[GitHub] [flink-benchmarks] rkhachatryan commented on a change in pull request #3: [FLINK-18905] Provide basic benchmarks for MultipleInputStreamOperator

[GitBox <gi...@apache.org>]

rkhachatryan commented on a change in pull request #3:
URL: https://github.com/apache/flink-benchmarks/pull/3#discussion_r479216456



##########
File path: src/main/java/org/apache/flink/benchmark/MultipleInputBenchmark.java
##########
@@ -0,0 +1,161 @@
+/*
+ * 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.benchmark;
+
+import org.apache.flink.api.common.restartstrategy.RestartStrategies;
+import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
+import org.apache.flink.benchmark.functions.LongSource;
+import org.apache.flink.benchmark.functions.QueuingLongSource;
+import org.apache.flink.streaming.api.datastream.DataStreamSource;
+import org.apache.flink.streaming.api.datastream.MultipleConnectedStreams;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.sink.DiscardingSink;
+import org.apache.flink.streaming.api.operators.AbstractInput;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperatorFactory;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperatorV2;
+import org.apache.flink.streaming.api.operators.Input;
+import org.apache.flink.streaming.api.operators.MultipleInputStreamOperator;
+import org.apache.flink.streaming.api.operators.StreamOperator;
+import org.apache.flink.streaming.api.operators.StreamOperatorParameters;
+import org.apache.flink.streaming.api.transformations.MultipleInputTransformation;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.OperationsPerInvocation;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+import org.openjdk.jmh.runner.options.VerboseMode;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class MultipleInputBenchmark extends BenchmarkBase {
+
+	public static final int RECORDS_PER_INVOCATION = TwoInputBenchmark.RECORDS_PER_INVOCATION;
+	public static final int ONE_IDLE_RECORDS_PER_INVOCATION = TwoInputBenchmark.ONE_IDLE_RECORDS_PER_INVOCATION;
+	public static final long CHECKPOINT_INTERVAL_MS = TwoInputBenchmark.CHECKPOINT_INTERVAL_MS;
+
+	public static void main(String[] args)
+		throws RunnerException {
+		Options options = new OptionsBuilder()
+			.verbosity(VerboseMode.NORMAL)
+			.include(".*" + MultipleInputBenchmark.class.getSimpleName() + ".*")
+			.build();
+
+		new Runner(options).run();
+	}
+
+	@Benchmark
+	@OperationsPerInvocation(RECORDS_PER_INVOCATION)
+	public void multiInputMapSink(FlinkEnvironmentContext context) throws Exception {
+
+		StreamExecutionEnvironment env = context.env;
+
+		env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
+		env.setParallelism(1);
+		env.setRestartStrategy(RestartStrategies.noRestart());
+
+		// Setting buffer timeout to 1 is an attempt to improve twoInputMapSink benchmark stability.
+		// Without 1ms buffer timeout, some JVM forks are much slower then others, making results
+		// unstable and unreliable.
+		env.setBufferTimeout(1);
+
+		long numRecordsPerInput = RECORDS_PER_INVOCATION / 2;
+		DataStreamSource<Long> source1 = env.addSource(new LongSource(numRecordsPerInput));
+		DataStreamSource<Long> source2 = env.addSource(new LongSource(numRecordsPerInput));
+		connectAndDiscard(env, source1, source2);
+
+		env.execute();
+	}
+
+	@Benchmark
+	@OperationsPerInvocation(ONE_IDLE_RECORDS_PER_INVOCATION)
+	public void multiInputOneIdleMapSink(FlinkEnvironmentContext context) throws Exception {
+
+		StreamExecutionEnvironment env = context.env;
+		env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
+		env.setParallelism(1);
+
+		QueuingLongSource.reset();
+		DataStreamSource<Long> source1 = env.addSource(new QueuingLongSource(1, ONE_IDLE_RECORDS_PER_INVOCATION - 1));
+		DataStreamSource<Long> source2 = env.addSource(new QueuingLongSource(2, 1));
+		connectAndDiscard(env, source1, source2);
+
+		env.execute();
+	}
+
+	private void connectAndDiscard(
+			StreamExecutionEnvironment env,
+			DataStreamSource<Long> source1,
+			DataStreamSource<Long> source2) {
+		MultipleInputTransformation<Long> transform = new MultipleInputTransformation<>(
+				"custom operator",
+				new MultiplyByTwoOperatorFactory(),
+				BasicTypeInfo.LONG_TYPE_INFO,
+				1);
+
+		transform.addInput(source1.getTransformation());
+		transform.addInput(source2.getTransformation());
+
+		env.addOperator(transform);
+		new MultipleConnectedStreams(env)
+				.transform(transform)
+				.addSink(new DiscardingSink<>());
+	}
+
+	public static class MultiplyByTwoOperatorFactory extends AbstractStreamOperatorFactory<Long> {
+		@Override
+		public <T extends StreamOperator<Long>> T createStreamOperator(StreamOperatorParameters<Long> parameters) {
+			return (T) new MultiplyByTwoOperator(parameters);

