com.hazelcast.org.apache.calcite.rel.rules.UnionPullUpConstantsRule Maven / Gradle / Ivy
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* 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
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package com.hazelcast.org.apache.calcite.rel.rules;
import com.hazelcast.org.apache.calcite.plan.RelOptPredicateList;
import com.hazelcast.org.apache.calcite.plan.RelOptRuleCall;
import com.hazelcast.org.apache.calcite.plan.RelOptUtil;
import com.hazelcast.org.apache.calcite.plan.RelRule;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.rel.core.Union;
import com.hazelcast.org.apache.calcite.rel.metadata.RelMetadataQuery;
import com.hazelcast.org.apache.calcite.rel.type.RelDataTypeField;
import com.hazelcast.org.apache.calcite.rex.RexBuilder;
import com.hazelcast.org.apache.calcite.rex.RexInputRef;
import com.hazelcast.org.apache.calcite.rex.RexNode;
import com.hazelcast.org.apache.calcite.rex.RexUtil;
import com.hazelcast.org.apache.calcite.tools.RelBuilder;
import com.hazelcast.org.apache.calcite.tools.RelBuilderFactory;
import com.hazelcast.org.apache.calcite.util.ImmutableBitSet;
import com.hazelcast.org.apache.calcite.util.Pair;
import com.hazelcast.org.apache.calcite.util.mapping.Mappings;
import org.immutables.value.Value;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Planner rule that pulls up constants through a Union operator.
*
* @see CoreRules#UNION_PULL_UP_CONSTANTS
*/
@Value.Enclosing
public class UnionPullUpConstantsRule
extends RelRule
implements TransformationRule {
/** Creates a UnionPullUpConstantsRule. */
protected UnionPullUpConstantsRule(Config config) {
super(config);
}
@Deprecated // to be removed before 2.0
public UnionPullUpConstantsRule(Class extends Union> unionClass,
RelBuilderFactory relBuilderFactory) {
this(Config.DEFAULT.withRelBuilderFactory(relBuilderFactory)
.as(Config.class)
.withOperandFor(unionClass));
}
@Override public void onMatch(RelOptRuleCall call) {
final Union union = call.rel(0);
final RexBuilder rexBuilder = union.getCluster().getRexBuilder();
final RelMetadataQuery mq = call.getMetadataQuery();
final RelOptPredicateList predicates = mq.getPulledUpPredicates(union);
if (RelOptPredicateList.isEmpty(predicates)) {
return;
}
final Map constants = new HashMap<>();
for (Map.Entry e : predicates.constantMap.entrySet()) {
if (e.getKey() instanceof RexInputRef) {
constants.put(((RexInputRef) e.getKey()).getIndex(), e.getValue());
}
}
// None of the expressions are constant. Nothing to do.
if (constants.isEmpty()) {
return;
}
// Create expressions for Project operators before and after the Union
List fields = union.getRowType().getFieldList();
List topChildExprs = new ArrayList<>();
List topChildExprsFields = new ArrayList<>();
List refs = new ArrayList<>();
ImmutableBitSet.Builder refsIndexBuilder = ImmutableBitSet.builder();
for (RelDataTypeField field : fields) {
final RexNode constant = constants.get(field.getIndex());
if (constant != null) {
topChildExprs.add(constant);
topChildExprsFields.add(field.getName());
} else {
final RexNode expr = rexBuilder.makeInputRef(union, field.getIndex());
topChildExprs.add(expr);
topChildExprsFields.add(field.getName());
refs.add(expr);
refsIndexBuilder.set(field.getIndex());
}
}
ImmutableBitSet refsIndex = refsIndexBuilder.build();
// Update top Project positions
final Mappings.TargetMapping mapping =
RelOptUtil.permutation(refs, union.getInput(0).getRowType()).inverse();
topChildExprs = RexUtil.apply(mapping, topChildExprs);
// Create new Project-Union-Project sequences
final RelBuilder relBuilder = call.builder();
for (RelNode input : union.getInputs()) {
List> newChildExprs = new ArrayList<>();
for (int j : refsIndex) {
newChildExprs.add(
Pair.of(rexBuilder.makeInputRef(input, j),
input.getRowType().getFieldList().get(j).getName()));
}
if (newChildExprs.isEmpty()) {
// At least a single item in project is required.
newChildExprs.add(
Pair.of(topChildExprs.get(0), topChildExprsFields.get(0)));
}
// Add the input with project on top
relBuilder.push(input);
relBuilder.project(Pair.left(newChildExprs), Pair.right(newChildExprs));
}
relBuilder.union(union.all, union.getInputs().size());
// Create top Project fixing nullability of fields
relBuilder.project(topChildExprs, topChildExprsFields);
relBuilder.convert(union.getRowType(), false);
call.transformTo(relBuilder.build());
}
/** Rule configuration. */
@Value.Immutable
public interface Config extends RelRule.Config {
Config DEFAULT = ImmutableUnionPullUpConstantsRule.Config.of()
.withOperandFor(Union.class);
@Override default UnionPullUpConstantsRule toRule() {
return new UnionPullUpConstantsRule(this);
}
/** Defines an operand tree for the given classes. */
default Config withOperandFor(Class extends Union> unionClass) {
return withOperandSupplier(b ->
b.operand(unionClass)
// If field count is 1, then there's no room for
// optimization since we cannot create an empty Project
// operator. If we created a Project with one column,
// this rule would cycle.
.predicate(union -> union.getRowType().getFieldCount() > 1)
.anyInputs())
.as(Config.class);
}
}
}
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