org.apache.calcite.materialize

Interface LatticeStatisticProvider

All Known Implementing Classes:

CachingLatticeStatisticProvider, DelegatingLatticeStatisticProvider, ProfilerLatticeStatisticProvider, SqlLatticeStatisticProvider

public interface LatticeStatisticProvider

Estimates row counts for a lattice and its attributes.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	LatticeStatisticProvider.Factory Creates a LatticeStatisticProvider for a given Lattice.

Method Summary

Modifier and Type	Method and Description
double	cardinality(List<Lattice.Column> columns) Returns an estimate of the number of distinct values in a column or list of columns.

Method Detail

cardinality

double cardinality(List<Lattice.Column> columns)

Returns an estimate of the number of distinct values in a column or list of columns.