/*
* 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.sort.NonReusingSortMergeCoGroupIterator;
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.CoGroupFunction;
import org.apache.flink.api.common.typeutils.TypeComparator;
import org.apache.flink.api.common.typeutils.TypePairComparatorFactory;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.operators.sort.ReusingSortMergeCoGroupIterator;
import org.apache.flink.runtime.operators.util.CoGroupTaskIterator;
import org.apache.flink.runtime.operators.util.TaskConfig;
import org.apache.flink.util.Collector;
import org.apache.flink.util.MutableObjectIterator;
/**
* CoGroup task which is executed by a Task Manager. The task has two
* inputs and one or multiple outputs. It is provided with a CoGroupFunction
* implementation.
* <p>
* The CoGroupTask group all pairs that share the same key from both inputs. Each for each key, the sets of values that
* were pair with that key of both inputs are handed to the <code>coGroup()</code> method of the CoGroupFunction.
*
* @see org.apache.flink.api.common.functions.CoGroupFunction
*/
public class CoGroupDriver<IT1, IT2, OT> implements Driver<CoGroupFunction<IT1, IT2, OT>, OT> {
private static final Logger LOG = LoggerFactory.getLogger(CoGroupDriver.class);
private TaskContext<CoGroupFunction<IT1, IT2, OT>, OT> taskContext;
private CoGroupTaskIterator<IT1, IT2> coGroupIterator; // the iterator that does the actual cogroup
private volatile boolean running;
private boolean objectReuseEnabled = false;
// ------------------------------------------------------------------------
@Override
public void setup(TaskContext<CoGroupFunction<IT1, IT2, OT>, OT> context) {
this.taskContext = context;
this.running = true;
}
@Override
public int getNumberOfInputs() {
return 2;
}
@Override
public Class<CoGroupFunction<IT1, IT2, OT>> getStubType() {
@SuppressWarnings("unchecked")
final Class<CoGroupFunction<IT1, IT2, OT>> clazz = (Class<CoGroupFunction<IT1, IT2, OT>>) (Class<?>) CoGroupFunction.class;
return clazz;
}
@Override
public int getNumberOfDriverComparators() {
return 2;
}
@Override
public void prepare() throws Exception
{
final TaskConfig config = this.taskContext.getTaskConfig();
if (config.getDriverStrategy() != DriverStrategy.CO_GROUP) {
throw new Exception("Unrecognized driver strategy for CoGoup driver: " + config.getDriverStrategy().name());
}
final Counter numRecordsIn = this.taskContext.getMetricGroup().getIOMetricGroup().getNumRecordsInCounter();
final MutableObjectIterator<IT1> in1 = new CountingMutableObjectIterator<>(this.taskContext.<IT1>getInput(0), numRecordsIn);
final MutableObjectIterator<IT2> in2 = new CountingMutableObjectIterator<>(this.taskContext.<IT2>getInput(1), numRecordsIn);
// get the key positions and types
final TypeSerializer<IT1> serializer1 = this.taskContext.<IT1>getInputSerializer(0).getSerializer();
final TypeSerializer<IT2> serializer2 = this.taskContext.<IT2>getInputSerializer(1).getSerializer();
final TypeComparator<IT1> groupComparator1 = this.taskContext.getDriverComparator(0);
final TypeComparator<IT2> groupComparator2 = this.taskContext.getDriverComparator(1);
final TypePairComparatorFactory<IT1, IT2> pairComparatorFactory = config.getPairComparatorFactory(
this.taskContext.getUserCodeClassLoader());
if (pairComparatorFactory == null) {
throw new Exception("Missing pair comparator factory for CoGroup driver");
}
ExecutionConfig executionConfig = taskContext.getExecutionConfig();
this.objectReuseEnabled = executionConfig.isObjectReuseEnabled();
if (LOG.isDebugEnabled()) {
LOG.debug("CoGroupDriver object reuse: " + (this.objectReuseEnabled ? "ENABLED" : "DISABLED") + ".");
}
if (objectReuseEnabled) {
// create CoGropuTaskIterator according to provided local strategy.
this.coGroupIterator = new ReusingSortMergeCoGroupIterator<IT1, IT2>(
in1, in2,
serializer1, groupComparator1,
serializer2, groupComparator2,
pairComparatorFactory.createComparator12(groupComparator1, groupComparator2));
} else {
// create CoGropuTaskIterator according to provided local strategy.
this.coGroupIterator = new NonReusingSortMergeCoGroupIterator<IT1, IT2>(
in1, in2,
serializer1, groupComparator1,
serializer2, groupComparator2,
pairComparatorFactory.createComparator12(groupComparator1, groupComparator2));
}
// open CoGroupTaskIterator - this triggers the sorting and blocks until the iterator is ready
this.coGroupIterator.open();
if (LOG.isDebugEnabled()) {
LOG.debug(this.taskContext.formatLogString("CoGroup task iterator ready."));
}
}
@Override
public void run() throws Exception
{
final Counter numRecordsOut = this.taskContext.getMetricGroup().getIOMetricGroup().getNumRecordsOutCounter();
final CoGroupFunction<IT1, IT2, OT> coGroupStub = this.taskContext.getStub();
final Collector<OT> collector = new CountingCollector<>(this.taskContext.getOutputCollector(), numRecordsOut);
final CoGroupTaskIterator<IT1, IT2> coGroupIterator = this.coGroupIterator;
while (this.running && coGroupIterator.next()) {
coGroupStub.coGroup(coGroupIterator.getValues1(), coGroupIterator.getValues2(), collector);
}
}
@Override
public void cleanup() throws Exception {
if (this.coGroupIterator != null) {
this.coGroupIterator.close();
this.coGroupIterator = null;
}
}
@Override
public void cancel() throws Exception {
this.running = false;
cleanup();
}
}