org.apache.flink.runtime.operators.GroupReduceDriver 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,
* 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.metrics.Counter;
import org.apache.flink.runtime.operators.util.metrics.CountingCollector;
import org.apache.flink.runtime.operators.util.metrics.CountingMutableObjectIterator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.flink.api.common.functions.GroupReduceFunction;
import org.apache.flink.api.common.typeutils.TypeComparator;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.operators.util.TaskConfig;
import org.apache.flink.runtime.util.ReusingKeyGroupedIterator;
import org.apache.flink.runtime.util.NonReusingKeyGroupedIterator;
import org.apache.flink.util.Collector;
import org.apache.flink.util.MutableObjectIterator;
/**
* GroupReduce 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.
*
* The GroupReduceDriver creates a iterator over all records from its input. The iterator returns all records grouped by their
* key. The iterator is handed to the reduce()
method of the GroupReduceFunction.
*
* @see org.apache.flink.api.common.functions.GroupReduceFunction
*/
public class GroupReduceDriver implements Driver, OT> {
private static final Logger LOG = LoggerFactory.getLogger(GroupReduceDriver.class);
private TaskContext, OT> taskContext;
private MutableObjectIterator input;
private TypeSerializer serializer;
private TypeComparator comparator;
private volatile boolean running;
private boolean objectReuseEnabled = false;
// ------------------------------------------------------------------------
@Override
public void setup(TaskContext, OT> context) {
this.taskContext = context;
this.running = true;
}
@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 1;
}
// --------------------------------------------------------------------------------------------
@Override
public void prepare() throws Exception {
TaskConfig config = this.taskContext.getTaskConfig();
if (config.getDriverStrategy() != DriverStrategy.SORTED_GROUP_REDUCE) {
throw new Exception("Unrecognized driver strategy for GroupReduce driver: " + config.getDriverStrategy().name());
}
final Counter numRecordsIn = this.taskContext.getMetricGroup().counter("numRecordsIn");
this.serializer = this.taskContext.getInputSerializer(0).getSerializer();
this.comparator = this.taskContext.getDriverComparator(0);
this.input = new CountingMutableObjectIterator<>(this.taskContext.getInput(0), numRecordsIn);
ExecutionConfig executionConfig = taskContext.getExecutionConfig();
this.objectReuseEnabled = executionConfig.isObjectReuseEnabled();
if (LOG.isDebugEnabled()) {
LOG.debug("GroupReduceDriver object reuse: " + (this.objectReuseEnabled ? "ENABLED" : "DISABLED") + ".");
}
}
@Override
public void run() throws Exception {
if (LOG.isDebugEnabled()) {
LOG.debug(this.taskContext.formatLogString("GroupReducer preprocessing done. Running GroupReducer code."));
}
final Counter numRecordsOut = this.taskContext.getMetricGroup().counter("numRecordsOut");
// cache references on the stack
final GroupReduceFunction stub = this.taskContext.getStub();
final Collector output = new CountingCollector<>(this.taskContext.getOutputCollector(), numRecordsOut);
if (objectReuseEnabled) {
final ReusingKeyGroupedIterator iter = new ReusingKeyGroupedIterator(this.input, this.serializer, this.comparator);
// run stub implementation
while (this.running && iter.nextKey()) {
stub.reduce(iter.getValues(), output);
}
}
else {
final NonReusingKeyGroupedIterator iter = new NonReusingKeyGroupedIterator(this.input, this.comparator);
// run stub implementation
while (this.running && iter.nextKey()) {
stub.reduce(iter.getValues(), output);
}
}
}
@Override
public void cleanup() {}
@Override
public void cancel() {
this.running = false;
}
}