io.trino.sql.planner.iterative.rule.PruneTopNColumns 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.Streams;
import io.trino.sql.planner.Symbol;
import io.trino.sql.planner.plan.PlanNode;
import io.trino.sql.planner.plan.TopNNode;
import java.util.Optional;
import java.util.Set;
import static com.google.common.collect.ImmutableSet.toImmutableSet;
import static io.trino.sql.planner.iterative.rule.Util.restrictChildOutputs;
import static io.trino.sql.planner.plan.Patterns.topN;
public class PruneTopNColumns
extends ProjectOffPushDownRule
{
public PruneTopNColumns()
{
super(topN());
}
@Override
protected Optional pushDownProjectOff(Context context, TopNNode topNNode, Set referencedOutputs)
{
Set prunedTopNInputs = Streams.concat(
referencedOutputs.stream(),
topNNode.getOrderingScheme().getOrderBy().stream())
.collect(toImmutableSet());
return restrictChildOutputs(context.getIdAllocator(), topNNode, prunedTopNInputs);
}
}