Review comment:
       Can you suppress compiler warning (or fix typing) here and in some other places in this file?

##########
File path: src/main/java/org/apache/flink/benchmark/MultipleInputBenchmark.java
##########
@@ -0,0 +1,161 @@
+/*
+ * 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.benchmark;
+
+import org.apache.flink.api.common.restartstrategy.RestartStrategies;
+import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
+import org.apache.flink.benchmark.functions.LongSource;
+import org.apache.flink.benchmark.functions.QueuingLongSource;
+import org.apache.flink.streaming.api.datastream.DataStreamSource;
+import org.apache.flink.streaming.api.datastream.MultipleConnectedStreams;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.sink.DiscardingSink;
+import org.apache.flink.streaming.api.operators.AbstractInput;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperatorFactory;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperatorV2;
+import org.apache.flink.streaming.api.operators.Input;
+import org.apache.flink.streaming.api.operators.MultipleInputStreamOperator;
+import org.apache.flink.streaming.api.operators.StreamOperator;
+import org.apache.flink.streaming.api.operators.StreamOperatorParameters;
+import org.apache.flink.streaming.api.transformations.MultipleInputTransformation;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.OperationsPerInvocation;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+import org.openjdk.jmh.runner.options.VerboseMode;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class MultipleInputBenchmark extends BenchmarkBase {
+
+	public static final int RECORDS_PER_INVOCATION = TwoInputBenchmark.RECORDS_PER_INVOCATION;
+	public static final int ONE_IDLE_RECORDS_PER_INVOCATION = TwoInputBenchmark.ONE_IDLE_RECORDS_PER_INVOCATION;
+	public static final long CHECKPOINT_INTERVAL_MS = TwoInputBenchmark.CHECKPOINT_INTERVAL_MS;
+
+	public static void main(String[] args)
+		throws RunnerException {
+		Options options = new OptionsBuilder()
+			.verbosity(VerboseMode.NORMAL)
+			.include(".*" + MultipleInputBenchmark.class.getSimpleName() + ".*")
+			.build();
+
+		new Runner(options).run();
+	}
+
+	@Benchmark
+	@OperationsPerInvocation(RECORDS_PER_INVOCATION)
+	public void multiInputMapSink(FlinkEnvironmentContext context) throws Exception {
+
+		StreamExecutionEnvironment env = context.env;
+
+		env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
+		env.setParallelism(1);
+		env.setRestartStrategy(RestartStrategies.noRestart());
+
+		// Setting buffer timeout to 1 is an attempt to improve twoInputMapSink benchmark stability.
+		// Without 1ms buffer timeout, some JVM forks are much slower then others, making results
