private void verifyDirAndResult(int expectedDeltas) throws Exception {
    verifyDirAndResult(expectedDeltas, false);
  }
Impala truncates insert-only tables by writing a base directory (like insert overwrite) containing a completely
empty file. Make sure that Hive reads these bases correctly.

@throws Exception
ql/src/test/org/apache/hadoop/hive/ql/TestTxnCommandsForMmTable.java