/**
* 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.physical;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Stack;
import org.apache.hadoop.hive.ql.Context;
import org.apache.hadoop.hive.ql.exec.ConditionalTask;
import org.apache.hadoop.hive.ql.exec.MapredLocalTask;
import org.apache.hadoop.hive.ql.exec.Operator;
import org.apache.hadoop.hive.ql.exec.Task;
import org.apache.hadoop.hive.ql.exec.TaskFactory;
import org.apache.hadoop.hive.ql.exec.Utilities;
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.lib.TaskGraphWalker;
import org.apache.hadoop.hive.ql.parse.ParseContext;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.plan.ConditionalResolver;
import org.apache.hadoop.hive.ql.plan.ConditionalResolverCommonJoin;
import org.apache.hadoop.hive.ql.plan.ConditionalResolverSkewJoin;
import org.apache.hadoop.hive.ql.plan.ConditionalWork;
import org.apache.hadoop.hive.ql.plan.MapredLocalWork;
import org.apache.hadoop.hive.ql.plan.MapredWork;
import org.apache.hadoop.hive.ql.plan.ConditionalResolverCommonJoin.ConditionalResolverCommonJoinCtx;
import org.apache.hadoop.hive.ql.plan.ConditionalResolverSkewJoin.ConditionalResolverSkewJoinCtx;
/**
* An implementation of PhysicalPlanResolver. It iterator each MapRedTask to see whether the task
* has a local map work if it has, it will move the local work to a new local map join task. Then it
* will make this new generated task depends on current task's parent task and make current task
* depends on this new generated task.
*/
public class MapJoinResolver implements PhysicalPlanResolver {
@Override
public PhysicalContext resolve(PhysicalContext pctx) throws SemanticException {
// create dispatcher and graph walker
Dispatcher disp = new LocalMapJoinTaskDispatcher(pctx);
TaskGraphWalker ogw = new TaskGraphWalker(disp);
// get all the tasks nodes from root task
ArrayList<Node> topNodes = new ArrayList<Node>();
topNodes.addAll(pctx.rootTasks);
// begin to walk through the task tree.
ogw.startWalking(topNodes, null);
return pctx;
}
/**
* Iterator each tasks. If this task has a local work,create a new task for this local work, named
* MapredLocalTask. then make this new generated task depends on current task's parent task, and
* make current task depends on this new generated task
*/
class LocalMapJoinTaskDispatcher implements Dispatcher {
private PhysicalContext physicalContext;
public LocalMapJoinTaskDispatcher(PhysicalContext context) {
super();
physicalContext = context;
}
private void processCurrentTask(Task<? extends Serializable> currTask,
ConditionalTask conditionalTask) throws SemanticException {
// get current mapred work and its local work
MapredWork mapredWork = (MapredWork) currTask.getWork();
MapredLocalWork localwork = mapredWork.getMapLocalWork();
if (localwork != null) {
// get the context info and set up the shared tmp URI
Context ctx = physicalContext.getContext();
String tmpFileURI = Utilities.generateTmpURI(ctx.getLocalTmpFileURI(), currTask.getId());
localwork.setTmpFileURI(tmpFileURI);
String hdfsTmpURI = Utilities.generateTmpURI(ctx.getMRTmpFileURI(), currTask.getId());
mapredWork.setTmpHDFSFileURI(hdfsTmpURI);
// create a task for this local work; right now, this local work is shared
// by the original MapredTask and this new generated MapredLocalTask.
