pnowojski commented on a change in pull request #11098: [FLINK-16060][task] Implement working StreamMultipleInputProcessor URL: https://github.com/apache/flink/pull/11098#discussion_r383734977
########## File path: flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/io/StreamMultipleInputProcessor.java ########## @@ -0,0 +1,309 @@ +/* + * 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.streaming.runtime.io; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.metrics.Counter; +import org.apache.flink.runtime.io.disk.iomanager.IOManager; +import org.apache.flink.streaming.api.operators.Input; +import org.apache.flink.streaming.api.operators.MultipleInputStreamOperator; +import org.apache.flink.streaming.api.watermark.Watermark; +import org.apache.flink.streaming.runtime.metrics.WatermarkGauge; +import org.apache.flink.streaming.runtime.streamrecord.LatencyMarker; +import org.apache.flink.streaming.runtime.streamrecord.StreamRecord; +import org.apache.flink.streaming.runtime.streamstatus.StatusWatermarkValve; +import org.apache.flink.streaming.runtime.streamstatus.StreamStatus; +import org.apache.flink.streaming.runtime.streamstatus.StreamStatusMaintainer; +import org.apache.flink.streaming.runtime.tasks.OperatorChain; +import org.apache.flink.util.ExceptionUtils; + +import java.io.Closeable; +import java.io.IOException; +import java.util.List; +import java.util.concurrent.CompletableFuture; + +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * Input processor for {@link MultipleInputStreamOperator}. + */ +@Internal +public final class StreamMultipleInputProcessor implements StreamInputProcessor { + + private final MultipleInputSelectionHandler inputSelectionHandler; + + private final InputProcessor<?>[] inputProcessors; + + private final OperatorChain<?, ?> operatorChain; + + /** + * Stream status for the two inputs. We need to keep track for determining when + * to forward stream status changes downstream. + */ + private final StreamStatus[] streamStatuses; + + private final Counter numRecordsIn; + + /** Always try to read from the first input. */ + private int lastReadInputIndex = 1; + + private boolean isPrepared; + + public StreamMultipleInputProcessor( + CheckpointedInputGate[] checkpointedInputGates, + TypeSerializer<?>[] inputSerializers, + IOManager ioManager, + StreamStatusMaintainer streamStatusMaintainer, + MultipleInputStreamOperator<?> streamOperator, + MultipleInputSelectionHandler inputSelectionHandler, + WatermarkGauge[] inputWatermarkGauges, + OperatorChain<?, ?> operatorChain, + Counter numRecordsIn) { + + this.inputSelectionHandler = checkNotNull(inputSelectionHandler); + + List<Input> inputs = streamOperator.getInputs(); + int operatorsCount = inputs.size(); + + this.inputProcessors = new InputProcessor[operatorsCount]; + this.streamStatuses = new StreamStatus[operatorsCount]; + this.numRecordsIn = numRecordsIn; + + for (int i = 0; i < operatorsCount; i++) { + StreamTaskNetworkOutput dataOutput = new StreamTaskNetworkOutput<>( + inputs.get(i), + streamStatusMaintainer, + inputWatermarkGauges[i], + i); + + inputProcessors[i] = new InputProcessor( + dataOutput, + new StreamTaskNetworkInput<>( + checkpointedInputGates[i], + inputSerializers[i], + ioManager, + new StatusWatermarkValve(checkpointedInputGates[0].getNumberOfInputChannels(), dataOutput), + i)); + } + + this.operatorChain = checkNotNull(operatorChain); + } + + @Override + public CompletableFuture<?> getAvailableFuture() { + if (inputSelectionHandler.areAllInputsSelected()) { + return isAnyInputAvailable(); + } else { + throw new UnsupportedOperationException(); + } + } + + @Override + public InputStatus processInput() throws Exception { + int readingInputIndex; + if (isPrepared) { + readingInputIndex = selectNextReadingInputIndex(); + } else { + // the preparations here are not placed in the constructor because all work in it + // must be executed after all operators are opened. + readingInputIndex = selectFirstReadingInputIndex(); + } + if (readingInputIndex == -1) { + return InputStatus.NOTHING_AVAILABLE; + } + + lastReadInputIndex = readingInputIndex; + InputStatus inputStatus = inputProcessors[readingInputIndex].processInput(); + checkFinished(inputStatus, readingInputIndex); + return inputSelectionHandler.reportInputStatus(inputStatus, readingInputIndex); + } + + private int selectFirstReadingInputIndex() { + // Note: the first call to nextSelection () on the operator must be made after this operator + // is opened to ensure that any changes about the input selection in its open() + // method take effect. + inputSelectionHandler.nextSelection(); + + isPrepared = true; + + return selectNextReadingInputIndex(); + } + + private void checkFinished(InputStatus status, int inputIndex) throws Exception { + if (status == InputStatus.END_OF_INPUT) { + operatorChain.endHeadOperatorInput(getInputId(inputIndex)); + inputSelectionHandler.nextSelection(); + } + } + + @Override + public void close() throws IOException { + IOException ex = null; + for (InputProcessor<?> input : inputProcessors) { + try { + input.close(); + } catch (IOException e) { + ex = ExceptionUtils.firstOrSuppressed(e, ex); + } + } + + if (ex != null) { + throw ex; + } + } + + private int selectNextReadingInputIndex() { + if (!inputSelectionHandler.isAnyInputAvailable()) { + fullCheckAndSetAvailable(); + } + + int readingInputIndex = inputSelectionHandler.selectNextInputIndex(lastReadInputIndex); + if (readingInputIndex == -1) { + return -1; + } + + // to avoid starvation, if the input selection is ALL and availableInputsMask is not ALL, + // always try to check and set the availability of another input + if (inputSelectionHandler.shouldSetAvailableForAnotherInput()) { + fullCheckAndSetAvailable(); + } + + return readingInputIndex; + } + + private void fullCheckAndSetAvailable() { + for (int i = 0; i < inputProcessors.length; i++) { + InputProcessor<?> inputProcessor = inputProcessors[i]; + // TODO: isAvailable() can be a costly operation (checking volatile). If one of + // the input is constantly available and another is not, we will be checking this volatile + // once per every record. This might be optimized to only check once per processed NetworkBuffer + if (inputProcessor.networkInput.isApproximatelyAvailable() || inputProcessor.networkInput.isAvailable()) { + inputSelectionHandler.setAvailableInput(i); + } + } + } + + private CompletableFuture<?> isAnyInputAvailable() { + if (inputSelectionHandler.isAnyInputAvailable()) { + return AVAILABLE; + } + final CompletableFuture<?> anyInputAvailable = new CompletableFuture<>(); + for (int i = 0; i < inputProcessors.length; i++) { + if (!inputSelectionHandler.isInputFinished(i)) { Review comment: > Would probably be better to use CompletableFuture#any in any case. I was hoping to do just that, but we can not include all of the futures, so we would have to be constructing new array every time we access `CompletableFuture#anyOf(...)` - which might be quite often. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
