/**
* 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 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 org.apache.hadoop.hive.ql.optimizer.calcite.rules;
import java.util.Set;
import org.apache.calcite.plan.RelOptRuleCall;
import org.apache.calcite.rel.core.Project;
import org.apache.calcite.rel.rules.ProjectMergeRule;
import org.apache.calcite.rex.RexNode;
import org.apache.calcite.rex.RexOver;
import org.apache.calcite.tools.RelBuilderFactory;
import org.apache.hadoop.hive.ql.optimizer.calcite.HiveCalciteUtil;
import org.apache.hadoop.hive.ql.optimizer.calcite.HiveRelFactories;
/**
* ProjectMergeRule merges a {@link org.apache.calcite.rel.core.Project} into
* another {@link org.apache.calcite.rel.core.Project},
* provided the projects aren't projecting identical sets of input references.
*/
public class HiveProjectMergeRule extends ProjectMergeRule {
public static final HiveProjectMergeRule INSTANCE =
new HiveProjectMergeRule(true, HiveRelFactories.HIVE_BUILDER);
public static final HiveProjectMergeRule INSTANCE_NO_FORCE =
new HiveProjectMergeRule(false, HiveRelFactories.HIVE_BUILDER);
private HiveProjectMergeRule(boolean force, RelBuilderFactory relBuilderFactory) {
super(force, relBuilderFactory);
}
@Override
public boolean matches(RelOptRuleCall call) {
// Currently we do not support merging windowing functions with other
// windowing functions i.e. embedding windowing functions within each
// other
final Project topProject = call.rel(0);
final Project bottomProject = call.rel(1);
for (RexNode expr : topProject.getChildExps()) {
if (expr instanceof RexOver) {
Set<Integer> positions = HiveCalciteUtil.getInputRefs(expr);
for (int pos : positions) {
if (bottomProject.getChildExps().get(pos) instanceof RexOver) {
return false;
}
}
}
}
return super.matches(call);
}
}