Package org.apache.calcite.materialize

Class SqlLatticeStatisticProvider

java.lang.Object

org.apache.calcite.materialize.SqlLatticeStatisticProvider

All Implemented Interfaces:

LatticeStatisticProvider

class SqlLatticeStatisticProvider
extends java.lang.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	Description
(package private) static LatticeStatisticProvider.Factory	CACHED_FACTORY
(package private) static LatticeStatisticProvider.Factory	FACTORY
private Lattice	lattice

Constructor Summary

Constructors

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

Method Summary

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

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(java.util.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)