ],
    "sources" : [ {
      "description" : "FileStreamSource[file:/home/chiralcarbon/IdeaProjects/spark_structured_streaming/args[0]]",
      "startOffset" : null,
      "endOffset" : null,
      "numInputRows" : 0,
      "processedRowsPerSecond" : 0.0
    } ],
    "sink" : {
      "description" : "org.apache.spark.sql.execution.streaming.ConsoleSink@bcc171"
    }
  }
  </code></pre>
  
  <p>All of the messages have numInputRows with value 0.</p>
  
  <p>The program streams data from a parquet file and outputs the same stream to the console.Following is the code:</p>
  
  <pre><code>def main(args: Array[String]): Unit = {
      val spark: SparkSession = SparkSession.builder.
        master("local")
        .appName("sparkSession")
        .getOrCreate()
  
      val schema = ..
      val in = spark.readStream
            .schema(schema)
            .parquet("args[0]")
  
      val query = in.writeStream
            .format("console")
            .outputMode("append")
            .start()
      query.awaitTermination()
  
    }
  
  }
  </code></pre>
  
  <p>What is the cause and how do I resolve this?</p>