Path getBaseDir() {
      return baseDir;
    }
In case of isMajorCompaction() this is the base dir from the Compactor, i.e. either a base_x
or {@link #rootPath} if it's the 1st major compaction after non-acid2acid conversion
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcRawRecordMerger.java