io.trino.sql.planner.iterative.rule.PrunePatternRecognitionSourceColumns Maven / Gradle / Ivy
/*
* Licensed 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 io.trino.sql.planner.iterative.rule;
import com.google.common.collect.ImmutableSet;
import io.trino.matching.Captures;
import io.trino.matching.Pattern;
import io.trino.sql.planner.Symbol;
import io.trino.sql.planner.iterative.Rule;
import io.trino.sql.planner.plan.PatternRecognitionNode;
import io.trino.sql.planner.rowpattern.LogicalIndexExtractor;
import static com.google.common.base.Preconditions.checkState;
import static io.trino.sql.planner.iterative.rule.Util.restrictChildOutputs;
import static io.trino.sql.planner.plan.Patterns.PatternRecognition.rowsPerMatch;
import static io.trino.sql.planner.plan.Patterns.patternRecognition;
import static io.trino.sql.tree.PatternRecognitionRelation.RowsPerMatch.ONE;
/**
* This rule restricts the inputs to PatternRecognitionNode
* based on which symbols are used by the inner structures
* of the PatternRecognitionNode. As opposite to
* PrunePattenRecognitionColumns rule, this rule is not
* aware of which output symbols of the PatternRecognitionNode
* are used by the upstream plan. Consequentially, it can only
* prune the inputs which are not exposed to the output.
* Such possibility applies only to PatternRecognitionNode
* with the option `ONE ROW PER MATCH`, where only the partitioning
* symbols are passed to output.
*
* This rule is complementary to PrunePatternRecognitionColumns.
* It can prune PatternRecognitionNode's inputs in cases when
* there is no narrowing projection on top of the node.
*/
public class PrunePatternRecognitionSourceColumns
implements Rule
{
private static final Pattern PATTERN = patternRecognition()
.with(rowsPerMatch().matching(rowsPerMatch -> rowsPerMatch == ONE));
@Override
public Pattern getPattern()
{
return PATTERN;
}
@Override
public Result apply(PatternRecognitionNode node, Captures captures, Context context)
{
checkState(node.getWindowFunctions().isEmpty(), "invalid node: window functions present with ONE ROW PER MATCH");
checkState(node.getCommonBaseFrame().isEmpty(), "invalid node: common base frame present with ONE ROW PER MATCH");
ImmutableSet.Builder referencedInputs = ImmutableSet.builder();
referencedInputs.addAll(node.getPartitionBy());
node.getOrderingScheme().ifPresent(orderingScheme -> referencedInputs.addAll(orderingScheme.getOrderBy()));
node.getHashSymbol().ifPresent(referencedInputs::add);
node.getMeasures().values().stream()
.map(PatternRecognitionNode.Measure::getExpressionAndValuePointers)
.map(LogicalIndexExtractor.ExpressionAndValuePointers::getInputSymbols)
.forEach(referencedInputs::addAll);
node.getVariableDefinitions().values().stream()
.map(LogicalIndexExtractor.ExpressionAndValuePointers::getInputSymbols)
.forEach(referencedInputs::addAll);
return restrictChildOutputs(context.getIdAllocator(), node, referencedInputs.build())
.map(Result::ofPlanNode)
.orElse(Result.empty());
}
}