private Directory callInternal() throws IOException {
      if (context.acidOperationalProperties == null
          || context.acidOperationalProperties.isInsertOnly()) {
        // For plain non-acid tables we just need to list all the files in the table / partition directory.
        // For MM tables HiveInputFormat#processPathsForMmRead already did filter out which
        // base / delta directories this query should read. The path in dir is either a base / delta / original
        // directory not the table / partition. So we just need to list the files, no need to do any acid related filtering.
        // In this context every file is considered original (since none of them is full ACID schema) this is not the same
        // as original files in the context of MM tables (see HiveConf.HIVE_MM_ALLOW_ORIGINALS)
        return listOriginalFiles();
      }
      //todo: shouldn't ignoreEmptyFiles be set based on ExecutionEngine?
      return getAcidState();
    }
For plain or acid tables this is the root of the partition (or table if not partitioned).
For MM table this is delta/ or base/ dir.  In MM case applying of the ValidTxnList that
{@link AcidUtils#getAcidState(FileSystem, Path, Configuration, ValidWriteIdList, Ref, boolean)}
normally does has already been done in
{@link HiveInputFormat#processPathsForMmRead(List, Configuration, ValidWriteIdList, List, List)}
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcInputFormat.java