com.hazelcast.org.apache.calcite.rel.core.Correlate Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.org.apache.calcite.rel.core;
import com.hazelcast.org.apache.calcite.plan.RelOptCluster;
import com.hazelcast.org.apache.calcite.plan.RelOptCost;
import com.hazelcast.org.apache.calcite.plan.RelOptPlanner;
import com.hazelcast.org.apache.calcite.plan.RelOptUtil;
import com.hazelcast.org.apache.calcite.plan.RelTraitSet;
import com.hazelcast.org.apache.calcite.rel.BiRel;
import com.hazelcast.org.apache.calcite.rel.RelInput;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.RelWriter;
import com.hazelcast.org.apache.calcite.rel.hint.Hintable;
import com.hazelcast.org.apache.calcite.rel.hint.RelHint;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataQuery;
import com.hazelcast.org.apache.calcite.rel.type.RelDataType;
import com.hazelcast.org.apache.calcite.sql.validate.SqlValidatorUtil;
import com.hazelcast.org.apache.calcite.util.ImmutableBitSet;
import com.hazelcast.org.apache.calcite.util.Litmus;
import com.hazelcast.com.google.common.collect.ImmutableList;
import com.hazelcast.com.google.common.collect.ImmutableSet;
import com.hazelcast.org.checkerframework.checker.nullness.qual.Nullable;
import java.util.List;
import java.util.Set;
import static java.util.Objects.requireNonNull;
/**
* A relational operator that performs nested-loop joins.
*
* It behaves like a kind of {@link com.hazelcast.org.apache.calcite.rel.core.Join},
* but works by setting variables in its environment and restarting its
* right-hand input.
*
*
Correlate is not a join since: typical rules should not match Correlate.
*
*
A Correlate is used to represent a correlated query. One
* implementation strategy is to de-correlate the expression.
*
*
* Mapping of physical operations to logical ones
* Physical operation Logical operation NestedLoops Correlate(A, B, regular) NestedLoopsOuter Correlate(A, B, outer) NestedLoopsSemi Correlate(A, B, semi) NestedLoopsAnti Correlate(A, B, anti) HashJoin EquiJoin(A, B) HashJoinOuter EquiJoin(A, B, outer) HashJoinSemi SemiJoin(A, B, semi) HashJoinAnti SemiJoin(A, B, anti)
*
* @see CorrelationId
*/
public abstract class Correlate extends BiRel implements Hintable {
//~ Instance fields --------------------------------------------------------
protected final CorrelationId correlationId;
protected final ImmutableBitSet requiredColumns;
protected final JoinRelType joinType;
protected final ImmutableList hints;
//~ Constructors -----------------------------------------------------------
/**
* Creates a Correlate.
*
* @param cluster Cluster this relational expression belongs to
* @param left Left input relational expression
* @param right Right input relational expression
* @param correlationId Variable name for the row of left input
* @param requiredColumns Set of columns that are used by correlation
* @param joinType Join type
*/
@SuppressWarnings("method.invocation.invalid")
protected Correlate(
RelOptCluster cluster,
RelTraitSet traitSet,
List hints,
RelNode left,
RelNode right,
CorrelationId correlationId,
ImmutableBitSet requiredColumns,
JoinRelType joinType) {
super(cluster, traitSet, left, right);
assert !joinType.generatesNullsOnLeft() : "Correlate has invalid join type " + joinType;
this.joinType = requireNonNull(joinType, "joinType");
this.correlationId = requireNonNull(correlationId, "correlationId");
this.requiredColumns = requireNonNull(requiredColumns, "requiredColumns");
this.hints = ImmutableList.copyOf(hints);
assert isValid(Litmus.THROW, null);
}
@Deprecated // to be removed before 2.0
protected Correlate(
RelOptCluster cluster,
RelTraitSet traitSet,
RelNode left,
RelNode right,
CorrelationId correlationId,
ImmutableBitSet requiredColumns,
JoinRelType joinType) {
this(cluster, traitSet, ImmutableList.of(), left, right,
correlationId, requiredColumns, joinType);
}
/**
* Creates a Correlate by parsing serialized output.
