rkhachatryan commented on a change in pull request #11486: [FLINK-16712][task]
Refactor StreamTask to construct final fields
URL: https://github.com/apache/flink/pull/11486#discussion_r396592181
##########
File path:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/tasks/StreamTask.java
##########
@@ -260,17 +258,28 @@ protected StreamTask(
@Nullable TimerService timerService,
Thread.UncaughtExceptionHandler
uncaughtExceptionHandler,
StreamTaskActionExecutor actionExecutor,
- TaskMailbox mailbox) {
+ TaskMailbox mailbox) throws Exception {
super(environment);
- this.timerService = timerService;
- this.uncaughtExceptionHandler =
Preconditions.checkNotNull(uncaughtExceptionHandler);
this.configuration = new StreamConfig(getTaskConfiguration());
this.recordWriter = createRecordWriterDelegate(configuration,
environment);
this.actionExecutor =
Preconditions.checkNotNull(actionExecutor);
this.mailboxProcessor = new
MailboxProcessor(this::processInput, mailbox, actionExecutor);
this.asyncExceptionHandler = new
StreamTaskAsyncExceptionHandler(environment);
+ this.asyncOperationsThreadPool = Executors.newCachedThreadPool(
+ new ExecutorThreadFactory("AsyncOperations",
uncaughtExceptionHandler));
+
+ this.stateBackend = createStateBackend();
+ this.checkpointStorage =
stateBackend.createCheckpointStorage(getEnvironment().getJobID());
+
+ // if the clock is not already set, then assign a default
TimeServiceProvider
+ if (timerService == null) {
+ ThreadFactory timerThreadFactory = new
DispatcherThreadFactory(TRIGGER_THREAD_GROUP, "Time Trigger for " + getName());
+ this.timerService = new
SystemProcessingTimeService(this::handleTimerException, timerThreadFactory);
+ } else {
Review comment:
I'm a bit concerned about concurrency here: we publish a reference to this
object before it's being fully constructed.
So the other thread can read null as `asyncExceptionHandler` value.
But now this field is final, so the preceding write to it should be already
visible.
If this is correct, I think we need to put a warning here and near `final`
modifier that changing them can cause concurrency problems.
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