Package org.apache.druid.segment.index

Class DictionaryRangeScanningBitmapIndex

java.lang.Object
org.apache.druid.segment.index.SimpleBitmapColumnIndex
org.apache.druid.segment.index.SimpleImmutableBitmapDelegatingIterableIndex
org.apache.druid.segment.index.DictionaryRangeScanningBitmapIndex
All Implemented Interfaces:
BitmapColumnIndex
public abstract class DictionaryRangeScanningBitmapIndex extends SimpleImmutableBitmapDelegatingIterableIndex
Common BitmapColumnIndex implementation for indexes which need to scan a range of values. Contains logic to skip computing indexes with computeBitmapResult(BitmapResultFactory, int, int, boolean) if rangeSize is larger than sizeScale multiplied by the number of selected rows. Numeric range indexes will typically want to set sizeScale to a double closer to 0.0 than to 1.0 because numeric comparisons are relatively cheap compared to bitmap operations. Most numerical implementations should use the value of ColumnConfig.skipValueRangeIndexScale().

Other implementations should adjust sizeScale as appropriate for the expense of the value matcher compared to the expense of the bitmap operations.

  • Constructor Details

    • DictionaryRangeScanningBitmapIndex

      public DictionaryRangeScanningBitmapIndex(double sizeScale, int rangeSize)

  • Method Details

    • estimatedComputeCost

      public int estimatedComputeCost()
      Description copied from interface: BitmapColumnIndex
      Returns an estimated cost for computing the bitmap result. Generally this is equivalent to number of bitmap union or intersection operations need to be performed. E.x. null value index bitmap has a cost of 0, non-null value index bitmap union with null bitmap has a cost of 1, range (size of 10) scanning index bitmap union with null bitmap has a cost of 10.

    • computeBitmapResult

      @Nullable public final <T> T computeBitmapResult(BitmapResultFactory<T> bitmapResultFactory, int applyRowCount, int totalRowCount, boolean includeUnknown)
      Description copied from interface: BitmapColumnIndex
      Compute a bitmap result wrapped with the BitmapResultFactory representing the rows matched by this index, or null if the index cannot (or should not) be computed.
      Parameters:
      bitmapResultFactory - helper to format the ImmutableBitmap in a form ready for consumption by callers
      applyRowCount - upper bound on number of rows this filter would be applied to, after removing rows short-circuited by prior bundle operations. For example, given "x AND y", if "x" is resolved using an index, then "y" will receive the number of rows that matched the filter "x". As another example, given "x OR y", if "x" is resolved using an index, then "y" will receive the number of rows that did *not* match the filter "x".
      totalRowCount - total number of rows to be scanned if no indexes are used
      includeUnknown - mapping for Druid native two state logic system into SQL three-state logic system. If set to true, bitmaps returned by this method should include true bits for any rows where the matching result is 'unknown', such as from the input being null valued.
      Returns:
      bitmap result representing rows matched by this index