org.apache.flink.runtime.operators.AllGroupReduceDriver Maven / Gradle / Ivy
/*
* 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.flink.runtime.operators;
import org.apache.flink.api.common.ExecutionConfig;
import org.apache.flink.runtime.util.NonReusingMutableToRegularIteratorWrapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.flink.api.common.functions.GroupCombineFunction;
import org.apache.flink.api.common.functions.GroupReduceFunction;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.operators.util.TaskConfig;
import org.apache.flink.runtime.util.ReusingMutableToRegularIteratorWrapper;
import org.apache.flink.util.Collector;
import org.apache.flink.util.MutableObjectIterator;
/**
* GroupReduceDriver task which is executed by a Task Manager. The task has a
* single input and one or multiple outputs. It is provided with a GroupReduceFunction
* implementation or a RichGroupReduceFunction. This Driver performs
* multiple tasks depending on the DriverStrategy. In case of a ALL_GROUP_REDUCE_COMBINE
* it uses the combine function of the supplied user function. In case
* of the ALL_GROUP_REDUCE, it uses the reduce function of the supplied user function to
* process all elements. In either case, the function is executed on all elements.
*
* The AllGroupReduceDriver creates an iterator over all records from its input.
* The iterator is handed to the reduce() method of the GroupReduceFunction.
*
* @see org.apache.flink.api.common.functions.GroupReduceFunction
*/
public class AllGroupReduceDriver implements Driver, OT> {
private static final Logger LOG = LoggerFactory.getLogger(AllGroupReduceDriver.class);
private TaskContext, OT> taskContext;
private MutableObjectIterator input;
private TypeSerializer serializer;
private DriverStrategy strategy;
private boolean objectReuseEnabled = false;
// ------------------------------------------------------------------------
@Override
public void setup(TaskContext, OT> context) {
this.taskContext = context;
}
@Override
public int getNumberOfInputs() {
return 1;
}
@Override
public Class> getStubType() {
@SuppressWarnings("unchecked")
final Class> clazz = (Class>) (Class) GroupReduceFunction.class;
return clazz;
}
@Override
public int getNumberOfDriverComparators() {
return 0;
}
// --------------------------------------------------------------------------------------------
@Override
public void prepare() throws Exception {
final TaskConfig config = this.taskContext.getTaskConfig();
this.strategy = config.getDriverStrategy();
switch (this.strategy) {
case ALL_GROUP_REDUCE_COMBINE:
if (!(this.taskContext.getStub() instanceof GroupCombineFunction)) {
throw new Exception("Using combiner on a UDF that does not implement the combiner interface " + GroupCombineFunction.class.getName());
}
case ALL_GROUP_REDUCE:
case ALL_GROUP_COMBINE:
break;
default:
throw new Exception("Unrecognized driver strategy for AllGroupReduce driver: " + this.strategy.name());
}
this.serializer = this.taskContext.getInputSerializer(0).getSerializer();
this.input = this.taskContext.getInput(0);
ExecutionConfig executionConfig = taskContext.getExecutionConfig();
this.objectReuseEnabled = executionConfig.isObjectReuseEnabled();
if (LOG.isDebugEnabled()) {
LOG.debug("AllGroupReduceDriver object reuse: " + (this.objectReuseEnabled ? "ENABLED" : "DISABLED") + ".");
}
}
@Override
public void run() throws Exception {
if (LOG.isDebugEnabled()) {
LOG.debug(this.taskContext.formatLogString("AllGroupReduceDriver preprocessing done. Running Reducer code."));
}
if (objectReuseEnabled) {
final ReusingMutableToRegularIteratorWrapper inIter = new ReusingMutableToRegularIteratorWrapper(this.input, this.serializer);
// single UDF call with the single group
if (inIter.hasNext()) {
if (strategy == DriverStrategy.ALL_GROUP_REDUCE) {
final GroupReduceFunction reducer = this.taskContext.getStub();
final Collector output = this.taskContext.getOutputCollector();
reducer.reduce(inIter, output);
} else if (strategy == DriverStrategy.ALL_GROUP_REDUCE_COMBINE || strategy == DriverStrategy.ALL_GROUP_COMBINE) {
@SuppressWarnings("unchecked") final GroupCombineFunction combiner = (GroupCombineFunction) this.taskContext.getStub();
final Collector output = this.taskContext.getOutputCollector();
combiner.combine(inIter, output);
} else {
throw new Exception("The strategy " + strategy + " is unknown to this driver.");
}
}
} else {
final NonReusingMutableToRegularIteratorWrapper inIter = new NonReusingMutableToRegularIteratorWrapper(this.input, this.serializer);
// single UDF call with the single group
if (inIter.hasNext()) {
if (strategy == DriverStrategy.ALL_GROUP_REDUCE) {
final GroupReduceFunction reducer = this.taskContext.getStub();
final Collector output = this.taskContext.getOutputCollector();
reducer.reduce(inIter, output);
} else if (strategy == DriverStrategy.ALL_GROUP_REDUCE_COMBINE || strategy == DriverStrategy.ALL_GROUP_COMBINE) {
@SuppressWarnings("unchecked") final GroupCombineFunction combiner = (GroupCombineFunction) this.taskContext.getStub();
final Collector output = this.taskContext.getOutputCollector();
combiner.combine(inIter, output);
} else {
throw new Exception("The strategy " + strategy + " is unknown to this driver.");
}
}
}
}
@Override
public void cleanup() {}
@Override
public void cancel() {}
}