MapredLocalTask localTask = (MapredLocalTask) TaskFactory.get(localwork, physicalContext
.getParseContext().getConf());
// set the backup task from curr task
localTask.setBackupTask(currTask.getBackupTask());
localTask.setBackupChildrenTasks(currTask.getBackupChildrenTasks());
currTask.setBackupChildrenTasks(null);
currTask.setBackupTask(null);
if (currTask.getTaskTag() == Task.CONVERTED_MAPJOIN) {
localTask.setTaskTag(Task.CONVERTED_LOCAL_MAPJOIN);
} else {
localTask.setTaskTag(Task.LOCAL_MAPJOIN);
}
// replace the map join operator to local_map_join operator in the operator tree
// and return all the dummy parent
LocalMapJoinProcCtx localMapJoinProcCtx= adjustLocalTask(localTask);
List<Operator<? extends Serializable>> dummyOps = localMapJoinProcCtx.getDummyParentOp();
// create new local work and setup the dummy ops
MapredLocalWork newLocalWork = new MapredLocalWork();
newLocalWork.setDummyParentOp(dummyOps);
newLocalWork.setTmpFileURI(tmpFileURI);
newLocalWork.setInputFileChangeSensitive(localwork.getInputFileChangeSensitive());
mapredWork.setMapLocalWork(newLocalWork);
// get all parent tasks
List<Task<? extends Serializable>> parentTasks = currTask.getParentTasks();
currTask.setParentTasks(null);
if (parentTasks != null) {
for (Task<? extends Serializable> tsk : parentTasks) {
// make new generated task depends on all the parent tasks of current task.
tsk.addDependentTask(localTask);
// remove the current task from its original parent task's dependent task
tsk.removeDependentTask(currTask);
}
} else {
// in this case, current task is in the root tasks
// so add this new task into root tasks and remove the current task from root tasks
if (conditionalTask == null) {
physicalContext.addToRootTask(localTask);
physicalContext.removeFromRootTask(currTask);
} else {
// set list task
List<Task<? extends Serializable>> listTask = conditionalTask.getListTasks();
ConditionalWork conditionalWork = conditionalTask.getWork();
int index = listTask.indexOf(currTask);
listTask.set(index, localTask);
// set list work
List<Serializable> listWork = (List<Serializable>) conditionalWork.getListWorks();
index = listWork.indexOf(mapredWork);
listWork.set(index, (Serializable) localwork);
conditionalWork.setListWorks(listWork);
ConditionalResolver resolver = conditionalTask.getResolver();
if (resolver instanceof ConditionalResolverSkewJoin) {
// get bigKeysDirToTaskMap
ConditionalResolverSkewJoinCtx context = (ConditionalResolverSkewJoinCtx) conditionalTask
.getResolverCtx();
HashMap<String, Task<? extends Serializable>> bigKeysDirToTaskMap = context
.getDirToTaskMap();
// to avoid concurrent modify the hashmap
HashMap<String, Task<? extends Serializable>> newbigKeysDirToTaskMap = new HashMap<String, Task<? extends Serializable>>();
// reset the resolver
for (Map.Entry<String, Task<? extends Serializable>> entry : bigKeysDirToTaskMap
.entrySet()) {
Task<? extends Serializable> task = entry.getValue();
String key = entry.getKey();
if (task.equals(currTask)) {
newbigKeysDirToTaskMap.put(key, localTask);
} else {
newbigKeysDirToTaskMap.put(key, task);
}
}
context.setDirToTaskMap(newbigKeysDirToTaskMap);
conditionalTask.setResolverCtx(context);
} else if (resolver instanceof ConditionalResolverCommonJoin) {
// get bigKeysDirToTaskMap
ConditionalResolverCommonJoinCtx context = (ConditionalResolverCommonJoinCtx) conditionalTask
.getResolverCtx();
HashMap<String, Task<? extends Serializable>> aliasToWork = context.getAliasToTask();
// to avoid concurrent modify the hashmap
HashMap<String, Task<? extends Serializable>> newAliasToWork = new HashMap<String, Task<? extends Serializable>>();
// reset the resolver
