org.apache.calcite.materialize

Class SqlLatticeStatisticProvider

java.lang.Object

org.apache.calcite.materialize.SqlLatticeStatisticProvider

All Implemented Interfaces:

LatticeStatisticProvider

class SqlLatticeStatisticProvider
extends Object
implements LatticeStatisticProvider

Implementation of LatticeStatisticProvider that gets statistics by executing "SELECT COUNT(DISTINCT ...) ..." SQL queries.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.materialize.LatticeStatisticProvider

LatticeStatisticProvider.Factory

Field Summary

Fields

Modifier and Type	Field and Description
(package private) static LatticeStatisticProvider.Factory	CACHED_FACTORY
(package private) static LatticeStatisticProvider.Factory	FACTORY
private Lattice	lattice

Constructor Summary

Constructors

Modifier	Constructor and Description
private	SqlLatticeStatisticProvider(Lattice lattice) Creates a SqlLatticeStatisticProvider.

Method Summary

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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FACTORY

static final LatticeStatisticProvider.Factory FACTORY

CACHED_FACTORY

static final LatticeStatisticProvider.Factory CACHED_FACTORY

lattice

private final Lattice lattice

Constructor Detail

SqlLatticeStatisticProvider

private SqlLatticeStatisticProvider(Lattice lattice)

Creates a SqlLatticeStatisticProvider.

Method Detail

cardinality

public double cardinality(List<Lattice.Column> columns)

Description copied from interface: LatticeStatisticProvider

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

Specified by:

cardinality in interface LatticeStatisticProvider

cardinality

private double cardinality(Lattice lattice,
                           Lattice.Column column)