@Override
  public void run(Map<String, LogicalInput> inputs,
                  Map<String, LogicalOutput> outputs) throws Exception {
    if(prewarmed) {
      /* container reuse */
      return;
    }
    for (LogicalInput input : inputs.values()) {
      input.start();
    }
    for (LogicalOutput output : outputs.values()) {
      output.start();
    }
    /* these are things that goes through singleton initialization on most queries */
    FileSystem fs = FileSystem.get(conf);
    Mac mac = Mac.getInstance("HmacSHA1");
    ReadaheadPool rpool = ReadaheadPool.getInstance();
    ShimLoader.getHadoopShims();

    URL hiveurl = new URL("jar:" + DagUtils.getInstance().getExecJarPathLocal(conf) + "!/");
    JarURLConnection hiveconn = (JarURLConnection)hiveurl.openConnection();
    JarFile hivejar = hiveconn.getJarFile();
    try {
      Enumeration<JarEntry> classes = hivejar.entries();
      while(classes.hasMoreElements()) {
        JarEntry je = classes.nextElement();
        if (je.getName().endsWith(".class")) {
          String klass = je.getName().replace(".class","").replaceAll("/","\\.");
          if(klass.indexOf("ql.exec") != -1 || klass.indexOf("ql.io") != -1) {
            /* several hive classes depend on the metastore APIs, which is not included
             * in hive-exec.jar. These are the relatively safe ones - operators & io classes.
             */
            if(klass.indexOf("vector") != -1 || klass.indexOf("Operator") != -1) {
              JavaUtils.loadClass(klass);
            }
          }
        }
      }
    } finally {
      hivejar.close();
    }
    prewarmed = true;
  }
A simple sleep processor implementation that sleeps for the configured
time in milliseconds.

@see Configuration for configuring the HivePreWarmProcessor
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/HivePreWarmProcessor.java