ExplainWork work = new ExplainWork(tmp, sem.getParseContext(), sem.getRootTasks(),
sem.getFetchTask(), astStringTree, sem, true, false, false, false, false);
ExplainTask task = new ExplainTask();
task.setWork(work);
task.initialize(conf, plan, null);
task.execute(null);
FSDataInputStream in = fs.open(tmp);
StringBuilder builder = new StringBuilder();
final int bufSz = 4096;
byte[] buf = new byte[bufSz];
long pos = 0L;