*
* @param input Input representation
*/
protected Correlate(RelInput input) {
this(
input.getCluster(), input.getTraitSet(), input.getInputs().get(0),
input.getInputs().get(1),
new CorrelationId(
requireNonNull((Integer) input.get("correlation"), "correlation")),
input.getBitSet("requiredColumns"),
requireNonNull(input.getEnum("joinType", JoinRelType.class), "joinType"));
}
//~ Methods ----------------------------------------------------------------
@Override public boolean isValid(Litmus litmus, @Nullable Context context) {
ImmutableBitSet leftColumns = ImmutableBitSet.range(left.getRowType().getFieldCount());
return super.isValid(litmus, context)
&& litmus.check(leftColumns.contains(requiredColumns),
"Required columns {} not subset of left columns {}", requiredColumns, leftColumns)
&& RelOptUtil.notContainsCorrelation(left, correlationId, litmus);
}
@Override public Correlate copy(RelTraitSet traitSet, List inputs) {
assert inputs.size() == 2;
return copy(traitSet,
inputs.get(0),
inputs.get(1),
correlationId,
requiredColumns,
joinType);
}
public abstract Correlate copy(RelTraitSet traitSet,
RelNode left, RelNode right, CorrelationId correlationId,
ImmutableBitSet requiredColumns, JoinRelType joinType);
public JoinRelType getJoinType() {
return joinType;
}
@Override protected RelDataType deriveRowType() {
switch (joinType) {
case LEFT:
case INNER:
return SqlValidatorUtil.deriveJoinRowType(left.getRowType(),
right.getRowType(), joinType,
getCluster().getTypeFactory(), null,
ImmutableList.of());
case ANTI:
case SEMI:
return left.getRowType();
default:
throw new IllegalStateException("Unknown join type " + joinType);
}
}
@Override public RelWriter explainTerms(RelWriter pw) {
return super.explainTerms(pw)
.item("correlation", correlationId)
.item("joinType", joinType.lowerName)
.item("requiredColumns", requiredColumns);
}
/**
* Returns the correlating expressions.
*
* @return correlating expressions
*/
public CorrelationId getCorrelationId() {
return correlationId;
}
@Override public String getCorrelVariable() {
return correlationId.getName();
}
/**
* Returns the required columns in left relation required for the correlation
* in the right.
*
* @return columns in left relation required for the correlation in the right
*/
public ImmutableBitSet getRequiredColumns() {
return requiredColumns;
}
@Override public Set getVariablesSet() {
return ImmutableSet.of(correlationId);
}
@Override public double estimateRowCount(RelMetadataQuery mq) {
double leftRowCount = mq.getRowCount(left);
switch (joinType) {
case SEMI:
case ANTI:
return leftRowCount;
default:
return leftRowCount * mq.getRowCount(right);
}
}
@Override public @Nullable RelOptCost computeSelfCost(RelOptPlanner planner,
RelMetadataQuery mq) {
double rowCount = mq.getRowCount(this);
final double rightRowCount = right.estimateRowCount(mq);
final double leftRowCount = left.estimateRowCount(mq);
if (Double.isInfinite(leftRowCount) || Double.isInfinite(rightRowCount)) {
return planner.getCostFactory().makeInfiniteCost();
}
Double restartCount = mq.getRowCount(getLeft());
if (restartCount == null) {
return planner.getCostFactory().makeInfiniteCost();
}
// RelMetadataQuery.getCumulativeCost(getRight()); does not work for
// RelSubset, so we ask planner to cost-estimate right relation
RelOptCost rightCost = planner.getCost(getRight(), mq);
if (rightCost == null) {
return planner.getCostFactory().makeInfiniteCost();
}
RelOptCost rescanCost =
rightCost.multiplyBy(Math.max(1.0, restartCount - 1));
return planner.getCostFactory().makeCost(
rowCount /* generate results */ + leftRowCount /* scan left results */,
0, 0).plus(rescanCost);
}
@Override public ImmutableList getHints() {
return hints;
}
}