Package org.apache.druid.segment

Class SimpleTopNOptimizationInspector

java.lang.Object
org.apache.druid.segment.SimpleTopNOptimizationInspector
All Implemented Interfaces:
TopNOptimizationInspector
public class SimpleTopNOptimizationInspector extends Object implements TopNOptimizationInspector

  • Constructor Details

    • SimpleTopNOptimizationInspector

      public SimpleTopNOptimizationInspector(boolean allDictionaryIdsPresent)

  • Method Details

    • areAllDictionaryIdsPresent

      public boolean areAllDictionaryIdsPresent()
      Description copied from interface: TopNOptimizationInspector
      Returns true if all values in the dictionary are present in rows. Returns false such as this segment can filter some rows out even if the query does not specify a filter, making the actual column cardinality be lower than what DimensionDictionarySelector.getValueCardinality() returns. Dimension selectors for such cursors can return non-contiguous dictionary IDs because the dictionary IDs in filtered rows will not be returned. Note that the number of rows accessible via cursors created on these segments will not necessarily decrease because of the built-in filters. For inner joins, for example, the number of joined rows can be larger than the number of rows in the base segment even though this method returns false.
      Specified by:
      areAllDictionaryIdsPresent in interface TopNOptimizationInspector