Package org.apache.calcite.statistic

Class CachingSqlStatisticProvider

java.lang.Object

org.apache.calcite.statistic.CachingSqlStatisticProvider

All Implemented Interfaces:

SqlStatisticProvider

public class CachingSqlStatisticProvider
extends Object
implements SqlStatisticProvider

Implementation of SqlStatisticProvider that reads and writes a cache.

Constructor Summary

Constructors

Constructor	Description
CachingSqlStatisticProvider(SqlStatisticProvider provider, com.google.common.cache.Cache<List,Object> cache)

Method Summary

Modifier and Type	Method	Description
boolean	isForeignKey(RelOptTable fromTable, List<Integer> fromColumns, RelOptTable toTable, List<Integer> toColumns)	Returns whether a join is a foreign key; that is, whether every row in the referencing table is matched by at least one row in the referenced table.
boolean	isKey(RelOptTable table, List<Integer> columns)	Returns whether a collection of columns is a unique (or primary) key.
double	tableCardinality(RelOptTable table)	Returns an estimate of the number of rows in table.

Methods inherited from class java.lang.Object

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

Constructor Details

CachingSqlStatisticProvider

public CachingSqlStatisticProvider(SqlStatisticProvider provider,
 com.google.common.cache.Cache<List,Object> cache)

Method Details

tableCardinality

public double tableCardinality(RelOptTable table)

Description copied from interface: SqlStatisticProvider

Returns an estimate of the number of rows in table.

Specified by:

tableCardinality in interface SqlStatisticProvider

isForeignKey

public boolean isForeignKey(RelOptTable fromTable,
 List<Integer> fromColumns,
 RelOptTable toTable,
 List<Integer> toColumns)

Description copied from interface: SqlStatisticProvider

Returns whether a join is a foreign key; that is, whether every row in the referencing table is matched by at least one row in the referenced table.

For example, isForeignKey(EMP, [DEPTNO], DEPT, [DEPTNO]) returns true.

To change "at least one" to "exactly one", you also need to call SqlStatisticProvider.isKey(org.apache.calcite.plan.RelOptTable, java.util.List<java.lang.Integer>).

Specified by:

isForeignKey in interface SqlStatisticProvider

isKey

public boolean isKey(RelOptTable table,
 List<Integer> columns)

Description copied from interface: SqlStatisticProvider

Returns whether a collection of columns is a unique (or primary) key.

For example, isKey(EMP, [DEPTNO] returns true; isKey(DEPT, [DEPTNO] returns false.

Specified by:

isKey in interface SqlStatisticProvider