algebricks/algebricks-rewriter/src/main/java/org/apache/hyracks/algebricks/rewriter/rules/SetExecutionModeRule.java

/*
 * 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.hyracks.algebricks.rewriter.rules;

import org.apache.commons.lang3.mutable.Mutable;

import org.apache.hyracks.algebricks.common.exceptions.NotImplementedException;
import org.apache.hyracks.algebricks.core.algebra.base.ILogicalOperator;
import org.apache.hyracks.algebricks.core.algebra.base.IOptimizationContext;
import org.apache.hyracks.algebricks.core.algebra.operators.logical.AbstractLogicalOperator;
import org.apache.hyracks.algebricks.core.algebra.util.OperatorManipulationUtil;
import org.apache.hyracks.algebricks.core.rewriter.base.IAlgebraicRewriteRule;

/**
 * This rule sets the executionMode property of an operator, w/o introducing
 * EXCHANGE operators in the plan. Previously, i.e. before having physical
 * optimizations in place, we were using the IntroduceExchangeRule, which was
 * doing both, to both set excutionMode and introduce data exchange ops.
 *
 * @author Nicola
 */
public class SetExecutionModeRule implements IAlgebraicRewriteRule {

    @Override
    public boolean rewritePost(Mutable<ILogicalOperator> opRef, IOptimizationContext context) {
        AbstractLogicalOperator op = (AbstractLogicalOperator) opRef.getValue();
        boolean changed = OperatorManipulationUtil.setOperatorMode(op);
        if (op.getExecutionMode() == AbstractLogicalOperator.ExecutionMode.UNPARTITIONED
                || op.getExecutionMode() == AbstractLogicalOperator.ExecutionMode.LOCAL) {
            return changed;
        }
        switch (op.getOperatorTag()) {
        // case DISTINCT:
        // case AGGREGATE:
        // case GROUP:
        // case ORDER:
        // case INNERJOIN:
        // case LEFTOUTERJOIN: {
        // op.setExecutionMode(ExecutionMode.GLOBAL);
        // return true;
        // }

            case PARTITIONINGSPLIT: {
                throw new NotImplementedException();
            }
            default: {
                return changed;
            }
        }

    }

    @Override
    public boolean rewritePre(Mutable<ILogicalOperator> opRef, IOptimizationContext context) {
        return false;
    }

}