private static long getBaseSize(AcidDirectory dir) throws IOException {
    long baseSize = 0;
    if (dir.getBase() != null) {
      baseSize = getDirSize(dir.getFs(), dir.getBase());
    } else {
      for (HadoopShims.HdfsFileStatusWithId origStat : dir.getOriginalFiles()) {
        baseSize += origStat.getFileStatus().getLen();
      }
    }
    return baseSize;
  }
Check for that special case when minor compaction is supported or not.
<ul>
  <li>The table is Insert-only OR</li>
  <li>Query based compaction is not enabled OR</li>
  <li>The table has only acid data in it.</li>
</ul>
@param tblProperties The properties of the table to check
@param dir The {@link AcidDirectory} instance pointing to the table's folder on the filesystem.
@return Returns true if minor compaction is supported based on the given parameters, false otherwise.
ql/src/java/org/apache/hadoop/hive/ql/txn/compactor/CompactorUtil.java