You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@druid.apache.org by GitBox <gi...@apache.org> on 2022/10/18 08:43:41 UTC
[GitHub] [druid] abhishekagarwal87 opened a new pull request, #13237: Fix race condition in HttpPostEmitter that occurs during shutdown
abhishekagarwal87 opened a new pull request, #13237:
URL: https://github.com/apache/druid/pull/13237
There is a bug (race condition) in HttpPostEmitter where the emitting thread is getting prematurely stopped while there is data to be flushed.
`HttpPostEmitter.close()` does following
```
Object lastBatch = concurrentBatch.getAndSet(null);
if (lastBatch instanceof Batch) {
flush((Batch) lastBatch);
}
```
if the emitting thread is stopped, the `flush` call will hang. In each run, emitting thread checks if `concurrentBatch.get()` returns null. If so, it will flush whatever is in the queue and shut itself down. It's possible that `flush(batch)` gets invoked after the emitting thread shuts down.
This race condition is more likely if flushMillis is set to a lower value. When that happens, the event loop in the emitting thread runs more frequently.
The race condition can easily be reproduced by adding below code to `HttpPostEmitter.close()` and running `EmitterTest.testTimeBasedEmission`
```
Object lastBatch = concurrentBatch.getAndSet(null);
Thread.sleep(60000); // new code that is to be added
if (lastBatch instanceof Batch) {
flush((Batch) lastBatch);
}
```
<!--
In each section, please describe design decisions made, including:
- Choice of algorithms
- Behavioral aspects. What configuration values are acceptable? How are corner cases and error conditions handled, such as when there are insufficient resources?
- Class organization and design (how the logic is split between classes, inheritance, composition, design patterns)
- Method organization and design (how the logic is split between methods, parameters and return types)
- Naming (class, method, API, configuration, HTTP endpoint, names of emitted metrics)
-->
<!-- It's good to describe an alternative design (or mention an alternative name) for every design (or naming) decision point and compare the alternatives with the designs that you've implemented (or the names you've chosen) to highlight the advantages of the chosen designs and names. -->
<!-- If there was a discussion of the design of the feature implemented in this PR elsewhere (e. g. a "Proposal" issue, any other issue, or a thread in the development mailing list), link to that discussion from this PR description and explain what have changed in your final design compared to your original proposal or the consensus version in the end of the discussion. If something hasn't changed since the original discussion, you can omit a detailed discussion of those aspects of the design here, perhaps apart from brief mentioning for the sake of readability of this PR description. -->
<!-- Some of the aspects mentioned above may be omitted for simple and small changes. -->
#### Release note
<!-- Give your best effort to summarize your changes in a couple of sentences aimed toward Druid users.
If your change doesn't have end user impact, you can skip this section.
-->
For tips about how to write a good release note, see [Release notes](https://github.com/apache/druid/blob/master/CONTRIBUTING.md#release-notes).
<hr>
##### Key changed/added classes in this PR
* `MyFoo`
* `OurBar`
* `TheirBaz`
<hr>
<!-- Check the items by putting "x" in the brackets for the done things. Not all of these items apply to every PR. Remove the items which are not done or not relevant to the PR. None of the items from the checklist below are strictly necessary, but it would be very helpful if you at least self-review the PR. -->
This PR has:
- [ ] been self-reviewed.
- [ ] using the [concurrency checklist](https://github.com/apache/druid/blob/master/dev/code-review/concurrency.md) (Remove this item if the PR doesn't have any relation to concurrency.)
- [ ] added documentation for new or modified features or behaviors.
- [ ] a release note entry in the PR description.
- [ ] added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
- [ ] added or updated version, license, or notice information in [licenses.yaml](https://github.com/apache/druid/blob/master/dev/license.md)
- [ ] added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
- [ ] added unit tests or modified existing tests to cover new code paths, ensuring the threshold for [code coverage](https://github.com/apache/druid/blob/master/dev/code-review/code-coverage.md) is met.
- [ ] added integration tests.
- [ ] been tested in a test Druid cluster.
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org
For additional commands, e-mail: commits-help@druid.apache.org
[GitHub] [druid] abhishekagarwal87 merged pull request #13237: Fix race condition in HttpPostEmitter that occurs during shutdown
Posted by GitBox <gi...@apache.org>.
abhishekagarwal87 merged PR #13237:
URL: https://github.com/apache/druid/pull/13237
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@druid.apache.org
For additional commands, e-mail: commits-help@druid.apache.org