@Test
  public final void testComparatorsFromJoinQual() {
    Schema outerSchema = new Schema();
    outerSchema.addColumn("employee.id1", CatalogUtil.newSimpleDataType(Type.INT4));
    outerSchema.addColumn("employee.id2", CatalogUtil.newSimpleDataType(Type.INT4));
    Schema innerSchema = new Schema();
    innerSchema.addColumn("people.fid1", CatalogUtil.newSimpleDataType(Type.INT4));
    innerSchema.addColumn("people.fid2", CatalogUtil.newSimpleDataType(Type.INT4));

    FieldEval f1 = new FieldEval("employee.id1", CatalogUtil.newSimpleDataType(Type.INT4));
    FieldEval f2 = new FieldEval("people.fid1", CatalogUtil.newSimpleDataType(Type.INT4));
    FieldEval f3 = new FieldEval("employee.id2", CatalogUtil.newSimpleDataType(Type.INT4));
    FieldEval f4 = new FieldEval("people.fid2", CatalogUtil.newSimpleDataType(Type.INT4));

    EvalNode joinQual = new BinaryEval(EvalType.EQUAL, f1, f2);
    TupleComparator[] comparators =
        PlannerUtil.getComparatorsFromJoinQual(joinQual, outerSchema, innerSchema);

    Tuple t1 = new VTuple(2);
    t1.put(0, DatumFactory.createInt4(1));
    t1.put(1, DatumFactory.createInt4(2));

    Tuple t2 = new VTuple(2);
    t2.put(0, DatumFactory.createInt4(2));
    t2.put(1, DatumFactory.createInt4(3));

    TupleComparator outerComparator = comparators[0];
    assertTrue(outerComparator.compare(t1, t2) < 0);
    assertTrue(outerComparator.compare(t2, t1) > 0);

    TupleComparator innerComparator = comparators[1];
    assertTrue(innerComparator.compare(t1, t2) < 0);
    assertTrue(innerComparator.compare(t2, t1) > 0);

    // tests for composited join key
    EvalNode joinQual2 = new BinaryEval(EvalType.EQUAL, f3, f4);
    EvalNode compositedJoinQual = new BinaryEval(EvalType.AND, joinQual, joinQual2);
    comparators =
        PlannerUtil.getComparatorsFromJoinQual(compositedJoinQual, outerSchema, innerSchema);

    outerComparator = comparators[0];
    assertTrue(outerComparator.compare(t1, t2) < 0);
    assertTrue(outerComparator.compare(t2, t1) > 0);

    innerComparator = comparators[1];
    assertTrue(innerComparator.compare(t1, t2) < 0);
    assertTrue(innerComparator.compare(t2, t1) > 0);
  }
  public FileChunk getFileCunks(Path outDir, String startKey, String endKey, boolean last)
      throws IOException {
    BSTIndex index = new BSTIndex(new TajoConf());
    BSTIndex.BSTIndexReader idxReader = index.getIndexReader(new Path(outDir, "index"));
    idxReader.open();
    Schema keySchema = idxReader.getKeySchema();
    TupleComparator comparator = idxReader.getComparator();

    LOG.info(
        "BSTIndex is loaded from disk (" + idxReader.getFirstKey() + ", " + idxReader.getLastKey());

    File data = new File(URI.create(outDir.toUri() + "/output"));
    byte[] startBytes = Base64.decodeBase64(startKey);
    byte[] endBytes = Base64.decodeBase64(endKey);

    Tuple start;
    Tuple end;
    try {
      start = RowStoreUtil.RowStoreDecoder.toTuple(keySchema, startBytes);
    } catch (Throwable t) {
      throw new IllegalArgumentException(
          "StartKey: " + startKey + ", decoded byte size: " + startBytes.length, t);
    }

    try {
      end = RowStoreUtil.RowStoreDecoder.toTuple(keySchema, endBytes);
    } catch (Throwable t) {
      throw new IllegalArgumentException(
          "EndKey: " + endKey + ", decoded byte size: " + endBytes.length, t);
    }

    if (!comparator.isAscendingFirstKey()) {
      Tuple tmpKey = start;
      start = end;
      end = tmpKey;
    }

