com.hazelcast.org.apache.calcite.rel.rules.AggregateRemoveRule 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 com.hazelcast.com.liance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.com.hazelcast.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.rules;
import com.hazelcast.org.apache.calcite.plan.RelOptRule;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleCall;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.core.Aggregate;
import com.hazelcast.org.apache.calcite.rel.core.AggregateCall;
import com.hazelcast.org.apache.calcite.rel.core.RelFactories;
import com.hazelcast.org.apache.calcite.rel.logical.LogicalAggregate;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataQuery;
import com.hazelcast.org.apache.calcite.rex.RexBuilder;
import com.hazelcast.org.apache.calcite.rex.RexNode;
import com.hazelcast.org.apache.calcite.runtime.SqlFunctions;
import com.hazelcast.org.apache.calcite.sql.SqlAggFunction;
import com.hazelcast.org.apache.calcite.sql.SqlKind;
import com.hazelcast.org.apache.calcite.sql.SqlSplittableAggFunction;
import com.hazelcast.org.apache.calcite.tools.RelBuilder;
import com.hazelcast.org.apache.calcite.tools.RelBuilderFactory;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
/**
* Planner rule that removes
* a {@link com.hazelcast.org.apache.calcite.rel.core.Aggregate}
* if it com.hazelcast.com.utes no aggregate functions
* (that is, it is implementing {@code SELECT DISTINCT}),
* or all the aggregate functions are splittable,
* and the underlying relational expression is already distinct.
*/
public class AggregateRemoveRule extends RelOptRule implements SubstitutionRule {
public static final AggregateRemoveRule INSTANCE =
new AggregateRemoveRule(LogicalAggregate.class,
RelFactories.LOGICAL_BUILDER);
//~ Constructors -----------------------------------------------------------
@Deprecated // to be removed before 2.0
public AggregateRemoveRule(Class aggregateClass) {
this(aggregateClass, RelFactories.LOGICAL_BUILDER);
}
/**
* Creates an AggregateRemoveRule.
*/
public AggregateRemoveRule(Class aggregateClass,
RelBuilderFactory relBuilderFactory) {
super(
operandJ(aggregateClass, null, agg -> isAggregateSupported(agg),
any()), relBuilderFactory, null);
}
private static boolean isAggregateSupported(Aggregate aggregate) {
if (aggregate.getGroupType() != Aggregate.Group.SIMPLE
|| aggregate.getGroupCount() == 0) {
return false;
}
// If any aggregate functions do not support splitting, bail out.
for (AggregateCall aggregateCall : aggregate.getAggCallList()) {
if (aggregateCall.filterArg >= 0
|| aggregateCall.getAggregation()
.unwrap(SqlSplittableAggFunction.class) == null) {
return false;
}
}
return true;
}
//~ Methods ----------------------------------------------------------------
public void onMatch(RelOptRuleCall call) {
final Aggregate aggregate = call.rel(0);
final RelNode input = aggregate.getInput();
final RelMetadataQuery mq = call.getMetadataQuery();
if (!SqlFunctions.isTrue(mq.areColumnsUnique(input, aggregate.getGroupSet()))) {
return;
}
final RelBuilder relBuilder = call.builder();
final RexBuilder rexBuilder = relBuilder.getRexBuilder();
final List projects = new ArrayList<>();
for (AggregateCall aggCall : aggregate.getAggCallList()) {
final SqlAggFunction aggregation = aggCall.getAggregation();
if (aggregation.getKind() == SqlKind.SUM0) {
// Bail out for SUM0 to avoid potential infinite rule matching,
// because it may be generated by transforming SUM aggregate
// function to SUM0 and COUNT.
return;
}
final SqlSplittableAggFunction splitter =
Objects.requireNonNull(
aggregation.unwrap(SqlSplittableAggFunction.class));
final RexNode singleton = splitter.singleton(
rexBuilder, input.getRowType(), aggCall);
projects.add(singleton);
}
final RelNode newInput = convert(input, aggregate.getTraitSet().simplify());
relBuilder.push(newInput);
if (!projects.isEmpty()) {
projects.addAll(0, relBuilder.fields(aggregate.getGroupSet()));
relBuilder.project(projects);
} else if (newInput.getRowType().getFieldCount()
> aggregate.getRowType().getFieldCount()) {
// If aggregate was projecting a subset of columns, and there were no
// aggregate functions, add a project for the same effect.
relBuilder.project(relBuilder.fields(aggregate.getGroupSet()));
}
call.getPlanner().prune(aggregate);
call.transformTo(relBuilder.build());
}
}