org.apache.drill.exec.planner.cost

Class DrillRelMdDistinctRowCount

java.lang.Object

org.apache.calcite.rel.metadata.RelMdDistinctRowCount

org.apache.drill.exec.planner.cost.DrillRelMdDistinctRowCount

All Implemented Interfaces:

org.apache.calcite.rel.metadata.MetadataHandler<org.apache.calcite.rel.metadata.BuiltInMetadata.DistinctRowCount>

public class DrillRelMdDistinctRowCount
extends org.apache.calcite.rel.metadata.RelMdDistinctRowCount

Field Summary

Fields

Modifier and Type	Field and Description
static org.apache.calcite.rel.metadata.RelMetadataProvider	SOURCE

Constructor Summary

Constructors

Constructor and Description
DrillRelMdDistinctRowCount()

Method Summary

Modifier and Type	Method and Description
Double	getDistinctRowCount(org.apache.calcite.rel.core.Join rel, org.apache.calcite.rel.metadata.RelMetadataQuery mq, org.apache.calcite.util.ImmutableBitSet groupKey, org.apache.calcite.rex.RexNode predicate) We need to override this method since Calcite and Drill calculate joined row count in different ways.
Double	getDistinctRowCount(org.apache.calcite.rel.RelNode rel, org.apache.calcite.rel.metadata.RelMetadataQuery mq, org.apache.calcite.util.ImmutableBitSet groupKey, org.apache.calcite.rex.RexNode predicate)
Double	getDistinctRowCount(org.apache.calcite.plan.volcano.RelSubset rel, org.apache.calcite.rel.metadata.RelMetadataQuery mq, org.apache.calcite.util.ImmutableBitSet groupKey, org.apache.calcite.rex.RexNode predicate)

Methods inherited from class org.apache.calcite.rel.metadata.RelMdDistinctRowCount

getDef, getDistinctRowCount, getDistinctRowCount, getDistinctRowCount, getDistinctRowCount, getDistinctRowCount, getDistinctRowCount, getDistinctRowCount

Methods inherited from class java.lang.Object

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

Field Detail

SOURCE

public static final org.apache.calcite.rel.metadata.RelMetadataProvider SOURCE

Constructor Detail

DrillRelMdDistinctRowCount

public DrillRelMdDistinctRowCount()

Method Detail

getDistinctRowCount

public Double getDistinctRowCount(org.apache.calcite.rel.core.Join rel,
                                  org.apache.calcite.rel.metadata.RelMetadataQuery mq,
                                  org.apache.calcite.util.ImmutableBitSet groupKey,
                                  org.apache.calcite.rex.RexNode predicate)

We need to override this method since Calcite and Drill calculate joined row count in different ways. It helps avoid a case when at the first time was used Drill join row count but at the second time Calcite row count was used. It may happen when RelMdDistinctRowCount.getDistinctRowCount(Join, RelMetadataQuery, ImmutableBitSet, RexNode) method is used and after that used another getDistinctRowCount method for parent rel, which just uses row count of input rel node (our join rel). It causes cost increase of best rel node when RelSubset.propagateCostImprovements(org.apache.calcite.plan.volcano.VolcanoPlanner, org.apache.calcite.rel.metadata.RelMetadataQuery, org.apache.calcite.rel.RelNode, java.util.Set<org.apache.calcite.plan.volcano.RelSubset>) is called. This is a part of the fix for CALCITE-2018.

Overrides:

getDistinctRowCount in class org.apache.calcite.rel.metadata.RelMdDistinctRowCount

getDistinctRowCount

public Double getDistinctRowCount(org.apache.calcite.rel.RelNode rel,
                                  org.apache.calcite.rel.metadata.RelMetadataQuery mq,
                                  org.apache.calcite.util.ImmutableBitSet groupKey,
                                  org.apache.calcite.rex.RexNode predicate)

Overrides:

getDistinctRowCount in class org.apache.calcite.rel.metadata.RelMdDistinctRowCount

getDistinctRowCount

public Double getDistinctRowCount(org.apache.calcite.plan.volcano.RelSubset rel,
                                  org.apache.calcite.rel.metadata.RelMetadataQuery mq,
                                  org.apache.calcite.util.ImmutableBitSet groupKey,
                                  org.apache.calcite.rex.RexNode predicate)

Overrides:

getDistinctRowCount in class org.apache.calcite.rel.metadata.RelMdDistinctRowCount