+		// unstable and unreliable.
+		env.setBufferTimeout(1);
+
+		long numRecordsPerInput = RECORDS_PER_INVOCATION / 2;
+		DataStreamSource<Long> source1 = env.addSource(new LongSource(numRecordsPerInput));
+		DataStreamSource<Long> source2 = env.addSource(new LongSource(numRecordsPerInput));
+		connectAndDiscard(env, source1, source2);
+
+		env.execute();
+	}
+
+	@Benchmark
+	@OperationsPerInvocation(ONE_IDLE_RECORDS_PER_INVOCATION)
+	public void multiInputOneIdleMapSink(FlinkEnvironmentContext context) throws Exception {
+
+		StreamExecutionEnvironment env = context.env;
+		env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
+		env.setParallelism(1);
+
+		QueuingLongSource.reset();
+		DataStreamSource<Long> source1 = env.addSource(new QueuingLongSource(1, ONE_IDLE_RECORDS_PER_INVOCATION - 1));
+		DataStreamSource<Long> source2 = env.addSource(new QueuingLongSource(2, 1));
+		connectAndDiscard(env, source1, source2);
+
+		env.execute();
+	}
+
+	private void connectAndDiscard(
+			StreamExecutionEnvironment env,
+			DataStreamSource<Long> source1,
+			DataStreamSource<Long> source2) {
+		MultipleInputTransformation<Long> transform = new MultipleInputTransformation<>(
+				"custom operator",
+				new MultiplyByTwoOperatorFactory(),
+				BasicTypeInfo.LONG_TYPE_INFO,
+				1);
+
+		transform.addInput(source1.getTransformation());
+		transform.addInput(source2.getTransformation());
+
+		env.addOperator(transform);
+		new MultipleConnectedStreams(env)
+				.transform(transform)
+				.addSink(new DiscardingSink<>());
+	}
+
+	public static class MultiplyByTwoOperatorFactory extends AbstractStreamOperatorFactory<Long> {
+		@Override
+		public <T extends StreamOperator<Long>> T createStreamOperator(StreamOperatorParameters<Long> parameters) {
+			return (T) new MultiplyByTwoOperator(parameters);
+		}
+
+		@Override
+		public Class<? extends StreamOperator> getStreamOperatorClass(ClassLoader classLoader) {
+			return MultiplyByTwoOperator.class;
+		}
+	}
+
+	public static class MultiplyByTwoOperator extends AbstractStreamOperatorV2<Long> implements MultipleInputStreamOperator<Long> {
+		public MultiplyByTwoOperator(StreamOperatorParameters<Long> parameters) {
+			super(parameters, 2);
+		}
+
+		@Override
+		public List<Input> getInputs() {
+			return Arrays.asList(
+					new MultiplyByTwoInput(this, 1),
+					new MultiplyByTwoInput(this, 2));
+		}
+
+		private class MultiplyByTwoInput extends AbstractInput<Long, Long> {
+			public MultiplyByTwoInput(
+					AbstractStreamOperatorV2<Long> owner,
+					int inputId) {
+				super(owner, inputId);
+			}
+
+			@Override
+			public void processElement(StreamRecord<Long> element) {
+				output.collect(element.replace(element.getValue() * 2));

