[FLINK-9269] Concurrency problem in HeapKeyedStateBackend when performing checkpoint async

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 1.5.0
• Fix Version/s: 1.6.0
• Component/s: Runtime / State Backends
• Assignee: Sihua Zhou
• Reporter: Sihua Zhou
• Created: 28/Apr/18 02:30
• Updated: 04/May/18 08:05
• Resolved: 04/May/18 08:05

Description

@Test
public void testConccurrencyProblem() throws Exception {

	CheckpointStreamFactory streamFactory = createStreamFactory();
	Environment env = new DummyEnvironment();
	AbstractKeyedStateBackend<Integer> backend = createKeyedBackend(IntSerializer.INSTANCE, env);

	try {
		long checkpointID = 0;
		List<Future> futureList = new ArrayList();
		for (int i = 0; i < 10; ++i) {
			ValueStateDescriptor<Integer> kvId = new ValueStateDescriptor<>("id" + i, IntSerializer.INSTANCE);
			ValueState<Integer> state = backend.getOrCreateKeyedState(VoidNamespaceSerializer.INSTANCE, kvId);
			((InternalValueState) state).setCurrentNamespace(VoidNamespace.INSTANCE);
			backend.setCurrentKey(i);
			state.update(i);

			futureList.add(runSnapshotAsync(backend.snapshot(checkpointID++, System.currentTimeMillis(), streamFactory, CheckpointOptions.forCheckpointWithDefaultLocation())));
		}

		for (Future future : futureList) {
			future.get();
		}
	} catch (Exception e) {
		fail();
	} finally {
		backend.dispose();
	}
}

protected Future<?> runSnapshotAsync(
	RunnableFuture<SnapshotResult<KeyedStateHandle>> snapshotRunnableFuture) throws Exception {

	if (!snapshotRunnableFuture.isDone()) {
		return Executors.newFixedThreadPool(5).submit(() -> {
			try {
				snapshotRunnableFuture.run();
				snapshotRunnableFuture.get();
			} catch (Exception e) {
				e.printStackTrace();
				fail();
			}
		});
	}
	return null;
}

Place the above code in `StateBackendTestBase` and run `AsyncMemoryStateBackendTest`, it will get the follows exception

java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
	at java.util.concurrent.FutureTask.get(FutureTask.java:192)
	at org.apache.flink.runtime.state.AsyncMemoryStateBackendTest.lambda$runSnapshotAsync$0(AsyncMemoryStateBackendTest.java:85)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
	at org.apache.flink.runtime.state.heap.HeapKeyedStateBackend$HeapSnapshotStrategy$1.performOperation(HeapKeyedStateBackend.java:716)
	at org.apache.flink.runtime.state.heap.HeapKeyedStateBackend$HeapSnapshotStrategy$1.performOperation(HeapKeyedStateBackend.java:662)
	at org.apache.flink.runtime.io.async.AbstractAsyncCallableWithResources.call(AbstractAsyncCallableWithResources.java:75)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at org.apache.flink.runtime.state.AsyncMemoryStateBackendTest.lambda$runSnapshotAsync$0(AsyncMemoryStateBackendTest.java:84)
	... 5 more
java.util.concurrent.ExecutionException: java.lang.NullPointerException
	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
	at java.util.concurrent.FutureTask.get(FutureTask.java:192)
	at org.apache.flink.runtime.state.AsyncMemoryStateBackendTest.lambda$runSnapshotAsync$0(AsyncMemoryStateBackendTest.java:85)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
	at org.apache.flink.runtime.state.heap.HeapKeyedStateBackend$HeapSnapshotStrategy$1.performOperation(HeapKeyedStateBackend.java:716)
	at org.apache.flink.runtime.state.heap.HeapKeyedStateBackend$HeapSnapshotStrategy$1.performOperation(HeapKeyedStateBackend.java:662)
	at org.apache.flink.runtime.io.async.AbstractAsyncCallableWithResources.call(AbstractAsyncCallableWithResources.java:75)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at org.apache.flink.runtime.state.AsyncMemoryStateBackendTest.lambda$runSnapshotAsync$0(AsyncMemoryStateBackendTest.java:84)
	... 5 more

Issue Links

• links to: GitHub Pull Request #5934