[
https://issues.apache.org/jira/browse/BEAM-5211?focusedWorklogId=137658&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-137658
]
ASF GitHub Bot logged work on BEAM-5211:
----------------------------------------
Author: ASF GitHub Bot
Created on: 24/Aug/18 04:01
Start Date: 24/Aug/18 04:01
Worklog Time Spent: 10m
Work Description: tweise closed pull request #6271: [BEAM-5211] Flink
Streaming ExecutableStage operator chain blocks grpc receiver threads
URL: https://github.com/apache/beam/pull/6271
This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:
As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):
diff --git
a/runners/flink/src/main/java/org/apache/beam/runners/flink/translation/wrappers/streaming/ExecutableStageDoFnOperator.java
b/runners/flink/src/main/java/org/apache/beam/runners/flink/translation/wrappers/streaming/ExecutableStageDoFnOperator.java
index d63a3cb117e..c0e3858658a 100644
---
a/runners/flink/src/main/java/org/apache/beam/runners/flink/translation/wrappers/streaming/ExecutableStageDoFnOperator.java
+++
b/runners/flink/src/main/java/org/apache/beam/runners/flink/translation/wrappers/streaming/ExecutableStageDoFnOperator.java
@@ -23,7 +23,7 @@
import java.util.Collection;
import java.util.List;
import java.util.Map;
-import javax.annotation.concurrent.GuardedBy;
+import java.util.concurrent.LinkedBlockingQueue;
import org.apache.beam.model.pipeline.v1.RunnerApi;
import org.apache.beam.runners.core.DoFnRunner;
import org.apache.beam.runners.core.construction.graph.ExecutableStage;
@@ -39,9 +39,9 @@
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.state.TimeDomain;
import org.apache.beam.sdk.transforms.DoFn;
-import org.apache.beam.sdk.transforms.join.RawUnionValue;
import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
import org.apache.beam.sdk.util.WindowedValue;
+import org.apache.beam.sdk.values.KV;
import org.apache.beam.sdk.values.PCollectionView;
import org.apache.beam.sdk.values.TupleTag;
import org.apache.beam.sdk.values.WindowingStrategy;
@@ -73,6 +73,7 @@
private transient StateRequestHandler stateRequestHandler;
private transient BundleProgressHandler progressHandler;
private transient StageBundleFactory stageBundleFactory;
+ private transient LinkedBlockingQueue<KV<String, OutputT>> outputQueue;
public ExecutableStageDoFnOperator(
String stepName,
@@ -127,6 +128,7 @@ public void open() throws Exception {
stateRequestHandler = stageContext.getStateRequestHandler(executableStage,
getRuntimeContext());
stageBundleFactory = stageContext.getStageBundleFactory(executableStage);
progressHandler = BundleProgressHandler.unsupported();
+ outputQueue = new LinkedBlockingQueue<>();
}
// TODO: currently assumes that every element is a separate bundle,
@@ -137,12 +139,29 @@ private void
processElementWithSdkHarness(WindowedValue<InputT> element) throws
checkState(
stateRequestHandler != null, "%s not yet prepared",
StateRequestHandler.class.getName());
+ OutputReceiverFactory receiverFactory =
+ new OutputReceiverFactory() {
+ @Override
+ public FnDataReceiver<OutputT> create(String pCollectionId) {
+ return (receivedElement) -> {
+ // handover to queue, do not block the grpc thread
+ outputQueue.put(KV.of(pCollectionId, receivedElement));
+ };
+ }
+ };
+
try (RemoteBundle bundle =
- stageBundleFactory.getBundle(
- new ReceiverFactory(outputManager, outputMap),
stateRequestHandler, progressHandler)) {
+ stageBundleFactory.getBundle(receiverFactory, stateRequestHandler,
progressHandler)) {
logger.debug(String.format("Sending value: %s", element));
// TODO(BEAM-4681): Add support to Flink to support portable timers.
Iterables.getOnlyElement(bundle.getInputReceivers().values()).accept(element);
+ // TODO: it would be nice to emit results as they arrive, can thread
wait non-blocking?
+ }
+
+ // RemoteBundle close blocks until all results are received
+ KV<String, OutputT> result;
+ while ((result = outputQueue.poll()) != null) {
+ outputManager.output(outputMap.get(result.getKey()), (WindowedValue)
result.getValue());
}
}
@@ -192,32 +211,4 @@ public void finishBundle() {}
@ProcessElement
public void doNothing(ProcessContext context) {}
}
-
- /**
- * Receiver factory that wraps outgoing elements with the corresponding
union tag for a
- * multiplexed PCollection.
- */
- private static class ReceiverFactory implements OutputReceiverFactory {
-
- private final Object collectorLock = new Object();
-
- @GuardedBy("collectorLock")
- private final BufferedOutputManager<RawUnionValue> collector;
-
- private final Map<String, TupleTag<?>> outputMap;
-
- ReceiverFactory(BufferedOutputManager collector, Map<String, TupleTag<?>>
outputMap) {
- this.collector = collector;
- this.outputMap = outputMap;
- }
-
- @Override
- public <OutputT> FnDataReceiver<OutputT> create(String collectionId) {
- return (receivedElement) -> {
- synchronized (collectorLock) {
- collector.output(outputMap.get(collectionId), (WindowedValue)
receivedElement);
- }
- };
- }
- }
}
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Issue Time Tracking
-------------------
Worklog Id: (was: 137658)
Time Spent: 1h 40m (was: 1.5h)
> Flink Streaming ExecutableStage operator chain blocks grpc receiver threads
> ----------------------------------------------------------------------------
>
> Key: BEAM-5211
> URL: https://issues.apache.org/jira/browse/BEAM-5211
> Project: Beam
> Issue Type: Bug
> Components: runner-flink
> Affects Versions: 2.6.0
> Reporter: Thomas Weise
> Assignee: Thomas Weise
> Priority: Major
> Labels: portability
> Fix For: 2.7.0
>
> Attachments: jstack.log
>
> Time Spent: 1h 40m
> Remaining Estimate: 0h
>
> The operator attempts to emit results as they are received, within the grpc
> thread, while the subtask thread is waiting for bundle completion. This leads
> to blocking of grpc threads and eventually deadlock when multiple stages are
> within an operator chain. Observed with wordcount, see attached stacktrace.
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