Review comment:
       Should object reuse be disabled for that?

##########
File path: src/main/java/org/apache/flink/benchmark/MultipleInputBenchmark.java
##########
@@ -0,0 +1,161 @@
+/*
+ * 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.benchmark;
+
+import org.apache.flink.api.common.restartstrategy.RestartStrategies;
+import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
+import org.apache.flink.benchmark.functions.LongSource;
+import org.apache.flink.benchmark.functions.QueuingLongSource;
+import org.apache.flink.streaming.api.datastream.DataStreamSource;
+import org.apache.flink.streaming.api.datastream.MultipleConnectedStreams;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.sink.DiscardingSink;
+import org.apache.flink.streaming.api.operators.AbstractInput;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperatorFactory;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperatorV2;
+import org.apache.flink.streaming.api.operators.Input;
+import org.apache.flink.streaming.api.operators.MultipleInputStreamOperator;
+import org.apache.flink.streaming.api.operators.StreamOperator;
+import org.apache.flink.streaming.api.operators.StreamOperatorParameters;
+import org.apache.flink.streaming.api.transformations.MultipleInputTransformation;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.OperationsPerInvocation;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+import org.openjdk.jmh.runner.options.VerboseMode;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class MultipleInputBenchmark extends BenchmarkBase {
+
+	public static final int RECORDS_PER_INVOCATION = TwoInputBenchmark.RECORDS_PER_INVOCATION;
+	public static final int ONE_IDLE_RECORDS_PER_INVOCATION = TwoInputBenchmark.ONE_IDLE_RECORDS_PER_INVOCATION;
+	public static final long CHECKPOINT_INTERVAL_MS = TwoInputBenchmark.CHECKPOINT_INTERVAL_MS;
+
+	public static void main(String[] args)
+		throws RunnerException {
+		Options options = new OptionsBuilder()
+			.verbosity(VerboseMode.NORMAL)
+			.include(".*" + MultipleInputBenchmark.class.getSimpleName() + ".*")
+			.build();
+
+		new Runner(options).run();
+	}
+
+	@Benchmark
+	@OperationsPerInvocation(RECORDS_PER_INVOCATION)
+	public void multiInputMapSink(FlinkEnvironmentContext context) throws Exception {
+
+		StreamExecutionEnvironment env = context.env;
+
+		env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
+		env.setParallelism(1);
+		env.setRestartStrategy(RestartStrategies.noRestart());
+
+		// Setting buffer timeout to 1 is an attempt to improve twoInputMapSink benchmark stability.
+		// Without 1ms buffer timeout, some JVM forks are much slower then others, making results
+		// unstable and unreliable.
+		env.setBufferTimeout(1);
+
+		long numRecordsPerInput = RECORDS_PER_INVOCATION / 2;
+		DataStreamSource<Long> source1 = env.addSource(new LongSource(numRecordsPerInput));
+		DataStreamSource<Long> source2 = env.addSource(new LongSource(numRecordsPerInput));
+		connectAndDiscard(env, source1, source2);
+
+		env.execute();
+	}
+
+	@Benchmark
+	@OperationsPerInvocation(ONE_IDLE_RECORDS_PER_INVOCATION)
+	public void multiInputOneIdleMapSink(FlinkEnvironmentContext context) throws Exception {
+
+		StreamExecutionEnvironment env = context.env;
+		env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
+		env.setParallelism(1);
+
+		QueuingLongSource.reset();
+		DataStreamSource<Long> source1 = env.addSource(new QueuingLongSource(1, ONE_IDLE_RECORDS_PER_INVOCATION - 1));
+		DataStreamSource<Long> source2 = env.addSource(new QueuingLongSource(2, 1));
+		connectAndDiscard(env, source1, source2);
+
+		env.execute();
+	}
+
+	private void connectAndDiscard(
+			StreamExecutionEnvironment env,
+			DataStreamSource<Long> source1,
+			DataStreamSource<Long> source2) {
+		MultipleInputTransformation<Long> transform = new MultipleInputTransformation<>(
+				"custom operator",
+				new MultiplyByTwoOperatorFactory(),
+				BasicTypeInfo.LONG_TYPE_INFO,
+				1);
+
+		transform.addInput(source1.getTransformation());
+		transform.addInput(source2.getTransformation());
+
+		env.addOperator(transform);
+		new MultipleConnectedStreams(env)
+				.transform(transform)
+				.addSink(new DiscardingSink<>());
+	}
+
+	public static class MultiplyByTwoOperatorFactory extends AbstractStreamOperatorFactory<Long> {
+		@Override
+		public <T extends StreamOperator<Long>> T createStreamOperator(StreamOperatorParameters<Long> parameters) {
+			return (T) new MultiplyByTwoOperator(parameters);
+		}
+
+		@Override
+		public Class<? extends StreamOperator> getStreamOperatorClass(ClassLoader classLoader) {
+			return MultiplyByTwoOperator.class;
+		}
+	}
+
+	public static class MultiplyByTwoOperator extends AbstractStreamOperatorV2<Long> implements MultipleInputStreamOperator<Long> {

Review comment:
       I think this class and its factory can be private.