    LOG.info(
        "GET Request for "
            + data.getAbsolutePath()
            + " (start="
            + start
            + ", end="
            + end
            + (last ? ", last=true" : "")
            + ")");

    if (idxReader.getFirstKey() == null && idxReader.getLastKey() == null) { // if # of rows is zero
      LOG.info("There is no contents");
      return null;
    }

    if (comparator.compare(end, idxReader.getFirstKey()) < 0
        || comparator.compare(idxReader.getLastKey(), start) < 0) {
      LOG.info(
          "Out of Scope (indexed data ["
              + idxReader.getFirstKey()
              + ", "
              + idxReader.getLastKey()
              + "], but request start:"
              + start
              + ", end: "
              + end);
      return null;
    }

    long startOffset;
    long endOffset;
    try {
      startOffset = idxReader.find(start);
    } catch (IOException ioe) {
      LOG.error(
          "State Dump (the requested range: "
              + new TupleRange(keySchema, start, end)
              + ", idx min: "
              + idxReader.getFirstKey()
              + ", idx max: "
              + idxReader.getLastKey());
      throw ioe;
    }
    try {
      endOffset = idxReader.find(end);
      if (endOffset == -1) {
        endOffset = idxReader.find(end, true);
      }
    } catch (IOException ioe) {
      LOG.error(
          "State Dump (the requested range: "
              + new TupleRange(keySchema, start, end)
              + ", idx min: "
              + idxReader.getFirstKey()
              + ", idx max: "
              + idxReader.getLastKey());
      throw ioe;
    }

    // if startOffset == -1 then case 2-1 or case 3
    if (startOffset == -1) { // this is a hack
      // if case 2-1 or case 3
      try {
        startOffset = idxReader.find(start, true);
      } catch (IOException ioe) {
        LOG.error(
            "State Dump (the requested range: "
                + new TupleRange(keySchema, start, end)
                + ", idx min: "
                + idxReader.getFirstKey()
                + ", idx max: "
                + idxReader.getLastKey());
        throw ioe;
      }
    }

    if (startOffset == -1) {
      throw new IllegalStateException(
          "startOffset "
              + startOffset
              + " is negative \n"
              + "State Dump (the requested range: "
              + new TupleRange(keySchema, start, end)
              + ", idx min: "
              + idxReader.getFirstKey()
              + ", idx max: "
              + idxReader.getLastKey());
    }

    // if greater than indexed values
    if (last || (endOffset == -1 && comparator.compare(idxReader.getLastKey(), end) < 0)) {
      endOffset = data.length();
    }

    FileChunk chunk = new FileChunk(data, startOffset, endOffset - startOffset);
    LOG.info("Retrieve File Chunk: " + chunk);
    return chunk;
  }
  @Test
  public final void testNext() throws IOException, PlanningException {
    FileFragment[] frags =
        StorageManager.splitNG(
            conf, "employee", employee.getMeta(), employee.getPath(), Integer.MAX_VALUE);
    Path workDir = new Path(testDir, TestExternalSortExec.class.getName());
    TaskAttemptContext ctx =
        new TaskAttemptContext(
            conf,
            LocalTajoTestingUtility.newQueryUnitAttemptId(),
            new FileFragment[] {frags[0]},
            workDir);
    ctx.setEnforcer(new Enforcer());
    Expr expr = analyzer.parse(QUERIES[0]);
    LogicalPlan plan = planner.createPlan(expr);
    LogicalNode rootNode = plan.getRootBlock().getRoot();

    PhysicalPlanner phyPlanner = new PhysicalPlannerImpl(conf, sm);
    PhysicalExec exec = phyPlanner.createPlan(ctx, rootNode);

    ProjectionExec proj = (ProjectionExec) exec;

    // TODO - should be planed with user's optimization hint
    if (!(proj.getChild() instanceof ExternalSortExec)) {
      UnaryPhysicalExec sortExec = proj.getChild();
      SeqScanExec scan = sortExec.getChild();

      ExternalSortExec extSort =
          new ExternalSortExec(ctx, sm, ((MemSortExec) sortExec).getPlan(), scan);
      proj.setChild(extSort);
    }

    Tuple tuple;
    Tuple preVal = null;
    Tuple curVal;
    int cnt = 0;
    exec.init();
    long start = System.currentTimeMillis();
    TupleComparator comparator =
        new TupleComparator(
            proj.getSchema(),
            new SortSpec[] {
              new SortSpec(new Column("managerId", Type.INT4)),
              new SortSpec(new Column("empId", Type.INT4))
            });

    while ((tuple = exec.next()) != null) {
      curVal = tuple;
      if (preVal != null) {
        assertTrue(
            "prev: " + preVal + ", but cur: " + curVal, comparator.compare(preVal, curVal) <= 0);
      }
      preVal = curVal;
      cnt++;
    }
    long end = System.currentTimeMillis();
    assertEquals(numTuple, cnt);

    // for rescan test
    preVal = null;
    exec.rescan();
    cnt = 0;
    while ((tuple = exec.next()) != null) {
      curVal = tuple;
      if (preVal != null) {
        assertTrue(
            "prev: " + preVal + ", but cur: " + curVal, comparator.compare(preVal, curVal) <= 0);
      }
      preVal = curVal;
      cnt++;
    }
    assertEquals(numTuple, cnt);
    exec.close();
    System.out.println("Sort Time: " + (end - start) + " msc");
  }