org.apache.hadoop.hive.ql.optimizer.BucketMapJoinOptimizer Maven / Gradle / Ivy
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* 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,
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* 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.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Stack;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.hive.ql.exec.MapJoinOperator;
import org.apache.hadoop.hive.ql.lib.DefaultGraphWalker;
import org.apache.hadoop.hive.ql.lib.DefaultRuleDispatcher;
import org.apache.hadoop.hive.ql.lib.Dispatcher;
import org.apache.hadoop.hive.ql.lib.GraphWalker;
import org.apache.hadoop.hive.ql.lib.Node;
import org.apache.hadoop.hive.ql.lib.NodeProcessor;
import org.apache.hadoop.hive.ql.lib.NodeProcessorCtx;
import org.apache.hadoop.hive.ql.lib.Rule;
import org.apache.hadoop.hive.ql.lib.RuleRegExp;
import org.apache.hadoop.hive.ql.parse.ParseContext;
import org.apache.hadoop.hive.ql.parse.SemanticException;
/**
* this transformation does bucket map join optimization.
*/
public class BucketMapJoinOptimizer extends Transform {
private static final Logger LOG = LoggerFactory.getLogger(GroupByOptimizer.class
.getName());
public BucketMapJoinOptimizer() {
}
public ParseContext transform(ParseContext pctx) throws SemanticException {
Map opRules = new LinkedHashMap();
BucketJoinProcCtx bucketMapJoinOptimizeCtx =
new BucketJoinProcCtx(pctx.getConf());
// process map joins with no reducers pattern
opRules.put(new RuleRegExp("R1",
MapJoinOperator.getOperatorName() + "%"),
getBucketMapjoinProc(pctx));
// The dispatcher fires the processor corresponding to the closest matching
// rule and passes the context along
Dispatcher disp = new DefaultRuleDispatcher(getDefaultProc(), opRules,
bucketMapJoinOptimizeCtx);
GraphWalker ogw = new DefaultGraphWalker(disp);
// Create a list of topop nodes
List topNodes = new ArrayList();
topNodes.addAll(pctx.getTopOps().values());
ogw.startWalking(topNodes, null);
return pctx;
}
private NodeProcessor getBucketMapjoinProc(ParseContext pctx) {
return new BucketMapjoinProc(pctx);
}
private NodeProcessor getDefaultProc() {
return new NodeProcessor() {
@Override
public Object process(Node nd, Stack stack,
NodeProcessorCtx procCtx, Object... nodeOutputs)
throws SemanticException {
return null;
}
};
}
}