class CachingLatticeStatisticProvider extends java.lang.Object implements LatticeStatisticProvider
LatticeStatisticProvider
that caches single-column
statistics and computes multi-column statistics from these.LatticeStatisticProvider.Factory
Modifier and Type | Field and Description |
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private com.google.common.cache.LoadingCache<Lattice.Column,java.lang.Double> |
cache |
private Lattice |
lattice |
Constructor and Description |
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CachingLatticeStatisticProvider(Lattice lattice,
LatticeStatisticProvider provider)
Creates a CachingStatisticProvider.
|
Modifier and Type | Method and Description |
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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 final Lattice lattice
private final com.google.common.cache.LoadingCache<Lattice.Column,java.lang.Double> cache
CachingLatticeStatisticProvider(Lattice lattice, LatticeStatisticProvider provider)
public double cardinality(java.util.List<Lattice.Column> columns)
LatticeStatisticProvider
cardinality
in interface LatticeStatisticProvider
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