com.hazelcast.org.apache.calcite.rel.core.Intersect Maven / Gradle / Ivy
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package com.hazelcast.org.apache.calcite.rel.core;
import com.hazelcast.org.apache.calcite.plan.RelOptCluster;
import com.hazelcast.org.apache.calcite.plan.RelTraitSet;
import com.hazelcast.org.apache.calcite.rel.RelInput;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.hint.RelHint;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataQuery;
import com.hazelcast.org.apache.calcite.sql.SqlKind;
import java.util.Collections;
import java.util.List;
/**
* Relational expression that returns the intersection of the rows of its
* inputs.
*
* If "all" is true, performs then multiset intersection; otherwise,
* performs set set intersection (implying no duplicates in the results).
*/
public abstract class Intersect extends SetOp {
/**
* Creates an Intersect.
*/
public Intersect(
RelOptCluster cluster,
RelTraitSet traits,
List hints,
List inputs,
boolean all) {
super(cluster, traits, hints, inputs, SqlKind.INTERSECT, all);
}
/**
* Creates an Intersect.
*/
protected Intersect(
RelOptCluster cluster,
RelTraitSet traits,
List inputs,
boolean all) {
this(cluster, traits, Collections.emptyList(), inputs, all);
}
/**
* Creates an Intersect by parsing serialized output.
*/
protected Intersect(RelInput input) {
super(input);
}
@Override public double estimateRowCount(RelMetadataQuery mq) {
// REVIEW jvs 30-May-2005: I just pulled this out of a hat.
double dRows = Double.MAX_VALUE;
for (RelNode input : inputs) {
Double rowCount = mq.getRowCount(input);
if (rowCount == null) {
// Assume this input does not reduce row count
continue;
}
dRows = Math.min(dRows, rowCount);
}
dRows *= 0.25;
return dRows;
}
}