##########
File path: src/main/java/org/apache/flink/benchmark/MultipleInputBenchmark.java
##########
@@ -0,0 +1,161 @@
+/*
+ * 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.benchmark;
+
+import org.apache.flink.api.common.restartstrategy.RestartStrategies;
+import org.apache.flink.api.common.typeinfo.BasicTypeInfo;
+import org.apache.flink.benchmark.functions.LongSource;
+import org.apache.flink.benchmark.functions.QueuingLongSource;
+import org.apache.flink.streaming.api.datastream.DataStreamSource;
+import org.apache.flink.streaming.api.datastream.MultipleConnectedStreams;
+import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
+import org.apache.flink.streaming.api.functions.sink.DiscardingSink;
+import org.apache.flink.streaming.api.operators.AbstractInput;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperatorFactory;
+import org.apache.flink.streaming.api.operators.AbstractStreamOperatorV2;
+import org.apache.flink.streaming.api.operators.Input;
+import org.apache.flink.streaming.api.operators.MultipleInputStreamOperator;
+import org.apache.flink.streaming.api.operators.StreamOperator;
+import org.apache.flink.streaming.api.operators.StreamOperatorParameters;
+import org.apache.flink.streaming.api.transformations.MultipleInputTransformation;
+import org.apache.flink.streaming.runtime.streamrecord.StreamRecord;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.OperationsPerInvocation;
+import org.openjdk.jmh.runner.Runner;
+import org.openjdk.jmh.runner.RunnerException;
+import org.openjdk.jmh.runner.options.Options;
+import org.openjdk.jmh.runner.options.OptionsBuilder;
+import org.openjdk.jmh.runner.options.VerboseMode;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class MultipleInputBenchmark extends BenchmarkBase {
+
+	public static final int RECORDS_PER_INVOCATION = TwoInputBenchmark.RECORDS_PER_INVOCATION;
+	public static final int ONE_IDLE_RECORDS_PER_INVOCATION = TwoInputBenchmark.ONE_IDLE_RECORDS_PER_INVOCATION;
+	public static final long CHECKPOINT_INTERVAL_MS = TwoInputBenchmark.CHECKPOINT_INTERVAL_MS;
+
+	public static void main(String[] args)
+		throws RunnerException {
+		Options options = new OptionsBuilder()
+			.verbosity(VerboseMode.NORMAL)
+			.include(".*" + MultipleInputBenchmark.class.getSimpleName() + ".*")
+			.build();
+
+		new Runner(options).run();
+	}
+
+	@Benchmark
+	@OperationsPerInvocation(RECORDS_PER_INVOCATION)
+	public void multiInputMapSink(FlinkEnvironmentContext context) throws Exception {
+
+		StreamExecutionEnvironment env = context.env;
+
+		env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
+		env.setParallelism(1);
+		env.setRestartStrategy(RestartStrategies.noRestart());
+
+		// Setting buffer timeout to 1 is an attempt to improve twoInputMapSink benchmark stability.
+		// Without 1ms buffer timeout, some JVM forks are much slower then others, making results
+		// unstable and unreliable.
+		env.setBufferTimeout(1);
+
+		long numRecordsPerInput = RECORDS_PER_INVOCATION / 2;
+		DataStreamSource<Long> source1 = env.addSource(new LongSource(numRecordsPerInput));
+		DataStreamSource<Long> source2 = env.addSource(new LongSource(numRecordsPerInput));
+		connectAndDiscard(env, source1, source2);
+
+		env.execute();
+	}
+
+	@Benchmark
+	@OperationsPerInvocation(ONE_IDLE_RECORDS_PER_INVOCATION)
+	public void multiInputOneIdleMapSink(FlinkEnvironmentContext context) throws Exception {
+
+		StreamExecutionEnvironment env = context.env;
+		env.enableCheckpointing(CHECKPOINT_INTERVAL_MS);
+		env.setParallelism(1);
+
+		QueuingLongSource.reset();
+		DataStreamSource<Long> source1 = env.addSource(new QueuingLongSource(1, ONE_IDLE_RECORDS_PER_INVOCATION - 1));
+		DataStreamSource<Long> source2 = env.addSource(new QueuingLongSource(2, 1));

Review comment:
       Looking at `QueingLongSource` code, I see it can have only one active source at a time. Right?
   I guess that was reasonable for bounded inputs.
   
   But probably it makes sense to benchmark new code with multiple active sources at a time.
   WDYT?




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