title: Change output filename prefix for DataFrame.write()
body: <p>Output files generated via the Spark SQL DataFrame.write() method begin with the "part" basename prefix. e.g.</p>
  
  <pre><code>DataFrame sample_07 = hiveContext.table("sample_07");
  sample_07.write().parquet("sample_07_parquet");
  </code></pre>
  
  <p>Results in:</p>
  
  <pre><code>hdfs dfs -ls sample_07_parquet/                                                                                                                                                             
  Found 4 items
  -rw-r--r--   1 rob rob          0 2016-03-19 16:40 sample_07_parquet/_SUCCESS
  -rw-r--r--   1 rob rob        491 2016-03-19 16:40 sample_07_parquet/_common_metadata
  -rw-r--r--   1 rob rob       1025 2016-03-19 16:40 sample_07_parquet/_metadata
  -rw-r--r--   1 rob rob      17194 2016-03-19 16:40 sample_07_parquet/part-r-00000-cefb2ac6-9f44-4ce4-93d9-8e7de3f2cb92.gz.parquet
  </code></pre>
  
  <p>I would like to change the output filename prefix used when creating a file using Spark SQL DataFrame.write(). I tried setting the "mapreduce.output.basename" property on the hadoop configuration for the Spark context. e.g.</p>
  
  <pre><code>public class MyJavaSparkSQL {
  
    public static void main(String[] args) throws Exception {
      SparkConf sparkConf = new SparkConf().setAppName("MyJavaSparkSQL");
      JavaSparkContext ctx = new JavaSparkContext(sparkConf);
      ctx.hadoopConfiguration().set("mapreduce.output.basename", "myprefix");
      HiveContext hiveContext = new org.apache.spark.sql.hive.HiveContext(ctx.sc());
      DataFrame sample_07 = hiveContext.table("sample_07");
      sample_07.write().parquet("sample_07_parquet");
      ctx.stop();
    }
  </code></pre>
  
  <p>That did not change the output filename prefix for the generated files.</p>
  
  <p>Is there a way to override the output filename prefix when using the DataFrame.write() method?</p>