/**
* 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.List;
import java.util.Map;
import java.util.Stack;
import org.apache.hadoop.fs.ContentSummary;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hive.ql.Context;
import org.apache.hadoop.hive.ql.exec.ConditionalTask;
import org.apache.hadoop.hive.ql.exec.Task;
import org.apache.hadoop.hive.ql.exec.Utilities;
import org.apache.hadoop.hive.ql.exec.mr.MapRedTask;
import org.apache.hadoop.hive.ql.lib.Dispatcher;
import org.apache.hadoop.hive.ql.lib.Node;
import org.apache.hadoop.hive.ql.lib.TaskGraphWalker.TaskGraphWalkerContext;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.apache.hadoop.hive.ql.plan.MapWork;
/**
* Common iteration methods for converting joins and sort-merge joins.
*/
public abstract class AbstractJoinTaskDispatcher implements Dispatcher {
protected final PhysicalContext physicalContext;
public AbstractJoinTaskDispatcher(PhysicalContext context) {
physicalContext = context;
}
public abstract Task<? extends Serializable> processCurrentTask(MapRedTask currTask,
ConditionalTask conditionalTask, Context context)
throws SemanticException;
protected void replaceTaskWithConditionalTask(
Task<? extends Serializable> currTask, ConditionalTask cndTsk) {
// add this task into task tree
// set 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(cndTsk);
// remove the current task from its original parent task's dependent task
tsk.removeDependentTask(currTask);
}
} else {
// remove from current root task and add conditional task to root tasks
physicalContext.removeFromRootTask(currTask);
physicalContext.addToRootTask(cndTsk);
}
// set all child tasks
List<Task<? extends Serializable>> oldChildTasks = currTask.getChildTasks();
if (oldChildTasks != null) {
for (Task<? extends Serializable> tsk : cndTsk.getListTasks()) {
if (tsk.equals(currTask)) {
continue;
}
for (Task<? extends Serializable> oldChild : oldChildTasks) {
tsk.addDependentTask(oldChild);
}
}
}
}
// Replace the task with the new task. Copy the children and parents of the old
// task to the new task.
protected void replaceTask(
Task<? extends Serializable> currTask, Task<? extends Serializable> newTask) {
// add this task into task tree
// set all parent tasks
List<Task<? extends Serializable>> parentTasks = currTask.getParentTasks();
currTask.setParentTasks(null);
if (parentTasks != null) {
for (Task<? extends Serializable> tsk : parentTasks) {
// remove the current task from its original parent task's dependent task
tsk.removeDependentTask(currTask);
// make new generated task depends on all the parent tasks of current task.
tsk.addDependentTask(newTask);
}
} else {
// remove from current root task and add conditional task to root tasks
physicalContext.removeFromRootTask(currTask);
physicalContext.addToRootTask(newTask);
}
// set all child tasks
List<Task<? extends Serializable>> oldChildTasks = currTask.getChildTasks();
currTask.setChildTasks(null);
if (oldChildTasks != null) {
for (Task<? extends Serializable> tsk : oldChildTasks) {
// remove the current task from its original parent task's dependent task
tsk.getParentTasks().remove(currTask);
// make new generated task depends on all the parent tasks of current task.
newTask.addDependentTask(tsk);
}
}
}
public long getTotalKnownInputSize(Context context, MapWork currWork,
Map<Path, ArrayList<String>> pathToAliases,
HashMap<String, Long> aliasToSize) throws SemanticException {
try {
// go over all the input paths, and calculate a known total size, known
// size for each input alias.
Utilities.getInputSummary(context, currWork, null).getLength();
// set alias to size mapping, this can be used to determine if one table
// is chosen as big table, what's the total size of left tables, which
// are going to be small tables.
long aliasTotalKnownInputSize = 0L;
for (Map.Entry<Path, ArrayList<String>> entry : pathToAliases.entrySet()) {
Path path = entry.getKey();
List<String> aliasList = entry.getValue();
ContentSummary cs = context.getCS(path);
if (cs != null) {
long size = cs.getLength();
for (String alias : aliasList) {
aliasTotalKnownInputSize += size;
Long es = aliasToSize.get(alias);
if (es == null) {
es = new Long(0);
}
es += size;
aliasToSize.put(alias, es);
}
}
}
return aliasTotalKnownInputSize;
} catch (Exception e) {
e.printStackTrace();
throw new SemanticException("Generate Map Join Task Error: " + e.getMessage());
}
}
@Override
public Object dispatch(Node nd, Stack<Node> stack, Object... nodeOutputs)
throws SemanticException {
if (nodeOutputs == null || nodeOutputs.length == 0) {
throw new SemanticException("No Dispatch Context");
}
TaskGraphWalkerContext walkerCtx = (TaskGraphWalkerContext) nodeOutputs[0];
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()) {
Task<? extends Serializable> newTask = this.processCurrentTask((MapRedTask) tsk,
((ConditionalTask) currTask), physicalContext.getContext());
walkerCtx.addToDispatchList(newTask);
}
}
} else {
Task<? extends Serializable> newTask =
this.processCurrentTask((MapRedTask) currTask, null, physicalContext.getContext());
walkerCtx.addToDispatchList(newTask);
}
}
return null;
}
}