pvary commented on code in PR #8553: URL: https://github.com/apache/iceberg/pull/8553#discussion_r1338366437
########## flink/v1.17/flink/src/main/java/org/apache/iceberg/flink/source/eventtimeextractor/EventTimeExtractorRecordEmitter.java: ########## @@ -0,0 +1,76 @@ +/* + * 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.iceberg.flink.source.eventtimeextractor; + +import org.apache.flink.api.common.eventtime.Watermark; +import org.apache.flink.api.connector.source.SourceOutput; +import org.apache.iceberg.flink.source.reader.RecordAndPosition; +import org.apache.iceberg.flink.source.reader.SerializableRecordEmitter; +import org.apache.iceberg.flink.source.split.IcebergSourceSplit; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Emitter which emits the record with event time and updates the split position. + * + * <p>The Emitter also emits watermarks at the beginning of every split, and sets the event + * timestamp based on the provided {@link IcebergEventTimeExtractor}. + */ +public final class EventTimeExtractorRecordEmitter<T> implements SerializableRecordEmitter<T> { + private static final Logger LOG = LoggerFactory.getLogger(EventTimeExtractorRecordEmitter.class); + private final IcebergEventTimeExtractor timeExtractor; + private String lastSplit = null; + private long watermark; + + public EventTimeExtractorRecordEmitter(IcebergEventTimeExtractor timeExtractor) { + this.timeExtractor = timeExtractor; + } + + @Override + public void emitRecord( + RecordAndPosition<T> element, SourceOutput<T> output, IcebergSourceSplit split) { + if (!split.splitId().equals(lastSplit)) { + long newWatermark = timeExtractor.extractWatermark(split); + if (newWatermark < watermark) { + LOG.warn( + "Watermark decreased. PreviousWM {}, currentWM {}, previousSplit {}, currentSplit {}.", + watermark, + newWatermark, + lastSplit, + split.splitId()); + } + watermark = newWatermark; + output.emitWatermark(new Watermark(watermark)); + lastSplit = split.splitId(); + } + + long eventTime = timeExtractor.extractEventTime(element.record()); + if (eventTime <= watermark) { + LOG.warn( + "Late event arrived. PreviousWM {}, split {}, eventTime {}, record {}.", + watermark, + split, + eventTime, + element.record()); + } + + output.collect(element.record(), eventTime); Review Comment: Are you suggesting, that we should use `output.collect(element.record());` instead of `output.collect(element.record(), eventTime);`? If we use `output.collect(element.record());` then it will fall back to: ``` @Override public final void collect(T record) { collect(record, TimestampAssigner.NO_TIMESTAMP); } ``` This would mean that any time we try to use the record timestamp for something, like throttling, then we will face the following exception: ``` (f70b076ad52ece48837ec5d43245d956_20ba6b65f97481d5570070de90e4e791_0_0) switched from RUNNING to FAILED with failure cause: java.lang.RuntimeException: Record has Long.MIN_VALUE timestamp (= no timestamp marker). Is the time characteristic set to 'ProcessingTime', or did you forget to call 'DataStream.assignTimestampsAndWatermarks(...)'? at org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows.assignWindows(TumblingEventTimeWindows.java:83) at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.processElement(WindowOperator.java:284) at org.apache.flink.streaming.runtime.io.RecordProcessorUtils.lambda$getRecordProcessor$0(RecordProcessorUtils.java:60) at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask$StreamTaskNetworkOutput.emitRecord(OneInputStreamTask.java:237) at org.apache.flink.streaming.runtime.io.AbstractStreamTaskNetworkInput.processElement(AbstractStreamTaskNetworkInput.java:146) at org.apache.flink.streaming.runtime.io.AbstractStreamTaskNetworkInput.emitNext(AbstractStreamTaskNetworkInput.java:110) at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:65) at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:550) at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:231) at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:839) at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:788) at org.apache.flink.runtime.taskmanager.Task.runWithSystemExitMonitoring(Task.java:952) at org.apache.flink.runtime.taskmanager.Task.restoreAndInvoke(Task.java:931) at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:745) at org.apache.flink.runtime.taskmanager.Task.run(Task.java:562) at java.base/java.lang.Thread.run(Thread.java:829) ``` So we need a way to extract the timestamp from the record to effectively use watermarks. This is one of the reasons why we used a single interface for watermark and timestamp extraction. There is not much use of one without the other. -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
