[
https://issues.apache.org/jira/browse/FLINK-10255?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16612347#comment-16612347
]
ASF GitHub Bot commented on FLINK-10255:
----------------------------------------
GJL commented on a change in pull request #6678: [FLINK-10255] Only react to
onAddedJobGraph signal when being leader
URL: https://github.com/apache/flink/pull/6678#discussion_r217082586
##########
File path:
flink-runtime/src/main/java/org/apache/flink/runtime/dispatcher/Dispatcher.java
##########
@@ -879,24 +917,66 @@ public void handleError(final Exception exception) {
@Override
public void onAddedJobGraph(final JobID jobId) {
- final CompletableFuture<SubmittedJobGraph> recoveredJob =
getRpcService().execute(
- () -> submittedJobGraphStore.recoverJobGraph(jobId));
-
- final CompletableFuture<Acknowledge> submissionFuture =
recoveredJob.thenComposeAsync(
- (SubmittedJobGraph submittedJobGraph) ->
submitJob(submittedJobGraph.getJobGraph(), RpcUtils.INF_TIMEOUT),
- getMainThreadExecutor());
-
- submissionFuture.whenComplete(
- (Acknowledge acknowledge, Throwable throwable) -> {
- if (throwable != null) {
- onFatalError(
- new DispatcherException(
- String.format("Could
not start the added job %s", jobId),
-
ExceptionUtils.stripCompletionException(throwable)));
+ runAsync(
+ () -> {
+ if (!jobManagerRunners.containsKey(jobId)) {
+ final CompletableFuture<JobGraph>
recoveredJob = recoveryOperation.thenApplyAsync(
+ ignored -> {
+ try {
+ return
recoverJob(jobId);
+ } catch (Exception e) {
+
ExceptionUtils.rethrow(e);
+ }
+ return null;
+ },
+ getRpcService().getExecutor());
+
+ final DispatcherId dispatcherId =
getFencingToken();
+ final CompletableFuture<Void>
submissionFuture = recoveredJob.thenComposeAsync(
+
(FunctionWithThrowable<JobGraph, CompletableFuture<Void>, Exception>) (JobGraph
jobGraph) -> tryRunRecoveredJobGraph(jobGraph, dispatcherId)
+ .thenAcceptAsync(
+
(ConsumerWithException<Boolean, Exception>) (Boolean isRecoveredJobRunning) -> {
Review comment:
Imo we are doing this wrong. The API would be much more readible with static
factory methods:
```
/**
* {@link Consumer} that can throw checked exceptions.
*/
@FunctionalInterface
public interface CheckedConsumer<T> {
void checkedAccept(T t) throws Exception;
static <T> Consumer<T> unchecked(CheckedConsumer<T> checkedConsumer) {
return (t) -> {
try {
checkedConsumer.checkedAccept(t);
} catch (Exception e) {
ExceptionUtils.rethrow(e);
}
};
}
}
```
This allows for:
```
CheckedConsumer.unchecked(isRecoveredJobRunning -> {
...
});
```
No casts are required. Also when interacting with the Java API, it does not
matter what exact type of exception can be thrown – what matters is that the
checked exception becomes a unchecked. We do not need to generify the exception
type in `ConsumerWithException`.
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> Standby Dispatcher locks submitted JobGraphs
> --------------------------------------------
>
> Key: FLINK-10255
> URL: https://issues.apache.org/jira/browse/FLINK-10255
> Project: Flink
> Issue Type: Bug
> Components: Distributed Coordination
> Affects Versions: 1.5.3, 1.6.0, 1.7.0
> Reporter: Till Rohrmann
> Assignee: Till Rohrmann
> Priority: Blocker
> Labels: pull-request-available
> Fix For: 1.6.1, 1.7.0, 1.5.4
>
>
> Currently, standby {{Dispatchers}} lock submitted {{JobGraphs}} which are
> added to the {{SubmittedJobGraphStore}} if HA mode is enabled. Locking the
> {{JobGraphs}} can prevent their cleanup leaving the system in an inconsistent
> state.
> The problem is that we recover in the
> {{SubmittedJobGraphListener#onAddedJobGraph}} callback which is also called
> if don't have the leadership the newly added {{JobGraph}}. Recovering the
> {{JobGraph}} currently locks the {{JobGraph}}. In case that the
> {{Dispatcher}} is not the leader, then we won't start that job after its
> recovery. However, we also don't release the {{JobGraph}} leaving it locked.
> There are two possible solutions to the problem. Either we check whether we
> are the leader before recovering jobs or we say that recovering jobs does not
> lock them. Only if we can submit the recovered job we lock them. The latter
> approach has the advantage that it follows a quite similar code path as an
> initial job submission. Moreover, jobs are currently also recovered at other
> places. In all these places we currently would need to release the
> {{JobGraphs}} if we cannot submit the recovered {{JobGraph}} (e.g.
> {{Dispatcher#grantLeadership}}).
> An extension of the first solution could be to stop the
> {{SubmittedJobGraphStore}} while the {{Dispatcher}} is not the leader. Then
> we would have to make sure that no concurrent callback from the
> {{SubmittedJobGraphStore#SubmittedJobGraphListener}} can be executed after
> revoking leadership from the {{Dispatcher}}.
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