public List optimize()

in connectors/spark-tsfile/src/main/java/org/apache/iotdb/spark/tsfile/qp/optimizer/PhysicalOptimizer.java [53:134]
70 lines of code
14 McCabe index (conditional complexity)

  public List<TSQueryPlan> optimize(
      SingleQuery singleQuery, List<String> paths, TsFileSequenceReader in, Long start, Long end)
      throws IOException {

    Map<String, TSDataType> allMeasurementsInFile = in.getAllMeasurements();

    List<String> selectedSeries = new ArrayList<>();
    for (String path : paths) {
      if (!columnNames.contains(path) && !path.equals(SQLConstant.RESERVED_TIME)) {
        selectedSeries.add(path);
      }
    }
    FilterOperator timeFilter = null;
    FilterOperator valueFilter = null;

    if (singleQuery != null) {
      timeFilter = singleQuery.getTimeFilterOperator();
      valueFilter = singleQuery.getValueFilterOperator();
      if (valueFilter != null) {
        List<String> filterPaths = valueFilter.getAllPaths();
        // if filter paths doesn't in tsfile, don't read
        for (String filterPath : filterPaths) {
          if (!allMeasurementsInFile.containsKey(filterPath)) {
            return new ArrayList<>();
          }
        }
      }

      flag = true;
      Map<String, Set<String>> selectColumns = mergeColumns(singleQuery.getColumnFilterOperator());
      if (!flag) {
        // e.g. where column1 = 'd1' and column2 = 'd2', should not read
        return new ArrayList<>();
      }

      // if select deltaObject, then match with measurement
      List<String> actualDeltaObjects =
          in.getDeviceNameInRange(start, end).stream()
              .map(deviceID -> ((PlainDeviceID) deviceID).toStringID())
              .collect(Collectors.toList());
      if (!selectColumns.isEmpty()) {
        combination(
            actualDeltaObjects,
            selectColumns,
            selectColumns.keySet().toArray(),
            0,
            new String[selectColumns.size()]);
      } else {
        validDeltaObjects.addAll(actualDeltaObjects);
      }
    } else {
      validDeltaObjects.addAll(
          in.getDeviceNameInRange(start, end).stream()
              .map(deviceID -> ((PlainDeviceID) deviceID).toStringID())
              .collect(Collectors.toList()));
    }

    // query all measurements from TSFile
    if (selectedSeries.isEmpty()) {
      selectedSeries.addAll(allMeasurementsInFile.keySet());
    } else {
      // remove paths that doesn't exist in file
      selectedSeries.removeIf(path -> !allMeasurementsInFile.containsKey(path));
    }

    List<TSQueryPlan> tsFileQueries = new ArrayList<>();
    for (String deltaObject : validDeltaObjects) {
      List<String> newPaths = new ArrayList<>();
      for (String path : selectedSeries) {
        String newPath = deltaObject + SQLConstant.PATH_SEPARATOR + path;
        newPaths.add(newPath);
      }
      if (valueFilter == null) {
        tsFileQueries.add(new TSQueryPlan(newPaths, timeFilter, null));
      } else {
        FilterOperator newValueFilter = valueFilter.clone();
        newValueFilter.addHeadDeltaObjectPath(deltaObject);
        tsFileQueries.add(new TSQueryPlan(newPaths, timeFilter, newValueFilter));
      }
    }
    return tsFileQueries;
  }