Package org.apache.druid.query.rowsandcols.semantic

Interface GroupPartitioner

All Known Implementing Classes:
DefaultGroupPartitioner
public interface GroupPartitioner
A semantic interface used to partition a data set based on a given set of dimensions.

  • Method Summary

    Modifier and Type
    Method
    Description
    int[]
    computeGroupings(List<String> columns)
    Computes the groupings of the underlying rows based on the columns passed in for grouping.

  • Method Details

    • computeGroupings

      int[] computeGroupings(List<String> columns)
      Computes the groupings of the underlying rows based on the columns passed in for grouping. The grouping is returned as an int[], the length of the array will be equal to the number of rows of data and the values of the elements of the array will be the same when the rows are part of the same group and different when the rows are part of different groups. This is contrasted with the SortedGroupPartitioner in that, the groupings returned are not necessarily contiguous. There is also no sort-order implied by the `int` values assigned to each grouping.
      Parameters:
      columns - the columns to group with
      Returns:
      the groupings, rows with the same int value are in the same group. There is no sort-order implied by the int values.