io.trino.sql.planner.iterative.rule.CreatePartialTopN 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 io.trino.Session;
import io.trino.matching.Captures;
import io.trino.matching.Pattern;
import io.trino.sql.planner.iterative.Rule;
import io.trino.sql.planner.plan.TopNNode;
import static io.trino.SystemSessionProperties.isUsePartialTopN;
import static io.trino.sql.planner.plan.Patterns.TopN.step;
import static io.trino.sql.planner.plan.Patterns.topN;
import static io.trino.sql.planner.plan.TopNNode.Step.FINAL;
import static io.trino.sql.planner.plan.TopNNode.Step.PARTIAL;
import static io.trino.sql.planner.plan.TopNNode.Step.SINGLE;
public class CreatePartialTopN
implements Rule
{
private static final Pattern PATTERN = topN()
.with(step().equalTo(SINGLE));
@Override
public boolean isEnabled(Session session)
{
return isUsePartialTopN(session);
}
@Override
public Pattern getPattern()
{
return PATTERN;
}
@Override
public Result apply(TopNNode single, Captures captures, Context context)
{
TopNNode partial = new TopNNode(
context.getIdAllocator().getNextId(),
single.getSource(),
single.getCount(),
single.getOrderingScheme(),
PARTIAL);
return Result.ofPlanNode(new TopNNode(
context.getIdAllocator().getNextId(),
partial,
single.getCount(),
single.getOrderingScheme(),
FINAL));
}
}