pnowojski commented on code in PR #20158: URL: https://github.com/apache/flink/pull/20158#discussion_r914778495
########## flink-tests/src/test/java/org/apache/flink/test/streaming/api/datastream/FinishedSourcesWatermarkITCase.java: ########## @@ -0,0 +1,131 @@ +/* + * 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.test.streaming.api.datastream; + +import org.apache.flink.api.common.state.CheckpointListener; +import org.apache.flink.configuration.Configuration; +import org.apache.flink.streaming.api.datastream.DataStream; +import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment; +import org.apache.flink.streaming.api.functions.co.CoProcessFunction; +import org.apache.flink.streaming.api.functions.sink.SinkFunction; +import org.apache.flink.streaming.api.functions.source.RichSourceFunction; +import org.apache.flink.streaming.api.watermark.Watermark; +import org.apache.flink.util.Collector; +import org.apache.flink.util.TestLogger; + +import org.joda.time.DateTime; +import org.junit.Test; + +import java.util.concurrent.atomic.AtomicLong; + +/** Test that ensures watermarks are correctly propagating with finished sources. */ +public class FinishedSourcesWatermarkITCase extends TestLogger { + + private static final AtomicLong ACTUAL_DOWNSTREAM_WATERMARK = new AtomicLong(0); + + @Test + public void testTwoConsecutiveFinishedTasksShouldPropagateMaxWatermark() throws Exception { + Configuration conf = new Configuration(); + StreamExecutionEnvironment env = StreamExecutionEnvironment.createLocalEnvironment(1); + + // disable chaining to make sure we will have two consecutive checkpoints with Task == + // FINISHED + env.disableOperatorChaining(); + env.enableCheckpointing(100); + + // create our sources - one that will want to run forever, and another that finishes + // immediately + DataStream<String> runningStreamIn = + env.addSource(new LongRunningSource(), "Long Running Source"); + DataStream<String> emptyStream = + env.addSource(new ShortLivedEmptySource(), "Short Lived Source"); + + // pass the empty stream through a simple map() function + DataStream<String> mappedEmptyStream = emptyStream.map(v -> v).name("Empty Stream Map"); + + // join the two streams together to see what watermark is reached during startup and after a + // recovery + runningStreamIn + .connect(mappedEmptyStream) + .process(new MyCoProcessFunction()) + .name("Join") + .addSink( + new SinkFunction<String>() { + @Override + public void writeWatermark( + org.apache.flink.api.common.eventtime.Watermark watermark) { + ACTUAL_DOWNSTREAM_WATERMARK.set(watermark.getTimestamp()); + } + }); + + env.execute(); + } + + private static class LongRunningSource extends RichSourceFunction<String> + implements CheckpointListener { + private volatile boolean isRunning = true; + private transient long lastSuccessfulCheckpointId; + + @Override + public void run(SourceContext<String> sourceContext) throws Exception { + long expectedWatermark = Watermark.MAX_WATERMARK.getTimestamp(); + long watermark = DateTime.now().getMillis(); + sourceContext.emitWatermark(new Watermark(watermark)); + + while (isRunning && expectedWatermark > ACTUAL_DOWNSTREAM_WATERMARK.get()) { + synchronized (sourceContext.getCheckpointLock()) { + watermark = DateTime.now().getMillis(); + sourceContext.emitWatermark(new Watermark(watermark)); + if (lastSuccessfulCheckpointId == 5) { + throw new RuntimeException("Force recovery"); + } + if (lastSuccessfulCheckpointId > 10 && expectedWatermark > watermark) { Review Comment: Re this and above. This is kind of the point here. We are waiting until 10th checkpoint. On the 10th checkpoint, we are recoding what was the last emitted watermark, and remembering it to be the `expectedWatermark`. Then we are still running unknown number of iterations, until the downstream sink finally receives this `expectedWatermark`. Hence we can not get rid of `expectedWatermark > ACTUAL_DOWNSTREAM_WATERMARK.get()`. I will try to rephrase the code a bit, to make it more explicit/clear. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
