/**
* 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;
import java.util.ArrayList;
import java.util.List;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.ql.optimizer.lineage.Generator;
import org.apache.hadoop.hive.ql.optimizer.pcr.PartitionConditionRemover;
import org.apache.hadoop.hive.ql.optimizer.ppr.PartitionPruner;
import org.apache.hadoop.hive.ql.optimizer.unionproc.UnionProcessor;
import org.apache.hadoop.hive.ql.parse.ParseContext;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.ppd.PredicatePushDown;
/**
* Implementation of the optimizer.
*/
public class Optimizer {
private ParseContext pctx;
private List<Transform> transformations;
/**
* Create the list of transformations.
*
* @param hiveConf
*/
public void initialize(HiveConf hiveConf) {
transformations = new ArrayList<Transform>();
// Add the transformation that computes the lineage information.
transformations.add(new Generator());
if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVEOPTCP)) {
transformations.add(new ColumnPruner());
}
if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVEOPTPPD)) {
transformations.add(new PredicatePushDown());
transformations.add(new PartitionPruner());
transformations.add(new PartitionConditionRemover());
}
if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVEOPTGROUPBY)) {
transformations.add(new GroupByOptimizer());
}
transformations.add(new SamplePruner());
transformations.add(new MapJoinProcessor());
if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVEOPTBUCKETMAPJOIN)) {
transformations.add(new BucketMapJoinOptimizer());
if(HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVEOPTSORTMERGEBUCKETMAPJOIN)) {
transformations.add(new SortedMergeBucketMapJoinOptimizer());
}
}
transformations.add(new UnionProcessor());
transformations.add(new JoinReorder());
if(HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVEOPTREDUCEDEDUPLICATION)) {
transformations.add(new ReduceSinkDeDuplication());
}
}
/**
* Invoke all the transformations one-by-one, and alter the query plan.
*
* @return ParseContext
* @throws SemanticException
*/
public ParseContext optimize() throws SemanticException {
for (Transform t : transformations) {
pctx = t.transform(pctx);
}
return pctx;
}
/**
* @return the pctx
*/
public ParseContext getPctx() {
return pctx;
}
/**
* @param pctx
* the pctx to set
*/
public void setPctx(ParseContext pctx) {
this.pctx = pctx;
}
}