org.apache.drill.metastore.statistics

Interface Histogram

All Known Implementing Classes:

NumericEquiDepthHistogram

public interface Histogram

A column specific histogram

Method Summary

Modifier and Type	Method and Description
Double	estimatedSelectivity(org.apache.calcite.rex.RexNode filter, long totalRowCount, long ndv) For a filter condition, estimate the selectivity (matching rows/total rows) for this histogram.

Method Detail

estimatedSelectivity

Double estimatedSelectivity(org.apache.calcite.rex.RexNode filter,
                            long totalRowCount,
                            long ndv)

For a filter condition, estimate the selectivity (matching rows/total rows) for this histogram.

Returns:

estimated selectivity or NULL if it could not be estimated for any reason