/**
* 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.views;
import java.util.Collections;
import java.util.List;
import org.apache.calcite.plan.RelOptMaterialization;
import org.apache.calcite.plan.RelOptMaterializations;
import org.apache.calcite.plan.RelOptPlanner;
import org.apache.calcite.plan.RelOptRule;
import org.apache.calcite.plan.RelOptRuleCall;
import org.apache.calcite.plan.volcano.VolcanoPlanner;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rel.core.Filter;
import org.apache.calcite.rel.core.Project;
import org.apache.calcite.rel.core.TableScan;
import org.apache.calcite.tools.RelBuilderFactory;
import org.apache.hadoop.hive.ql.optimizer.calcite.HiveRelFactories;
import com.google.common.collect.ImmutableList;
/**
* Planner rule that replaces (if possible)
* a {@link org.apache.calcite.rel.core.Project}
* on a {@link org.apache.calcite.rel.core.Filter}
* on a {@link org.apache.calcite.rel.core.TableScan}
* to use a Materialized View.
*/
public class HiveMaterializedViewFilterScanRule extends RelOptRule {
public static final HiveMaterializedViewFilterScanRule INSTANCE =
new HiveMaterializedViewFilterScanRule(HiveRelFactories.HIVE_BUILDER);
//~ Constructors -----------------------------------------------------------
/** Creates a HiveMaterializedViewFilterScanRule. */
protected HiveMaterializedViewFilterScanRule(RelBuilderFactory relBuilderFactory) {
super(operand(Project.class, operand(Filter.class, operand(TableScan.class, null, none()))),
relBuilderFactory, "MaterializedViewFilterScanRule");
}
//~ Methods ----------------------------------------------------------------
public void onMatch(RelOptRuleCall call) {
final Project project = call.rel(0);
final Filter filter = call.rel(1);
final TableScan scan = call.rel(2);
apply(call, project, filter, scan);
}
protected void apply(RelOptRuleCall call, Project project, Filter filter, TableScan scan) {
RelOptPlanner planner = call.getPlanner();
List<RelOptMaterialization> materializations =
(planner instanceof VolcanoPlanner)
? ((VolcanoPlanner) planner).getMaterializations()
: ImmutableList.<RelOptMaterialization>of();
if (!materializations.isEmpty()) {
RelNode root = project.copy(project.getTraitSet(), Collections.singletonList(
filter.copy(filter.getTraitSet(), Collections.singletonList(
(RelNode) scan))));
// Costing is done in transformTo(), so we call it repeatedly with all applicable
// materialized views and cheapest one will be picked
List<RelOptMaterialization> applicableMaterializations =
RelOptMaterializations.getApplicableMaterializations(root, materializations);
for (RelOptMaterialization materialization : applicableMaterializations) {
List<RelNode> subs = new MaterializedViewSubstitutionVisitor(
materialization.queryRel, root, relBuilderFactory).go(materialization.tableRel);
for (RelNode s : subs) {
call.transformTo(s);
}
}
}
}
}