[
https://issues.apache.org/jira/browse/FLINK-13063?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Stefan Richter closed FLINK-13063.
----------------------------------
Resolution: Fixed
Release Note: This changes the default chaining behavior of the
AsyncWaitOperator. By default, we now break chains so that the
AsyncWaitOperator is never chained after another operator.
Merged in:
master: c773ce5
> AsyncWaitOperator shouldn't be releasing checkpointingLock
> ----------------------------------------------------------
>
> Key: FLINK-13063
> URL: https://issues.apache.org/jira/browse/FLINK-13063
> Project: Flink
> Issue Type: Bug
> Components: API / DataStream
> Affects Versions: 1.6.4, 1.7.2, 1.8.1, 1.9.0
> Reporter: Piotr Nowojski
> Assignee: Stefan Richter
> Priority: Blocker
> Labels: pull-request-available
> Fix For: 1.9.0
>
> Time Spent: 20m
> Remaining Estimate: 0h
>
> 1.
> For the following setup of chained operators:
> {noformat}
> SourceOperator -> FlatMap -> AsyncOperator{noformat}
> Lets assume that input buffer of {{AsyncOperator}} is full. We start
> processing a record from the {{SourceOperator}}, we pass it to the
> {{FlatMap}}, which fan it out (multiplies it 10 times). First multiplied
> record reaches {{AsyncOperator}} and is special treated (stored in
> {{AsyncWaitOperator#pendingStreamElementQueueEntry}} ) and then
> {{AsyncWaitOperator}} waits (and releases) on the checkpoint lock (in
> {{AsyncWaitOperator#addAsyncBufferEntry}} . If a checkpoint is triggered now,
> both {{SourceOperator}} and {{FlatMap}} will be checkpointed assumed that all
> of those 10 multiplied records were processed, which is not true. Only the
> first one is checkpointed by the {{AsyncWatiOperator}}. Remaining 9 are not.
> So if we ever restore state from this checkpoint, we have lost those 9
> records.
> 2.
> Similar issue (I think previously known) can happen if for example some
> upstream operator to the {{AsyncOperator}} fires a processing time timer,
> that emits some data. But in that case,
> {{AsyncWaitOperator#pendingStreamElementQueueEntry}} is being overwritten.
> 3.
> If upstream operator has the following pseudo code:
> {code:java}
> stateA = true
> output.collect(x)
> stateB = true{code}
> one would assume that stateA and stateB access/writes will be atomic from the
> perspective of the checkpoints. But again, because {{AsyncWaitOperator}}
> releases the checkpoint lock, they will not be.
> CC [~aljoscha] [~StephanEwen] [~srichter]
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