for (Map.Entry<String, Task<? extends Serializable>> entry : aliasToWork.entrySet()) {
Task<? extends Serializable> task = entry.getValue();
String key = entry.getKey();
if (task.equals(currTask)) {
newAliasToWork.put(key, localTask);
} else {
newAliasToWork.put(key, task);
}
}
context.setAliasToTask(newAliasToWork);
conditionalTask.setResolverCtx(context);
}
}
}
// make current task depends on this new generated localMapJoinTask
// now localTask is the parent task of the current task
localTask.addDependentTask(currTask);
}
}
@Override
public Object dispatch(Node nd, Stack<Node> stack, Object... nodeOutputs)
throws SemanticException {
Task<? extends Serializable> currTask = (Task<? extends Serializable>) nd;
// not map reduce task or not conditional task, just skip
if (currTask.isMapRedTask()) {
if (currTask instanceof ConditionalTask) {
// get the list of task
List<Task<? extends Serializable>> taskList = ((ConditionalTask) currTask).getListTasks();
for (Task<? extends Serializable> tsk : taskList) {
if (tsk.isMapRedTask()) {
this.processCurrentTask(tsk, ((ConditionalTask) currTask));
}
}
} else {
this.processCurrentTask(currTask, null);
}
}
return null;
}
// replace the map join operator to local_map_join operator in the operator tree
private LocalMapJoinProcCtx adjustLocalTask(MapredLocalTask task)
throws SemanticException {
LocalMapJoinProcCtx localMapJoinProcCtx = new LocalMapJoinProcCtx(task, physicalContext
.getParseContext());
Map<Rule, NodeProcessor> opRules = new LinkedHashMap<Rule, NodeProcessor>();
opRules.put(new RuleRegExp("R1", "MAPJOIN%"), LocalMapJoinProcFactory.getJoinProc());
// The dispatcher fires the processor corresponding to the closest
// matching rule and passes the context along
Dispatcher disp = new DefaultRuleDispatcher(LocalMapJoinProcFactory.getDefaultProc(),
opRules, localMapJoinProcCtx);
GraphWalker ogw = new DefaultGraphWalker(disp);
// iterator the reducer operator tree
ArrayList<Node> topNodes = new ArrayList<Node>();
topNodes.addAll(task.getWork().getAliasToWork().values());
ogw.startWalking(topNodes, null);
return localMapJoinProcCtx;
}
public PhysicalContext getPhysicalContext() {
return physicalContext;
}
public void setPhysicalContext(PhysicalContext physicalContext) {
this.physicalContext = physicalContext;
}
}
/**
* A container of current task and parse context.
*/
public static class LocalMapJoinProcCtx implements NodeProcessorCtx {
private Task<? extends Serializable> currentTask;
private ParseContext parseCtx;
private List<Operator<? extends Serializable>> dummyParentOp = null;
private boolean isFollowedByGroupBy;
public LocalMapJoinProcCtx(Task<? extends Serializable> task, ParseContext parseCtx) {
currentTask = task;
this.parseCtx = parseCtx;
dummyParentOp = new ArrayList<Operator<? extends Serializable>>();
isFollowedByGroupBy = false;
}
public Task<? extends Serializable> getCurrentTask() {
return currentTask;
}
public void setCurrentTask(Task<? extends Serializable> currentTask) {
this.currentTask = currentTask;
}
public boolean isFollowedByGroupBy() {
return isFollowedByGroupBy;
}
public void setFollowedByGroupBy(boolean isFollowedByGroupBy) {
this.isFollowedByGroupBy = isFollowedByGroupBy;
}
public ParseContext getParseCtx() {
return parseCtx;
}
public void setParseCtx(ParseContext parseCtx) {
this.parseCtx = parseCtx;
}
public void setDummyParentOp(List<Operator<? extends Serializable>> op) {
this.dummyParentOp = op;
}
public List<Operator<? extends Serializable>> getDummyParentOp() {
return this.dummyParentOp;
}
public void addDummyParentOp(Operator<? extends Serializable> op) {
this.dummyParentOp.add(op);
}
}
}