Package org.apache.calcite.materialize

Class CachingLatticeStatisticProvider

java.lang.Object

org.apache.calcite.materialize.CachingLatticeStatisticProvider

All Implemented Interfaces:

LatticeStatisticProvider

class CachingLatticeStatisticProvider
extends java.lang.Object
implements LatticeStatisticProvider

Implementation of LatticeStatisticProvider that caches single-column statistics and computes multi-column statistics from these.

Nested Class Summary

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

LatticeStatisticProvider.Factory

Field Summary

Fields

Modifier and Type	Field	Description
private com.google.common.cache.LoadingCache<Lattice.Column,java.lang.Double>	cache
private Lattice	lattice

Constructor Summary

Constructors

Constructor	Description
CachingLatticeStatisticProvider(Lattice lattice, LatticeStatisticProvider provider)	Creates a CachingStatisticProvider.

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.

Methods inherited from class java.lang.Object

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

Field Detail

lattice

private final Lattice lattice

cache

private final com.google.common.cache.LoadingCache<Lattice.Column,java.lang.Double> cache

Constructor Detail

CachingLatticeStatisticProvider

CachingLatticeStatisticProvider(Lattice lattice,
                                LatticeStatisticProvider provider)

Creates a CachingStatisticProvider.

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